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1
Le, Pennec Fabien. "Développement de microcapteurs pour la mesure de dioxyde de carbone (CO2) : application au suivi de la qualité de l’air." Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0148.
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A la différence de la pollution de l’air extérieur, celle de l’air intérieur est restée relativement peu étudiée jusqu’au début des années 2000. Pourtant, nous passons en moyenne 85 % de notre temps dans des environnements clos (domicile, bureaux, transports…) dans lesquels nous sommes exposés à de nombreux polluants. De nombreuses études ont montré que la mesure de la concentration du dioxyde de carbone, permet d’évaluer le confinement de l’air intérieur. Pour mesurer les polluants, nous pouvons distinguer les analyseurs et les microcapteurs, avec chacun ses avantages et ses inconvénients. Dans le cas de la qualité de l’air intérieur, les microcapteurs de type résistif paraissent comme la solution la plus appropriée, de par leur faible coût, leur haute sensibilité, leur miniaturisation possible et leur faible consommation. Le phénomène de détection s’établit sur la variation de la résistance électrique de l’élément sensible en réponse à un taux d’adsorption du gaz. Mes travaux de recherche se sont concentrés sur l’étude de la couche sensible. Nous avons utilisé la méthode de dépôt par screen printing, technique simple, rapide et peu coûteuse. La structure cristalline et la morphologie ont pu être déterminées ainsi que l’identification des substances chimiques présentes dans nos matériaux suivant des techniques de caractérisations physico-chimiques. Nos résultats ont montré que les capteurs réalisés à base de La2O2CO3 et de BaTiO3, respectivement, présentent de bonnes performances, avec une forte sensibilité au CO2, et un bon taux de répétabilitéUnlike outdoor air pollution, indoor air pollution remained relatively understudied until the early 2000s. However, we spend on average 85% of our time in closed environments (home, offices, transport, etc. in which we are exposed to many pollutants. Numerous studies have shown that measuring the concentration of carbon dioxide makes it possible to assess the confinement of indoor air. To measure pollutants, we can distinguish between analyzers and microsensors, each with its advantages and disadvantages. In the case of indoor air quality, resistive type microsensors appear to be the most appropriate solution, due to their low cost, high sensitivity, possible miniaturization and low power consumption. The detection phenomenon is based on the variation of the electrical resistance of the sensitive element in response to a gas adsorption rate. My research work has focused on the study of the sensitive layer. We used the screen-printing deposit method, a simple, fast and inexpensive technique. The crystalline structure and the morphology could be determined as well as the identification of the chemical substances present in our materials according to physico-chemical characterization techniques. Our results showed that the sensors made from La2O2CO3 and BaTiO3, respectively, present good performances, with a high sensitivity to CO2, and a good repeatability rate
2
Zhang, Rong. "Zinc Oxide Thin Films for Dye-Sensitized Solar Cell Applications." Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1186016777.
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Nateq, Mohammad Hosein. "Enhancing the Photo-electrode Features to Improve the Solar Conversion Efficiency in the Dye-Sensitized Solar Cell." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/243450.
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Mesoporous semiconductors such as TiO2 nanoparticles, as well as transparent conducting oxides (TCOs) such as indium tin oxide films are typically employed for setting up the photo-electrode module in variety of photoelectrochemical cells including Dye-Sensitized Solar Cells (DSSCs). In order to exhibit a high performance efficiency, the photo-electrodes in such applications are required to be able to harvest the light and transport the generated electrons effectively. Accordingly mesoporous layers with high values of surface area and well-established pore structure along with highly transparent and conductive TCOs are deposited on suitable substrates through the physical or chemical vapor deposition methods. The processing facilities and materials required to fabricate such high-quality devices with high values of efficiency are complicated and expensive, whereas devices of lower quality do not fulfill the demands. This issue is of particular importance regarding the energy production and developing the solar cell technologies, as it is considered by the concept of “cost per watt”. Thus, a great deal of effort is being carried out globally to enhance the efficiency of affordably-produced solar cells such as low-cost DSSCs. Utilizing the wet chemical techniques such as sol-gel method which provide a considerably more affordable route to synthesize nanoparticles and deposit thin films without the need of applying high temperature or vacuum condition is a widely-used approach to decrease the processing expenses. However, to achieve an acceptable cost-per-watt ratio requires enhancing the obtained efficiency value as well, and therefore, modifying the processing procedures to improve the required features of the products are highly encouraged. This thesis focuses on two individual activities: synthesis of TiO2 nanoparticles, and also thin film deposition of a promising TCO called aluminum-doped zinc oxide (AZO); both obtained through the sol-gel route that is modified to contribute to nanostructures with suitable features for application in photoelectrochemical devices such as DSSC. In the first part, mesoporous anatase nanoparticles were synthesized through the surfactant-mediated sol–gel route. Through changing the refluxing time and water-to-surfactant molar ratio, as-prepared nanocrystals of high density and large and narrowly-distributed pore sizes were obtained, displaying surface area values up to 240 m2·g-1, much higher than the reported values for commercial TiO2-based catalysts. In the second part, sol–gel dip–coating of ZnO thin films doped with 2 at.% of aluminium ions was carried out. By altering the hydrolysis reaction and changing the thermal treatment procedure, thin films of highly c-axis preferred orientation were obtained with optical transmittance of around 80% and resistivity values down to 6 – 15 mΩ·cm, corresponding to sheet resistance of around Rsh ~ 500 Ω/sq. The obtained conductivity values, even though one order magnitude lower than those reported for the AZO thin film prepared via expensive techniques, are in the suitable range to improve the cost per watt ratio in applications such as inkjet printing of low-cost printed electronics and more affordable DSSC devices.
4
Nateq, Mohammad Hosein. "Enhancing the Photo-electrode Features to Improve the Solar Conversion Efficiency in the Dye-Sensitized Solar Cell." Doctoral thesis, Università degli studi di Trento, 2019. http://hdl.handle.net/11572/243450.
Full textAbstract:
Mesoporous semiconductors such as TiO2 nanoparticles, as well as transparent conducting oxides (TCOs) such as indium tin oxide films are typically employed for setting up the photo-electrode module in variety of photoelectrochemical cells including Dye-Sensitized Solar Cells (DSSCs). In order to exhibit a high performance efficiency, the photo-electrodes in such applications are required to be able to harvest the light and transport the generated electrons effectively. Accordingly mesoporous layers with high values of surface area and well-established pore structure along with highly transparent and conductive TCOs are deposited on suitable substrates through the physical or chemical vapor deposition methods. The processing facilities and materials required to fabricate such high-quality devices with high values of efficiency are complicated and expensive, whereas devices of lower quality do not fulfill the demands. This issue is of particular importance regarding the energy production and developing the solar cell technologies, as it is considered by the concept of “cost per watt”. Thus, a great deal of effort is being carried out globally to enhance the efficiency of affordably-produced solar cells such as low-cost DSSCs. Utilizing the wet chemical techniques such as sol-gel method which provide a considerably more affordable route to synthesize nanoparticles and deposit thin films without the need of applying high temperature or vacuum condition is a widely-used approach to decrease the processing expenses. However, to achieve an acceptable cost-per-watt ratio requires enhancing the obtained efficiency value as well, and therefore, modifying the processing procedures to improve the required features of the products are highly encouraged. This thesis focuses on two individual activities: synthesis of TiO2 nanoparticles, and also thin film deposition of a promising TCO called aluminum-doped zinc oxide (AZO); both obtained through the sol-gel route that is modified to contribute to nanostructures with suitable features for application in photoelectrochemical devices such as DSSC. In the first part, mesoporous anatase nanoparticles were synthesized through the surfactant-mediated sol–gel route. Through changing the refluxing time and water-to-surfactant molar ratio, as-prepared nanocrystals of high density and large and narrowly-distributed pore sizes were obtained, displaying surface area values up to 240 m2·g-1, much higher than the reported values for commercial TiO2-based catalysts. In the second part, sol–gel dip–coating of ZnO thin films doped with 2 at.% of aluminium ions was carried out. By altering the hydrolysis reaction and changing the thermal treatment procedure, thin films of highly c-axis preferred orientation were obtained with optical transmittance of around 80% and resistivity values down to 6 – 15 mΩ·cm, corresponding to sheet resistance of around Rsh ~ 500 Ω/sq. The obtained conductivity values, even though one order magnitude lower than those reported for the AZO thin film prepared via expensive techniques, are in the suitable range to improve the cost per watt ratio in applications such as inkjet printing of low-cost printed electronics and more affordable DSSC devices.
5
Du, Juan [Verfasser]. "Electrochemical deposition of dye-modified ZnO hybrid thin films and their application to flexible dye-sensitized solar cells / Juan Du." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2013. http://d-nb.info/1032724811/34.
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Wu, Kuei-Sian, and 吳奎憲. "The influence of thin film deposition technologies on dye-sensitized solar cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/00349664421013019959.
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碩士樹德科技大學
電腦與通訊系碩士班
103
In this study, the working electrode of dye-sensitized solar cells (DSSCs) based on all titanium substrates were investigated. Experimentally, electrophoretic deposition and anodic oxidation method will be employed to fabricate the working electrodes of flexible DSSCs. The goals of the project aim to build a high performance electrode with low series resistance, highly conducting charge-transfer, high reduction catalytic activity and good stability. Experimental results show that the optimized anodization condition for preparing titanium dioxide (TiO2) on the titanium mesh is 0.035 M of ammonium fluoride, 400 mA of applied current.
7
Yen-YuChu and 朱彥宇. "Electrophoretic Deposition of TiO2 Films for Dye-Sensitized Solar Cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/67739983625349089063.
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碩士國立成功大學
化學工程學系碩博士班
98
The charge transfer rate in the nanocrystalline TiO2 electrode govern the performance of a dye-sensitized solar cell(DSSC). In this study, TiO2 colloids derived from a titanate-directed route and used to prepare electrode by two methods: Paste-coating and Electrophoretic Deposition. Nitrogen absorption-desorption and SEM was used to analysis the pore and electrode morphology. In order to compare the difference of charge transfer, IMPS, IMVS, and EIS were used. By the analysis of nitrogen absorption-desorption and SEM, electrophoretic solution has higher surface area, and the electrode morphology was dense packing. Cell performance of electrophoretic electrode was better than paste-coating because of its high current density. IMPS showed a higher electron transfer rate for electrophoretic electrode, but the electron lifetime is shorter by the IMVS analyzing. In EIS testing, the charge collection efficiency and diffusion length were 91% and 43?m, respectively. The dense packing caused the much more dye to absorb, decreased the path for electron transfer, so electrophoretic electrode has higher charge collection efficiency, current density, and lower open-circuit voltage.
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Chen, Chang-Yi, and 陳昌詣. "Application and Preparation TiO2 Film on Flexible Dye-Sensitized Solar Cells by Electrophoretic Deposition." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/81400605372982130421.
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碩士明志科技大學
化學工程研究所
98
This study mainly investigated the preparation of the working electrode, the modification of the corresponding electrode and the preparation of a dye-sensitized solar cell (DSSC) on a flexible polyethylene terephthalate (PET) substrate. We hoped that this study can effectively improve the efficiency of a flexible DSSC. During processing a DSSC, we used several film formation methods including electrophoretic deposition, mechanical compression and the chemical binding to improve the DSSC. Then we measured the characteristics of the obtained cell via cyclic voltammetry, DC polarization and AC impedance spectroscopy. The experiment results showed that using the multiple electrophoretic depositions to prepare a TiO2 film could cover the cracks formed by the evaporation of the organic solvent and thus provide better film quality. The optimal thickness of a TiO2 film was 15 μm, which can lead to a maximum short–circuit current of a DSSC when the open circuit potential maintained the same value. When magnesium nitrate was added to the solution used in electrophoretic deposition, the obtained TiO2 film was compact and stable on a PET substrate. Furthermore, this study used self-assembled monolayer (SAM) to modify the counter electrode. Then the characteristics of the electrode were changed by SAM. The result showed that the counter electrode coated SAM was not as expected because SAM prevented the redox electrolyte to penetrate, leading to low currents during an electrochemical reaction.
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Yong-JinLiou and 劉永進. "Electrophoretic Deposition of Rigid and Flexible TiO2 Films for Dye-Sensitized Solar Cells." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/86805948241123466438.
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Liang-CheChen and 陳良哲. "Electrophoretic Deposition of TiO2 Films for Flexible Dye-Sensitized Solar Cells with Backside Illumination." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/20187119800835922863.
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碩士國立成功大學
化學工程學系碩博士班
100
We use electrophoretic deposition (EPD) method to deposite TiO2 nanoparticles on the Ti foil, consisting of repetitive short-term depositions with intermediate drying to prepare nanocrystalline TiO2 films for dye-sensitized solar cells (DSSCs). After calcination, the EPD TiO2 films exhibited a more compact TiO2 network. The effect of five factors, i.e., (i) the thickness of platinum film sputtered on the counter electrode, (ii) sintering temperature of TiO2-coated Ti foil, (iii) the concentration of iodine in the electrolyte, (iv) thickness of TiO2 film, (v) the effect of the scattering layer deposited between the Ti foil and the transparent layer are reported for the photovoltaic performance of a back-illuminated flexible dye-sensitized solar cell with Ti foil substrate for the TiO2 layer. Optimization of these five factors yields a solar cell conversion efficiency 7%. X-ray diffraction (XRD), scanning electron micrographs (SEM), UV-Visible spectrophotometer, intensity-modulated photocurrent spectroscopy (IMPS), intensity-modulated photovoltage spectroscopy (IMVS) and electrochemical impedance spectroscopy (EIS) are used to substantiate the explanation.
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Zhang, Zhi-Jia, and 張志嘉. "Electrophoretic Deposition of Graphene－Based Thin Films and its Application in Dye-Sensitized Solar Cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/46276798348586535989.
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碩士大葉大學
工業工程與管理學系
103
This study can be divided into two parts. In the first part, In spin coating method graphene suspension was uniformly dispersed onto Corning 1737 glass, Preparation of the conductive film: Then by electrophoresis deposition method, compared the graphene deposited on ITO glass substrate. The catalytic through modified Hummers method, So more efficiently dispersed graphene in solution, The four-point probe in electrophoretic deposition of graphene way better than the effect of the spin coating method;Then using Hall Effect analyzed, The results show that the deposition parameters 10v60s best carrier concentration of 4.34 (× 1017cm-3). The second part is the electrophoretic deposition of graphene deposited on ITO substrate. As the dye-sensitized solar cell electrode, then replaces the platinum electrode, by controlling the voltage and time of the preparation to corresponding electrode. The working electrode layer is three TiO2, Its photoelectric conversion efficiency measured DSSC, The photoelectric conversion efficiency of DSSC measurements AM1.5 simulated solar light irradiated to the element results: 10v-60s deposition of electrodes is better, η% with increasing voltage and time, its efficiency will be a slight increase.
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Yang, Gung-Chuen, and 楊公錞. "Applications of nanocrystalline TiO2 films prepared by electrophoretic deposition on flexible dye-sensitized solar cells." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/m5h6vh.
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碩士國立虎尾科技大學
光電與材料科技研究所
96
The dye-sensitization solar cell is a kind of low-cost solar cell with high efficiency developed by Swiss M. Gratzel laboratory in 1991. The electrode is made by utilizing nano-grade crystallization of TiO2 porous thin film. After processing by Ru-complex of day-sensitization and using the iodine/ the iodine ion solution as the electrolyte to the conductive ITO glass on the metal of platinum of electrode plate, the dye-sensitization solar cell is made. Basically, TiO2 electrode plays a most important role on an efficient dye-sensitization solar cell. It must offer the route of electric and surface area that dye absorption, and also need porous structure to help diffusion of electrolyte. It will improve the ability of absorbing the sunlight of photoelectric positive pole that the photosensitive dye molecule adhere the TiO2 surface of nano-grade semiconductor. As the small area, heavy roughness, big surface area composed by nano-grade TiO2 porous structure, it can offer sufficient area of absorbing dye molecule even only one stratum dye on the surface. It shows high absorption efficiency in UV light regions. In this study, we choose the electrophoresis depositing method to make the thin film electrode of TiO2 is due to electrophoresis depositing method has the advantages of simple and cheap production equipment, high-speed depositing, low-temperature production suitable for material plating membrane. Utilizing electrophoresis to manufacture TiO2 thin film can improve TiO2 nano thin film structure and producing the usage that TiO2 nanotubes applied on electrode material. We also use various dye to compare the differences of efficiency and produce colloidal electrolytic liquid to replace electrolytic liquid to improve the assembling of solar cell. These methods are applied to produce high-efficiency dye-sensitization solar cells. TiO2 nanoparticles were calcined 450 oC in high-temperature stove for 30 minutes and put the calcined TiO2 nanoparticles in 100ml isopropyl alcohol, the concentration of particle was about 0.35g/l. Then add nitric acid magnesium which the concentration was 1x10-4 M as electrolyte of producing TiO2 suspension, then TiO2 suspension liquid was finished. And the working electrode regarded Pt side as the positive pole, the plastic sill as the negative pole, the regular interval between two poles was 15mm. Put two electrodes into TiO2 suspension and utilized the galvanic power supplying device to bestow the regular applied voltage. The voltage value was 40V, electric current value was 0.005 mA. As depositing for 3 minutes, the TiO2 thin film was finished. In the electrophoresis process, we stirred the suspension continuously with the magnetism at the same time in order to prevent the particle from condensing and subsiding. TiO2 membrane was compressed by the automatic compressor for 2 minutes. The pressure was 200 bar. In order to produce TiO2 nanotubes, we put the calcined TiO2 nanoparticles and NaOH solid with the weight ratio 1/ 80 in deionized water to prepare 200 milliliters of solution. Then put this solution in the serum bottle, and made it maintain 110 oC by utilizing oil bath heat for 60 hours. After the reaction was finished, we proceeded the cooling still first, and poured the cooled solution to the beaker for the washing procedure, and then put 1M HCl aqueous solution constantly in the acid washing process until the aqueous solution presented acid (pH =1) and the solid powder precipitated at the bottom of the cup. Then put this cup of solution in air for 24 hours and washed the solid powder with iron water constantly until the solution pH value was close to 7. While filtering the solid powder close to neutral, then baked it under 80 oC and collected by grinding. Thus we could get TiO2 nanotubes with high production rate and higher consistence. Finally, we fetched appropriate amount TiO2 nanotubes to mix TiO2 suspension, and utilized TiO2 nanotubes thin film that electrophoresis method depositing needed. We soaked the finished TiO2 nano thin film on EY and N3 dye which the concentration were 1x10-3 M to proceed the absorption. Then utilized the steam and plate method to prepare platinum side electrodes. Mixed the acetonitrile which contains KI of 0.5M and I2 of 0.05M to produce the liquid electrolyte. The colloidal electrolyte was regarded as the liquid electrolyte and it’s 7g EC mixed PC of 3g and join KI of 1.1g and PEG of 3g, then heated by 70 oC for 30 minutes by adding 6g acrylamide monomer then blended the 0.06g ammonium persulfate and PEG of 1g to be colloidal electrolyte. Mixed the liquid electrolytic colloidal solution finally and the colloidal electrolytic was finished. For assembling the TiO2 electrode, we soaked and absorbed the dye and the sandwich-structure solar cell component formed by Pt electrode in the 3mm-thickness fillister of plastic slice between two poles. And the equipment of the solar cell component of day sensitization was finished. We used the "Newport Oriel Instruments" simulated sunlight as source that streams in through our build-up sensitization solar cell component to measure its voltages, currents and efficiency by utilizing PL = 100mW/cm2 (AM 1.5) According to XRD analysis, the membrane deposited by electrophoresis after calcined commercially TiO2 nanoparticle by 450 oC is the anatase phase as we required. From the results of SEM, we can observe that the membrane surface gets compact thru compress process, and that it’s helpful for electron transmit and enhancing the contact area with dye. The dye is selected from N3 dye with Ru-complex, it can help enhance light exciting wave band of TiO2 to visible area. And observing from absorbing spectrogram, TiO2 after absorbing the dye will have stronger ability of light absorption. TiO2 nanotube has the character of bigger surface area and bigger pore diameter is useful for diffusion of the electrolytic liquid and the absorption of dyes molecule. It is provided an improvement way to enhance the efficiency of the dye-sensitization solar cell.
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Li-ChiehChen and 陳立捷. "Electrophoretic Deposition of TiO2 Film Photoanodes for Use in All-plastic Flexible Dye-Sensitized Solar Cells Having Gel Electrolyte." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/91559184619674561186.
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碩士國立成功大學
材料科學及工程學系碩博士班
100
All-plastic flexible dye-sensitized solar cell (FDSC) is becoming more and more important due to its light-weight and suitable for roll-to-roll process. However, fabrication of the TiO2 photoanode on the plastic substrate must be done at tolerate a temperature lower than 150°C. The low temperature also posts a thread of binder contamination. In this study, we report a binder-free electrophoretic deposition (EPD) combined with mechanical compression for the fabrication TiO2 photoanodes on plastic substrates for use in all plastic substrate FDSCs having a gel electrolyte. The photoanodes were composed of 20-nm P25 TiO2 powders with and without the addition of 160-nm ST41 TiO2 powders. The EPD was performed under various conditions to obtained photoanodes having different thicknesses and porosities. We show that the EPD process allows the control of not only the thickness but also the porosities and dye loading of the photoanode. Depending on these characteristics, photoanodes exhibiting different light absorbance, dye loadings, and electron injection efficiencies were obtained. These characteristics in turn dominate the electron diffusion time and electron lifetime. As a result, we obtained the highest electron diffusion time and electron life time was 2.58 ms and 32.05 ms, respectively. The addition of 160-nm TiO2 powders leads to enhanced light absorptance because they serve as light scattering centers, thus reducing the electron diffusion time. In other words, the electron diffusion rate of the addition of 160nm showed more than two-fold enrichment. Compared to the 20-nm TiO2 only cells, the addition of 160-nm TiO2 powders enhances the conversion efficiency by as much as 22%.
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Lin, Chun-Min, and 林峻民. "Electrochemical deposition of Zinc Oxide Thin Films and Their Application to Flexible Dye-Sensitized Solar Cells." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/np9j8u.
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碩士國立臺北科技大學
有機高分子研究所
100
In this study ZnO nanoporous films were prepared by using the electrochemical deposition method with oxygen bubbling and fabricated into DSSC photoanodes. The factors investigated included electrodeposition with oxygen bubbling and low-temperature calcination time, organic and inorganic complexes dyes and thickness of the relationship between, flexible titanium substrate surface treatment on the back-illuminated cell efficiency. the choice of three different surface treatments, respectively, hydrogen treatment, polished and high-temperature sintering process, the titanium substrate, compared with untreated control group. The calcination time at 150℃ was varied from 1 to 24 hours. The results show that the as-deposited precursor nanosheets were roughly vertically aligned with the glass substrate and formed a connecting network with space between them. Calcination at 150℃not only converted the precursor into ZnO, but also generated numerous through pores on the nanosheets. Such a structure should be favorable for photoanode construction, because the porous nanosheets provide a relatively large surface area for dye adsorption, and the vertically standing nanosheets give a direct conduction pathway for electron transport. In order to determine the optimal calcination time at 150℃, the calcination time was varied from 1 to 24 h, while the thickness of the ZnO nanoporous film was maintained at 9 μm. A calcination time of 12 h was found to be optimal, and the highest conversion efficiency achieved with the 9 μm film was 2.43%. The results show the power deposition in oxygen conditions successfully shortened the best low-temperature calcination time shortened from 24 hours to 12 hours. In order to further improve the conversion efficiency, the effect of film thickness on cell efficiency was investigated. The highest conversion efficiency of 3.93% was obtained at a film thickness of 21 μm in inorganic dye-sensitized. The highest conversion efficiency of 3.91% was obtained at a film thickness of 15 μm in organic dye-sensitized. The ZnO nanoporous films were prepared by using the electrochemical deposition method with oxygen bubbling in the titanium substrate, titanium has a low resistance, good flexibility and flexible features, suitable for the preparation of flexible dye-sensitized solar cells. The results showed that the photoelectric conversion efficiency of hydrogen treatment and polished, the photocurrent density and fill factor were significantly higher than the high temperature treatment and untreated. The highest back-illuminated type photoelectric conversion efficiency of 2.2% was obtained at a film thickness of 35 μm in hydrogen treatment.
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Kuo, Po-Hsiang, and 郭博翔. "Deposition of nanocrystalline TiO2 films on flexible titanium mesh for use in dye-sensitized solar cell." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/29661660258825874135.
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碩士樹德科技大學
電腦與通訊系碩士班
99
The dye-sensitized solar cell (DSSC), which has the features of low cost, flexibility and heat resistance, is one of the emerging technologies for harvesting solar energy. The components of a DSSC structure are comprised mainly of the glass substrate, transparent conductor (indium tin oxide, ITO), semiconductor material (titanium oxide, TiO2), dye, electrolyte, and cathode (platinum, Pt). The alkali-free glass substrate deposited with ITO and TiO2 films is adopted as photovoltaic electrode. On the contrary, the glass deposited with Pt film is served as the photocatalytic electrode. At present, the energy conversion efficiency of TCO glass-based DSSC has exceeded 11%. However, the ITO glass in a DSSC takes up 16-24% of the total cost. In addition, its flexibility is also poor. In this study, an efficient flexible DSSC using titanium mesh for fabricating nanocrystalline TiO2 electrode and counter-electrode were investigated. These TCO-less flexible electrodes are sintered under 550 °C and exhibit high-temperature durability. At first, several treatments against the titanium mesh were carried out for obtaining a protective layer. Then the Ti mesh was immersed into the TiO2 colloid solution and then sintered at 450 ℃ to fabricate the photoanode. The photovoltaic parameters of various DSSCs were discussed through the observations of TiO2 nanoporous thin films. With a illuminating power density of 100 mW/cm2, a flexible DSSC withη=2.19% is obtained.
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Chiu, Wan-Chi, and 邱琬琪. "Applications of hybrid nanocrystalline TiO2/Au films prepared by electrophoretic deposition on dye-sensitized solar cell." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/tr2f34.
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碩士國立虎尾科技大學
光電與材料科技研究所
98
In this study, preparation of two different methods TiO2/Au hybrid films and working on the electrode of dye-sensitized solar cell (DSSC). TiO2 thin films were prepared were by electrophoretic deposition (EPD). We used a citrate reduction method and photochemical deposition method to prepared gold nanoparticles on TiO2 thin film, respectively. Gold nanoparticles investigated by the measurements of ultraviolet-visible absorption spectra (UV-Vis) of the peaks observed at 520 nm arise from the surface plasmon resonance (SPR) in the spherical gold nanoparticles. The shape of gold nanoparticles observed by transmission electron microscopy (TEM) was spherical and the average diameter was 21 nm. The XRD pattern shows the TiO2/Au hybrid films, which primarily peaks of anatase (101), rutile (110) and Au (111). The peaks are corresponding to the FCC metallic gold diffraction. The intensity of peak were increases with increase in the size of gold nanoparticles. The surface plasma resonance of the gold nanoparticles, can efficient enhancement of photoexcitation of electrons in the dye molecules. Most importantly, this study shows that the energy conversion efficiency of DSSC with the EPD-TiO2/Au hybrid film is 3.203 %, and is guite higher than that TiO2 thin film, which is 2.877 %. From the results of I-V characteristics, the gold nanoparticles added in TiO2 thin films can effectively reduce the recombination of charges in the dye (or electrolyte). The presence of the Schottky barrier can increase the conductivity and the conversion efficiency of DSSC. However, much more gold nanoparticles added in TiO2 thin films will reduce the absorption of the dye resulting in the reduction of conversion efficiency of DSSC.
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Chen, Huang-Chin, and 陳煌欽. "Deposition of TiO2 Film using a Premixed C2H4/O2/N2 Flame and Its Preliminary Application in Dye Sensitized Solar Cell." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/75355577261878702419.
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碩士國立交通大學
機械工程學系
100
In this study, C2H4/O2/N2 premixed flat flame has been used to deposit TiO2 films by using TTIP as precursor. After 15 minutes deposition, 30 μm thick TiO2 films grow upon substrates which embedded in a rotating disk. Synthesized particles were characterized by XRD, SEM, and TEM analysis to quantify crystallinity, observe morphology, and to measure particles size and distributions. By controlling flame equivalence ratio, precursor concentration, flame height, and disk rotation frequency, the synthesized particles can reach 97 percent anatase phase. The mean particle diameters are 12 nm, with a distribution from 5 to 25 nm. Finally, using ITO glass as substrates to deposit TiO2 films and annealing at 450C for dye sensitized solar cells (DSSC) fabrication, we obtain the best cell efficiency of 2.8 percent.
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Ou, Chia-yang, and 區佳揚. "Deposition of Al-doped ZnO films by magnetron sputtering and its application in dye-sensitized solar cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/05600668527228721494.
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碩士大葉大學
電機工程學系
98
In this study, deposition of Al-doped ZnO(AZO) films by magnetron sputtering system, and applied to dye sensitized solar cells (DSSC). It can be divided into two parts. The first part is mainly to explore the process parameters of magnetron sputtering system to deposit AZO thin film. Using FE-SEM, XRD, Hall-effect, UV-VIS to analyze the optical and electrical properties of AZO thin films. The experimental results show: when working pressure in 2×10-3torr、subtract temperature in 325℃,the resitivity is 2.9401×10-4(Ω．cm), and concentration is 3.2599×1021(cm-3), and mobility is 6.4682 (cm2．V-1．S-1). It can further enhance the electric conductivity of AZO, when it in 550 ℃ under an Ar/H2 (6%) atmosphere of annealing for one hour.The resitivity is 2.0176×10-4(Ω．cm), and concentration is 2.7939×1021(cm-3), and mobility is 11.08518 (cm2．V-1．S-1). After deposited AZO thin films, we using hydrochloric acid to etch the surface of AZO thin films. Using UV-VIS, Four-Point Probe, Haze meter, FE-SEM, to analyze the electrical and optical properties of AZO thin films. The second part ,we use AZO transparent conductive glass substrate in the first part, and it will be applying to DSSC. Using Degussa P25 TiO2 to spin coating(8.6μm) under AZO thin film for the photo-electrode, then we sinter the photo-electrode in 450℃. Our DSSC uses D719 dyes, EL-100 electrolytes and Pt counter-electrode. We measured the photovoltaic conversion efficiency(simulated AM 1.5 sunlight), and the result shows: Voc=0.8519 V、Jsc=4.460 mA/cm2、FF=0.53、η=2.009%.
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Lin, Shih-Heng, and 林仕恆. "Study of Dye Sensitized Solar Cell Application of TiO2 Films by Atmospheric Pressure Plasma Jet Deposition System." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/84879083632112583666.
Full textAbstract:
碩士義守大學
材料科學與工程學系
101
The purpose of this work is to use a self-developed low temperature atmospheric pressure (AP) plasma system with metal- plasma electrodes to deposit titanium dioxide (TiO2) film on indium doped tin oxide (ITO) conductive glass as dye-sensitized solar cell of the photo-anodes. N719 dyes as well as the iodine ions electrolyte were served as the dye-sensitized solar cell (DSSC) components, and the DSSC devices were analyzed by I-V meters to determine the photovoltaic conversion efficiency. In the film deposition studies of experimental parameters, mainly included such as the coating working distances, the precursor inlet angles, the air compressor pressures, the plasma powers, the deposition temperatures, the deposition times and the precursor flow rates and so on. Obtain optimization of the deposition parameters to achieve effective control of the film thickness and morphology, and to enhance the dye adsorption capacity and photoelectric conversion efficiency. Through a series of experiments showed the optimal experimental parameters are the deposition temperature of 500℃, the precursor flow rate of 75 sccm, the output power wattage of 330W and the deposition time of 5 minute, and the photoelectric conversion efficiency could up to 6.407%. In this study, the optimum process parameters produced films with a high specific surface area of titanium dioxide nanoparticles (TNPs) and well vertical-aligned titanium dioxide nano-rods (TNRs) morphology, which can significantly improve the photoelectric conversion efficiency.
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Chen, Wei-Ting, and 陳維婷. "Applications of nanocrystalline TiO2 and ZnO films prepared by electrophoretic deposition on flexible dye-sensitized solar cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/62697d.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
98
Because electrophoretic method (EPD) has the advantage of high-speed deposition and low-temperature production suitable for plating film material, we use this method to make the thin film electrode of TiO2 and ZnO. Utilizing EPD to manufacture TiO2 and ZnO thin film can improve nano thin film structure. This method is applied to production of high-efficiency dye-sensitization solar cells. The paper research of EPD method was popularly used when making the thin film electrode of TiO2 and ZnO. We analyzed the XRD to dissect a titanium dioxide nanoparticles to deposite on the thin-film by EPD. The crystallization of thin film is the anatase phase, while the same anatase phase after compression. The crystallization of zinc oxide is better, and the relative diffraction intensity is stronger. UV-Vis spectrophotometer analysis can tell the situation of N3 dye adsorbing on the thin films of TiO2 and ZnO; the absorption wavelength obviously promotes from the ultraviolet ray to the visible light scope, and this has great help toward the electro-optic transfer efficiency. Efficiency aspect, the compressed TiO2 thin films have the best energy conversion efficiency when thickness is 1.7μm. VOC = 0.74V, JSC = 6.96 mA, F.F =53, η=2.73%. The thinner thickness of compressed thin film is helpful to the reduction of electron transfer way, and reduces resistance and increases adsorbability toward dye relatively. However, the efficiency of zinc oxide thin film after compression becomes worse due to disarrangement of its structure, hole reduction on thin film structure, and disordered pileup format of reuniting dye molecules. Above reasons lead to the deactivation of electron-injection efficiency and the loss of current, thus compressed ZnO thin film reduces the cell efficiency.
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Kang, Tz-Hung, and 康子鴻. "Applications of multilayer nanocrystalline TiO2 thin films and scattering layer prepared by electrophoretic deposition on dye-sensitized solar cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/q7cf27.
Full textAbstract:
碩士國立虎尾科技大學
光電與材料科技研究所
98
The study is mainly to discuss that the effects of multilayer nanocrystalline TiO2 thin films and scattering layer prepared by electrophoretic deposition (EPD) on the performance of the dye-sensitized solar cells (DSSCs). In the field emission scanning electron microscopy (FE-SEM) analysis, TiO2 thin films prepared by EPD have the porous structure. The porous structure is advantageous in the dye-loading capacity. And used multilayer nanocrystalline TiO2 thin films prepared by EPD, the cracks can improved on the thin films surface. When added scattering layer in DSSCs, it can increase the path length of the incident light in the nanocrystalline TiO2 thin films. From the results of XRD analysis, the strong crystallization of TiO2 thin film is the anatase phase. UV-Vis spectrophotometer analysis can tell the situation of N3 dye adsorbing on the TiO2 thin films; the absorption wavelength obviously promotes from the ultraviolet ray to the visible light scope, and this is great help for conversion efficiency of DSSCs. Under the irradiation of the sunlight simulator (AM 1.5, 100 mW/cm2), the energy conversion efficiency of DSSCs with the TiO2 thin films is 3.243%. In the electrochemical impedance spectroscopy (EIS) analysis, the value of Rk decreases with increasing the thickness of TiO2 thin films, the primary cause is related with the dye adsorptive capacity. It may be due to the stimulation of illumination for the electron in the dye, resulting in the reduced of the Rk.
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Cheng, Chao-Kuang, and 鄭照光. "Electrochemical deposition of molybdenum sulfide thin film on conductive plastic substrate as a platinum-free flexible counter electrode for dye-sensitized solar cells." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/n59hsu.
Full textAbstract:
碩士明志科技大學
材料工程系碩士班
103
In this work, the pulses electrochemical deposition (pulses-ECD) method was used to deposit the molybdenum sulfide (MoSx; x= 2, 3) thin films onto the indium tin oxide/polyethylene naphthalate (ITO/PEN) substrates as a flexible counter electrode (CE) for dye-sensitized solar cells (DSSCs). The surface morphologies and the elements within the sampling volume of the prepared MoSx thin films were examined by field emission scanning electron microscope (FE-SEM) equipped with an energy-dispersive X-ray spectroscopy (EDX). The chemical states and the crystallinity of the prepared MoSx thin films were examined by the X-ray photoelectron spectroscopy (XPS) and the X-ray diffraction (XRD) technology, respectively. The optical transmission (T %) properties of the prepared MoSx samples were determined by a UV-Vis spectrophotometer. The cyclic voltammetry (CV) and Tafel-polarization were analyzed by a potentiostat/galvanostat to examine the electrochemical properties of the catalytic activities for the redox reactions. The FE-SEM results showed that the MoSx thin films were deposited uniformly on the ITO/PEN flexible substrates via the pulses-ECD method. The measurements of CV and Tafel-polarization curves demonstrated that the pulses-ECD MoSx thin films exhibited an excellent triiodide ions reduction performance. The photoelectric conversion efficiency (PCE) of the DSSC with the pulses-ECD MoSx thin films CE was examined by a solar simulator. In combination with a dye-sensitized TiO2 working electrode and an iodine-based electrolyte, the DSSC with the MoSx flexible CE. showed a PCE of 4.39% under the illumination of AM 1.5 (100 mWcm-2). Here we report that MoSx thin films are active catalysts for triiodide reduction. The MoSx thin films are prepared at room temperature and atmospheric pressure, and in a simple and rapid manner. This is an important practical consequence on the production of flexible low-cost thin film counter electrode based on the plastic substrate. The methods demonstrated that the pulses-ECD MoSx thin films played a good catalytic candidate for the flexible DSSCs.
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Tsai, Meng-Chia, and 蔡孟家. "Study of Dye Sensitized Solar Cell Application of ZnO and AZO Thin Films Deposition by Atmospheric Pressure Plasma Jet System." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/84024641653635403594.
Full textAbstract:
碩士義守大學
材料科學與工程學系碩士班
98
The purpose of this study is to investigate the deposition processes and dye-sensitized solar cell (DSSC) applications of zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) films by our lab self-designed low-temperature atmospheric pressure (AP) plasma jet system. The research items can be mainly divided into AP plasma jet system hardware improvement and novel deposition processes, and the objective is to achieve the mass production stability and high DSSC conversion efficiency. Firstly, try to find out the optimal deposition processes of ZnO and AZOthick films, investigate the porosity, conductivity and transparency of films and their effects on the DSSC conversion efficiency. Subsequently, adopt HCl wet-etching and oxygen plasma surface treatment processes to produce more porosity and polar functional groups, respectively, try to study the influences of porosity and functional groups on the dye absorption and DSSC conversion efficiency. The experimental results indicated that the optimal deposition processes of ZnO and AZO films for main argon flow rate/ precursor flow rate/ oxygen flow rate/ substrate temperature are 8slm/ 210sccm/ 20sccm/ 375oC and 8slm/ 220sccm/ 30sccm/ 375 oC, respectively. Meanwhile, deposited the optimal ZnO and AZO films for 15 minutes, revealed the conversion efficiencies of ZnO and AZO films DSSC devices are 0.269% and 0.099%,respectively. However, the HCl wet-etching and oxygen plasma surface treatment processes resulted in low dye absorption and low DSSC conversion efficiency.
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Lu, Kuo-Kai, and 呂國楷. "Study of Dye Sensitized Solar Cell Application of TiO2 and ZnO Composite Films by Atmospheric Pressure Plasma Jet Deposition System." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/87698487275380233672.
Full textAbstract:
碩士義守大學
材料科學與工程學系碩士班
99
The purpose of this work is to develop a novel low temperature atmospheric pressure (AP) plasma system with quartz glass and metal electrodes and to use the system to deposit titanium dioxide film and zinc oxide film on indium doped tin oxide (ITO) conductive glass as dye-sensitized solar cell of the working electrodes. Rose bangle and N719 dyes as well as the iodine ions electrolyte were served as the dye-sensitized solar cell (DSSC) components. In the deposition processes, the variations of deposition temperatures for formation titanium dioxide and zinc oxide films can be optimized to enhance the adsorption capacity of dyes by selecting reasonable surface morphology. The role of zinc oxide in the DSSC device is to increase the surface roughness and energy level, it could result in increasing the dye adsorption and reducing the opportunity of electron-hole recombination, to enhance the photovoltaic conversion efficiency. Experimental results showed that the working electrode synthesized by quartz glass electrode included the first layer with petal-like zinc oxide film at a deposition temperature of 270oC and the second layer with porous titanium dioxide at a deposition temperature of 500oC and an oxygen flow rate of 200sccm, the photovoltaic conversion efficiency can reach to 1.01 %. In metal electrode, the single porous titanium dioxide layer with a precursor flow rate of 75sccm, the photovoltaic conversion efficiency can reach to 1.71%. Combine two kinds of the electrodes, the working electrode was fabricated on fluorine-doped tin oxide (FTO) conductive glass included the first layer with high crystalline titanium dioxide was deposited by quartz glass electrode and the subsequent second layer with porous titanium dioxide by metal electrode, the best photovoltaic conversion efficiency can reach to 2.60%.
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Chen, Wei-An, and 陳韋安. "Fabrication TiO2 Thin Films in Dye-Sensitized Solar Cells by Electrophoresis Deposition and Research of the Natural dye Characteristic Analysis." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/729kbh.
Full textAbstract:
碩士國立臺北科技大學
製造科技研究所
96
The Dye-Sensitized Solar Cell is being paid attention by the researcher because of material is cheap. Since issuing abroad, efficiency has been also improved constantly. There are many study develop for layers of the sandwich structure. However, they are often pursuing high efficiency with equipment of consume energy and rare element. This research use electrophoresis deposition (EPD) method in photo-electrode of DSSC and analysis the characteristic of natural dye. First part, we controlled colloid (TiO2 /IPA) of EPD suspend stable. The result of experimental indicate TiO2/IPA could suspend when it mixed suitable Mg(NO3)2．6H20. These optimum parameters of EPD indicate that electric field intensity 40V/cm could get roughness of thin film about 1005.725Ǻ. After, we assemble the photo-electricity to the sandwich structure of DSSC. We controlled after-treatment include thermal treatment under various method and application multilayer to improve crack. TiO2 layers increase the absorbing amount of dye molecule, and then improve the density of photocurrent to 12.2mA/cm2. On the side, the development of flexible DSSC, experiment photo-electricity used low temperature colloid solution and multilayer electrophoresis coating on ITO/PET. The second part is to analyze ingredient of natural dye and their character in DSSC. Results of experiment, Ingredient analyze with UV-vis spectrum, contained chlorophyll –α and β—carotene. By the method of IPCE (incident photon-to- electron conversion efficiency), we analyzed that the chlorophyll –α had characteristic of sensitization, but β—carotene hadn’t. Although β—carotene hadn’t sensitization characteristic, they could release energy to electron that caught by TiO2 surface trap. Thus, electron could return to conduction band again. The natural dye that involving β—carotene lengthen electronic lifespan cycle.
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Su, Siang Tai, and 蘇湘太. "Using Pulsed Laser Deposition for Growing TiO2 Mesoporous Films with Structures Optimized for Increasing the Efficiency of Dye-Sensitized Solar Cells." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/03720793699214376240.
Full textAbstract:
碩士國立中正大學
物理學系暨研究所
101
Growth of nanostructured anatase TiO2 thin film with pulsed laser deposition and post annealing： - Increasing the specific surface area while with appropriate pore size by producing the particles with nanometer-scale sizes (20 ~ 30 nm). - Producing nanometer-scale (~ 10 nm) canals within TiO2 thin film. - Enhancing the crystallinity (anatase) of TiO2 thin film. - Increasing the electromechanical bonding between TiO2 nanoparticles.
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Wu, Yurun, and 吳侑潤. "Study Of Dye Sensitized Solar Cell And Electrochromic Deviced Application Of TiO2 Doped ZnO Films By Atmospheric Pressure Plasma Jet Deposition System." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/13023515024031069663.
Full textAbstract:
碩士義守大學
材料科學與工程學系
100
The purpose of this work is to use a self-developed low temperature atmospheric pressure (AP) plasma system with quartz glass- and metal- plasma electrodes to deposit titanium dioxide (TiO2) doped with zinc oxide (ZnO) film on indium doped tin oxide (ITO) conductive glass as dye-sensitized solar cell of the photo-anodes. N719 dyes as well as the iodine ions electrolyte were served as the dye-sensitized solar cell (DSSC) components, and the DSSC devices were analyzed by I-V meters to determine the photovoltaic conversion efficiency. Simultaneously, the films electrochromic properties were studied by the cyclic voltammetry. In the deposition process, it was revealed that the variations of air-compressor pressures and plasma wattages would result in the effective reduction in the films thickness and morphologies. In the deposition of TiO2 doped with ZnO films processes, it was found the film thicknesses increased and porosities decreased as the zinc oxide doping increased. However, the un-doped TiO2 films revealed porous morphologies, and resulted in more dyes absorption and higher photovoltaic conversion efficiency. Under the plasma wattage of 286W with the deposition times of 3 min and 5.5 min, the photovoltaic conversion efficiencies could reach to 2.711% and 4.455%, respectively. The best photovoltaic conversion efficiency could reach to 6.44% by using FTO substrate to replace ITO substrate under the same optimized process parameters. The electrochromic experimental results indicated that the TiO2 films possessed reasonable colouring and bleaching characteristics for the precursor flow rate of 75sccm, the plasma wattage of 154W and the deposition time of 30sec, with argon and oxygen flow rates of 7slm and 200sccm, respectively.
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Fotsa-Ngaffo, Fernande. "Reactive pulsed laser ablation deposition (RPLAD) of indium tin oxide (ITO), titanium dioxide (TiO2) thin films and gold (AU) nanoparticles for dye sensitised solar cells (DSSC) applications." Thesis, 2008. http://hdl.handle.net/10539/4615.
Full textAbstract:
ABSTRACT
The focus of this work was the study possible ways to improve the efficiency of solar cells. To this end, the main aim was to investigate the deposition process of Indium Tin Oxide (ITO), Titanium Dioxide (TiO2), multi-layers ITO/TiO2 on quartz SiO2 substrates under different conditions (oxygen pressure, laser fluence and wavelength, and temperature) and later gold nanoparticles by the Reactive Pulsed Laser Ablation Deposition (RPLAD) technique. It was intended to investigate their electrical structural and optical properties under selected conditions for possible application to Dye Sensitised Solar Cells (DSSC).
Under optimised conditions, maximum deposition rates of 12nm/min for ITO and 21nm/min for TiO2 thin films were achieved. Rutherford Backscattering Spectrometry (RBS) with 2MeV He+ ions was used to measure the films thickness. Uniform thicknesses over a large area were found to be about 400nm and 800nm for ITO and TiO2 films, respectively. Crystalline properties were studied via x-ray diffraction and Raman spectroscopy. X-ray Diffraction (XRD) analysis revealed that the ITO films are highly orientated nanocrystals with their a-axis normal to the glass substrate surface. The average particle size of the precipitated nanocrystals was calculated to be 10-15nm.
The structure of the films was characterised via Atomic Force Microscopy (AFM) imaging of the top surface of the film. The films have a rough surface with average roughness of 26-30nm. Pores were observed with a density of 144 and 125 pores/mm2 and average size of 150 and 110nm for ITO films deposited at 200 and 400°C, respectively. TiO2 films deposited on the prepared ITO films were less crystalline. Annealing was performed at 300 and 500°C for 3 consecutive hours and the XRD results show that the transformation of TiO2 film into anatase phase was almost complete with a crystal size of ~ 6-7nm.
Scanning Transmission Electron Microscopy (STEM) of the surfaces was also performed. The TiO2 films deposited onto the prepared ITO films present a
relatively high pore size with an average pore diameter of ~ 40nm and excellent uniformity. It is interesting to note that the pores are randomly arranged. The random arrangement of the pores network may actually be beneficial for producing a uniform electrode. In addition, STEM cross-sectional analysis of the films showed a columnar structure but no evidence of voids in the structure. The large surface area produced suggests applications in DSSC.
The electrical properties of the films were investigated and an estimation of resistivity and Hall mobility was made. Low values of resistivity and high values of mobility were observed for ITO films. The resistivity of the film increases with increasing thickness while it decreases when increasing the deposition temperature. The lowest value was found to be 1.5x10-6Ωm for ITO films deposited at 400°C. Hall mobility was found to increase with substrate temperature. In this investigation, the highest Hall mobility at room temperature was estimated to be 22.3cm2/Vs under ambient O2 pressure (PO2) of 1Pa and 52.1 and 51.3cm2/Vs for films deposited at 200 and 400°C, respectively. But the best ITO film was deposited at 200°C, since this film combines good resistivity, good Hall mobility and good transmittance.
UV-VIS-IR transmission spectra were recorded on a Perkin Elmer Lambda 900. From the transmission data, the energy gap as well as the optical constant was estimated. A high transmission for ITO films in the visible (Vis) range was observed which was above 88% for films produced at room temperature and above 95% for those deposited at 200°C. The transmission for the films produced in oxygen was about 90% above 400nm, whereas it lies between 70 and 80% for films produced in rare gases. An increase in the band gap was observed by increasing the oxygen pressure and substrate temperature for ITO films. Increasing the quartz SiO2 substrate temperature from room temperature to 400 °C resulted in an increase of the transmission of TiO2 films, mostly in the Visible Near Infrared (Vis-NIR) from about 70% to 92%. After annealing at 500°C for 3 consecutive hours, the transmission of TiO2 film further sharply decreases toward shorter wavelengths.
Analysis of the transmittance curve of TiO2/Au shows a decrease of about 6% of the transmission in the Ultraviolet Visible (UV-Vis) range.
Optical absorption edge analysis showed that the optical density could be used to detect the film growth conditions and to correlate the film structure and the absorption edge. The TiO2 films deposited present a direct band gap at 3.51eV and 3.37eV for TiO2 as deposited and after annealing, respectively, while the indirect band gap was found to be 3.55eV and 3.26eV for TiO2 films as deposited and after annealing, respectively. There was a shift of about 0.1eV between as deposited ITO monolayer films and ITO/TiO2 bilayers deposited at 200°C. A small shift towards shorter wavelengths has been observed for multilayer ITO/TiO2/Au. In this case, the increase of Eg was ascribed to a reduction of the oxygen vacancies with increasing substrate temperature at which the ITO film was deposited.
The change in the shape of the fundamental absorption edge is considered to reflect the variation of density and the short range structural modifications undetected by structural characterisations. Enlargement of band-gap energies of semiconductors may be advantageous when used in DSSC to suppress the charge recombination between the reduced electrolytes and the photo-excited holes in the valence band of TiO2 substrates and enhance the open-circuit potential of the cell. When ITO/TiO2 bilayers were annealed before depositing Au, the gap energy remained constant.
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吳稚偉. "1. Deposition of InN Nanoparticles on TiO2 Films for Dye-Sensitized Solar Cell and Photoluminescene Studies 2. Shock Tube Study on the Thermal Decomposition of Ethanol." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/43116069138236335314.
Full textAbstract:
博士國立交通大學
應用化學系碩博士班
100
Part 1: Deposition of InN Nanoparticles on TiO2 Films for Dye-Sensitized Solar Cell and Photoluminescene Studies The direct deposition of InN over TiO2 nanoparticle and nanotube (NP and NT) films was demonstrated by employing a plasma-enhanced chemical vapor deposition (PECVD) system with trimethyl indium (TMIn) and ammonia (NH3) as indium and nitrogen precursors, respectively. By varying the flow rate of TMIn at 358 K, enhancement in power conversion efficiencies by 4-23% and 1-11% under AM 1.5 illumination was observed for N3 dye sensitized solar cells using the InN deposited TiO2 NP and NT films, respectively. With a 9 μm thick TiO2 substrate, the most improvement of conversion efficiency increased from 6.57% to 8.20% by using 2 sccm of TMIn and 20 sccm of NH3 at 358 K for 10 min InN deposition on the TiO2 NP film. The enhancement by InN deposition can be explained by the improved absorption in the range of 400-500 nm and the increased loading of N3 dye molecules. This study describes the noticeable improvement of DSSC efficiencies by semiconductor nanoparticles deposited on TiO2 NP films. The enhancement of photoluminescence (PL) from anatase TiO2 thin films covered with InN nanoparticles by PECVD can also be observed. The strong PL band observed in the anatase TiO2 thin films with the coated InN may be attributed to the special interface of InN/O and/or more defects generated during the deposition. Part 2: Shock Tube Study on the Thermal Decomposition of Ethanol The thermal decomposition of C2H5OH highly diluted in Ar (1-100 ppm) has been studied by monitoring H atoms using the atomic resonance absorption spectrometry (ARAS) technique behind reflected shock waves over the temperature range 1308 - 1760 K at pressures: 1, 1.46 and 2 atm. Branching fractions for producing CH3+CH2OH (1a) and H2O+C2H4 (1b) have been examined by quantitative measurements of H atoms produced in the secondary decomposition of the product CH2OH; the pressure dependence of the branching fraction for channel (1a) is obtained by a linear least-squares analysis of the experimental data and can be expressed as f1a = (0.71±0.07) - (826±116)/T, (0.90±0.02) - (1079±34)/T, (1.02±0.10) - (1229±168)/T at P = 1, 1.46 and 2.0 atm, respectively, for T = 1450 - 1760 K. The rate constant obtained in this study is found to be consistent with previous theoretical and experimental results; however, the pressure dependence of the branching fraction obtained in this study is smaller than those of previous theoretical works. The experimental k1 and f1a can be summarized as follows: k1a/s-1 = F1a(6.07±0.18) x 10^10 exp[-(23850 ± 750)/T] k1b/s-1 = (1-F1a) (6.07±0.18) x 10^10 exp[-(23850 ± 750)/T] where, F1a is given by, F1a = (0.308P+0.420) – (399P+451)/T. The observed evolutions of [H], [CO] and [H2O] with time, together with the recent experimental and theoretical results on the kinetic parameters of the important related elementary reactions have been used to construct an extended reaction model for the pyrolysis of C2H5OH and compared with the previously proposed kinetic models.
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Hung, Chun-cheng, and 洪俊丞. "Study of Dye Sensitized Solar Cell Application of TiO2 and ZnO Thin Films Doped ZrO2 and SnO2 Deposition by Low Temperature Atmospheric Pressure Plasma Jet System." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46614659032181227303.
Full textAbstract:
碩士義守大學
材料科學與工程學系碩士班
97
Energy requirements become larger is due to the technology development, meanwhile, energy crisis will happen as the energy are depleted gradually. Recently, solar cell technology is popularly considered and developed again to provide the energy, and dye-sensitized solar cells (DSSCs) may be served as the new generation of organic solar cells for possessing high competitiveness with low-cost, easy assembly and high throughput priorities. The purpose of this work is to use the self-developed low temperature atmospheric pressure (AP) plasma system, and deposit TiO2 thin film and ZnO thin film doped ZrO2 and SnO2 thin film on indium-tin oxide (ITO) substrates as the working electrode of dye-sensitized solar cell. The rose bangle dyes and iodine ions electrolyte are also used to in the formation of DSSC solar cell devices. IV test station is adopted to measure the photo-electric conversion efficiency. In the deposition experiment, the reasonable surface morphologies and dyes adsorption of titanium dioxide and zinc oxide thin films are achieved by varying the deposition temperatures. The roles of tin dioxide and zirconium dioxide in the working electrodes are to enhance the absorption of visible light spectrum and decrease the reverse current in DSSC devices, respectively. The optimal processing parameters in tin oxide and zirconium dioxide thin films deposition are pursued by changing the precursors and oxygen gas flow rates. Subsequently, we use the optimal processing parameters to perform the doping processes. The doped working electrodes are used to form DSSC devices and predicted to achieve higher photo-electric conversion efficiency. Experimental results show that the optimum deposition parameters of tin oxide for the precursor and oxygen gas flow rates are equal to 100sccm and 200sccm, respectively. While, the optimum deposition parameters of zirconium dioxide for the precursor and oxygen gas flow rates are equal to 80sccm and 200sccm, respectively. ZnO thin films possess high surface roughness at the temperature of 300oC, and its photo-electric conversion efficiency can reach the highest value of 0.3%. However, titanium dioxide thin film has a high surface roughness at high temperature, and the maximum photo-electric conversion efficiency can be achieved to 0.06%. Although the photo-electric conversion efficiency is very low, it may become to the application reference of a thin-film-type DSSC device.