Dissertations / Theses on the topic 'Solar cell, dye, DSSC, impedance'
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DELL'ORTO, ELISA CAMILLA. "Dye sensitized solar cells: materials and processes." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2012. http://hdl.handle.net/10281/28476.
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During the thesis the DSSCs optimization was analyzed mainly through two strategies: the study of new sensitizers and the study
of alternatives materials for photo-cathode fabrication.
Two class of sensitizers were be analyzed: squaraine dyes and cyclometalated-based dyes. Then a study on dye-loading process will be presented, with implication in an industrialization process. For the photo-cathode fabrication two di erent materials were studied, a carbon based material and a polymeric material.
Then a part of the work concerned the study of devices analysis system. In particular electrochemical impedance spectroscopy was
studied to propose a new set up to analyze electric processes in different cell components.3
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Gong, Yun. "Structure-property relationships of dyes as applied to dye-sensitized solar cells." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275007.
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This work investigates the correlation of structural and photovoltaic properties of dyes used in dye-sensitized solar cells. Experimental methods, including ultraviolet-visible spectroscopy, fluorescence spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy are employed to study optical and electrochemical properties of dye molecules. Computational methods, including density functional theory and time-dependent density functional theory, are used to validate and predict the optical and electronic properties of dye molecules, in their isolated state and once embedded into a working electrode device environment that comprises a dye...TiO2 interface. The results chapters begin with the presentation of a series of quinodimethene dyes that are experimentally validated for their photovoltaic application, and associated computational studies reveal that an inner structural factor - a phenyl ring rotation occurring during the optical excitation process - leads to the competitive photovoltaic device performance of these dyes. Carbazole-based dyes are then systematically studied by computation, especially considering charge transfer paths and binding modes of these dyes on a titania surface. The theoretical models for the basic building block of this chemical family of dyes, known as MK-44, successfully support and explain structural discoveries from X-ray diffraction and reflectometry that impact of their function. A benzothiadiazole-based dye, RK-1, is then systematically studied by both experimental and computational methods, and the results show that the π-bridge composed of thiophene, benzothiadiazole and benzene rings leads to excellent charge separation; and the rotation of these rings during the optical excitation process may well be consistent with the fluorescence spectrum. Finally, the well-known ruthenium-based dyes are theoretically studied to determine the properties of different ligands connected to the metal core of the complex. Conformations with different NCS ligands are calculated in terms of energy and explain well the corresponding results from X-ray diffraction. Acid-base properties of carboxyl groups connected to pyridine ligands in N3 and N749 are theoretically calculated based on thermodynamics and density functional theory. Implicit and explicit models are both adopted to predict these acid dissociative constant values, which are generally in a good agreement with the reported experimental data. The thesis concludes with conclusions and a future outlook.
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Henek, Tomáš. "Charakterizace vlastností perovskitovských fotovoltaických článků." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-376942.
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This work studies the subject of perovskite solar cells. The structure of perovskites is described along with a portion of photovoltaics history that led to the employment of perovskites as absorpsion layers. Further, methods of measurement for solar cells such as impedance spectroscopy, photospectroscopy and load characteristics are summarized. Lastly there is a description of already done analytics of perovskite solar cells with the summary of the results. In the practical part, there are measurements made to find out any effect of cell topology or light source wavelength on the cell performance.
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Li, Sin-lai Emily, and 李倩麗. "Theoretical study of dye-sensitized solar cell (DSSC)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B41897195.
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Li, Sin-lai Emily. "Theoretical study of dye-sensitized solar cell (DSSC)." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B41897195.
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Falsgraf, Erika S. "Biologically-Derived Dye-Sensitized Solar Cells: A Cleaner Alternative for Solar Energy." Scholarship @ Claremont, 2012. http://scholarship.claremont.edu/pomona_theses/61.
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This project employs the biological compounds hemin, melanin, and retinoic acid as photoactive dyes in dye-sensitized solar cells (DSSCs). These dyes are environmentally and economically superior to the standard ruthenium-based dyes currently used in DSSCs because they are nontoxic and widely available. Characterization by linear sweep voltammetry yielded averaged maximum overall conversion efficiency values of 0.059% for retinoic acid, 0.023% for melanin, and 0.015% for hemin. Absorption spectra of hemin and retinoic acid suggest that they would complement each other well when used in tandem in one cell because hemin has a secondary maximum absorption peak at 613nm and retinoic acid has maximum absorption at 352nm. Cells made with hemin or melanin performed better with the use of lower temperatures to seal the cells, and hemin cells performed exceptionally well with exclusion of the sealing procedure. These biologically-derived cells have the potential to advance the development of inexpensive and safer solar energy sources, which promise to serve as clean energy sources in the near future.
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Yu, Cheng-Lun. "Titanium dioxide thick film printing paste for dye sensitized solar cell." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1291216520.
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Zhang, Jian. "INVESTIGATION OF THE EFFECTS OF LAYER THICKNESS ON DYE SENSITIZED SOLAR CELL PERFORMANCE." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1377132624.
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Giray, Hasan Berk. "The Effects Of Platinum Particle Size To The Efficiency Of A Dye Sensitized Solar Cell (dssc)." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611577/index.pdf.
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The aim of this study was to modify the platinum particle size to observe the effects on the efficiency of a Dye Sensitized Solar Cell (DSCC). DSSC was prepared as follows: On the anode side, TiO2 was annealed on the transparent conducting oxide (TCO) which is SnO2:F coated and a cis-bis (isothiocyanato) bis (2,2'-bipyridyl-4,4'
-dicarboxylato)&ndash
ruthenium(II) dye was adsorbed on the TiO2. On the cathode side, platinum was coated on TCO from an alcohol based solution of platinum (plasitol) by thermal decomposition method. Potassium iodide and iodine were dissolved in ethylene glycol to prepare the electrolyte. Four cathode surfaces were prepared by thermal decomposition method at 400 oC and 5 min. Cathode surface morphology was changed by changing the annealing conditions. Current-voltage measurements were performed for determining the cell efficiency. One cathode glass was used as such giving a cell efficiency of 2.36%. Three glasses were further thermally treated at 450 oC, 500 oC and 550 oC for 30 min. highest efficiency was measured with the counter electrode annealed at 550 oC for 30 min as 2.89%. SEM micrographs of the substrate which was SnO2:F coated TCO revealed a decrease in average surface particle size with an increase in annealing temperature. EDX mappings showed that as the annealing temperature increased, Pt particles segregated together to form porous patches. In this study, it was demonstrated that as the annealing temperature of cathode increased, DSSC efficiency increased. These results can be used to design cheaper DSSCs with higher efficiencies.
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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.
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Nissfolk, Jarl. "Charge Transport Processes in Mesoporous Photoelectrochemical Systems." Doctoral thesis, KTH, Organisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9849.
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During the last decade, the dye sensitised solar cell (DSC) has attracted much attention. The technology has a potential to act as a new generation of photovoltaic device, it has also increased our knowledge within the field of photoelectrochemistry. The materials used in the DSC have been used in other technologies, such as electrochromic displays. This thesis examines how such systems can be analysed to understand their properties from their components. Both of the considered device technologies consist of a thin mesoporous semiconductor film immersed in an electrolyte. The study starts by investigating some of the fundamental properties of the mesoporous semiconductor and its interface with the electrolyte. This gives rise to the charge-voltage relationship for the devices, which is related to the chemical capacitance and electronic energy levels for the materials. In particular,special attention is given to the DSC and the properties of the charge carriers in the semiconductor. For the DSC, several techniques have been developed in order to understand the processes of transport and recombination for the charge carriers in the semiconductor film, which are vitally important for performance. In this thesis, particular focus is given to light modulation techniques and electrical analysis with impedance spectroscopy. The transportproperties show for both techniques a nonlinear behaviour, which is explained with the trapping model. The DSC solar cell is analysed in order to interpret the transport measurements for film thickness optimisation. DSC cells with new semiconductor materials, such as ZnO, were analysed with impedance measurements to provide new insights into the optimisation of the performance of the photoelectrochemical solar cell technology.QC 20100804
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Xu, Chenzhi. "Optical Spectrocopy on Nanostructrured Materials." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174866.
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Solar cells are designed to transform the optical energy into electrical energy. Using solar energy is the best way for humans to solve the energy shortage problem. Dye sensitized solar cell(DSSC) has a low cost and helps people to obtain the solar energy expediently. The DSSC is based on nano structured TiO2 ; and dye molecules help the particles of TiO2 to absorb more photons. Hence DSSC has higher efficiency than SC(solar cell without dye). This thesis elaborates and analyzes the dye which is sensitized to TiO2. The absorption spectrum of the dye was achieved. Two kinds of dye sample were made on the basis of their places in structure of TiO2. One dye sample is solution, nanopowder of the dye in aceton. The other dye sample is film, thin film on a quartz plate. The absorption spectrums of the samples have been measured in laboratory. The measurement suggests that the dye works improves the absorption of solar energy in DSSC. This thesis mainly contains the following sections: Chapter I reviews the solar energy technology development, the research purposes, and the principles of DSSC. Chapter II introduces the theory of optical spectroscopy. Chapter III and Chapter IV describe the apparatus employed in this experimental system, the experimental method, and the testing results. Chapter V gives the conclusions drawn from the experiments.
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Besharat, Zahra. "Adsorption of molecular thin films on metal and metal oxide surfaces." Doctoral thesis, KTH, Materialfysik, MF, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-195613.
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Metal and metal oxides are widely used in industry, and to optimize their performance their surfaces are commonly functionalized by the formation of thin films. Self-assembled monolayers (SAMs) are deposited on metals or metal oxides either from solution or by gas deposition. Thiols with polar terminal groups are utilized for creating the responsive surfaces which can interact electrostatically with other adsorbates. Surface charge effects wetting and adhesion, and many other surface properties. Polar terminal groups in thiols could be used to modify these factors. Mixed SAMs can provide more flexible surfaces, and could change the resulting surface properties under the influence of factors such as pH, temperature, and photo-illumination. Therefore, in order to control these phenomena by mixed polar-terminated thiols, it is necessary to understand the composition and conformation of the mixed SAMs and their response to these factors. In this work, mixtures of thiols with carboxylic and amino terminal groups were studied. Carboxylic and amino terminal groups of thiol interact with each other via hydrogen bonding in solution and form a complex. Complexes adsorb to the surface in non-conventional orientations. Unmixed SAMs from each type, either carboxylic terminated thiols or amino terminated thiols are in standing up orientation while SAMs from complexes are in an axially in-plane orientation. Selenol is an alternative to replace thiols for particular applications such as contact with biological matter which has a better compatibility with selenol than sulfur. However, the Se-C bond is weaker than the S-C bond which limits the application of selenol. Understanding the selenol adsorption mechanism on gold surfaces could shed some light on Se-C cleavage and so is investigated in this work. Se-C cleavage happens in the low coverage areas on the step since atoms at steps have lower coordination making them more reactive than atoms on the terraces. Another area where the self-assembly of molecules is of importance is for dye sensitized solar cells, which are based on the adsorption of the dye onto metal oxides surfaces such as TiO2.The interface between the SAM of dye and the substrate is an important factor to consider when designing dyes and surfaces in dye sensitized solar cells (DSSCs). The quality of the self-assembled monolayers of the dye on the TiO2 surface has a critical influence on the efficiency of the DSSCs. Creation of just a monolayer of dye on the surface could lead to an efficient current of photo-excited electrons to the TiO2 and degeneration of the dye by redox. This work, T-PAC dye showed island growth with some ad-layer that is not in contact with the surface, whereas the MP13 dye adsorption is laminar growth. Cuprite (Cu2O) is the initial and most common corrosion product for copper under atmospheric conditions. Copper could be a good replacement for noble metal as catalysts for methanol dehydrogenation. Knowledge about the structure of Cu2O(100) and Cu2O(111) surfaces could be used to obtain a deeper understanding of methanol dehydrogenation mechanisms with respect to adsorption sites on the surfaces. In this work, a detailed study was done of Cu2O(100) surface which revealed the possible surface structures as the result of different preparation conditions. Studies of the structure of Cu2O(100) and Cu2O(111) surfaces show that Cu2O(100) has a comparatively stable surface and reduces surface reactivity. As a consequence, dehydrogenation of methanol is more efficient on the Cu2O(111) surface. The hydrogen produced from methanol dehydrogenation is stored in oxygen adatom sites on both surfaces.QC 20161107
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Magni, M. "COPPER AND RUTHENIUM COMPLEXES IN SENSITIZED SOLAR CELLS AND OPTOELECTRONICS." Doctoral thesis, Università degli Studi di Milano, 2015. http://hdl.handle.net/2434/333099.
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In perfect harmony with the "Year of Light (IYL 2015)", the thesis has been entirely centered on the concept of Light involving the development of transition metal complexes for both the conversion of light into electric energy through dye-sensitized solar cells and, conversely, the production of light starting from electricity by fabrication of electroluminescent devices. The main part of the thesis has been devoted to the sunlight-to-electricity conversion, a target that is well contextualized within the global commitment for the progressive increase of the percentage of electric energy produced by renewable resources. In this context dye-sensitized solar cells, DSSCs, are promising devices alternative to the well established technology of silicon photovoltaics for energy production from the abundant solar light. DSSCs are devices able to harvest solar light and convert it into electricity employing a sensitizer (adsorbed on a semiconductor) and a redox couple properly chosen and combined. The project have concerned the design, synthesis and characterization of both sensitizers and redox mediators constituted by ruthenium and copper-based complexes respectively, together with their final assembly into laboratory-type DSSCs to evaluate their performance. In this way an all-round study has been carried out, from molecules on paper to test benches, passing through laboratory counters. The second, minor part, of the thesis has been focused on the diametrically opposed task, the generation of light. In this context some luminescent heteroleptic complexes based on the cheap and quite abundant copper element have been proposed. The final aim has been the synthesis of efficient luminophores for fabrication of devices able to generate light applying an electric potential across two electrodes such as in organic light-emitting diodes, OLEDs, or in analogue light-emitting electrochemical cells, LECs. The light production in LED-type devices is very efficient especially compared with other traditional artificial light sources like incandescent or fluorescent lamps, and so in line with the international policy of reducing energy consumption. In conclusion the thesis project can be schematically depicted as a circular pathway that joints together two opposite but strictly interconnected concepts (i.e. light and electricity) mutually corresponding to the task and the mean, the start and the end.
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Petersson, Jonas. "Ultrafast, Non-Equilibrium Electron Transfer Reactions of Molecular Complexes in Solution." Doctoral thesis, Uppsala universitet, Fysikalisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-235461.
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Photoinduced electron transfer is a fundamentally interesting process; it occurs everywhere in the natural world. Studies on electron transfer shed light on questions about the interaction between molecules and how the dynamics of these can be utilized to steer the electron transfer processes to achieve a desired goal. The goal may be to get electrons to the electrode of a solar cell, or to make the electrons form an energy rich fuel such as hydrogen, and it may also be an input or output for molecular switches. The importance of electron transfer reactions will be highlighted in this thesis, however, the main motivation is to gain a better understanding of the fundamental processes that affect the rate and direction of the electron transfer. A study of photoinduced electron transfer (ET) in a series of metallophorphyrin/bipyridinium complexes in aqueous solution provided fresh insight concerning the intimate relationship between vibrational relaxation and electron transfer. The forward electron transfer from porphyrin to bipyridinium as well as the following back electron transfer to the ground state could be observed by femtosecond transient absorption spectroscopy. Both the reactant and the product states of the ET processes were vibrationally unrelaxed, in contrary to what is assumed for most expressions of the ET rates. This could be understood from the observation of unrelaxed ground states. The excess energy given by the initial excitation of the porphyrin does not relax completely during the two steps of electron transfer. This is an unusual observation, not reported in the literature prior the studies presented in this thesis. This study also gave the first clear evidence of electronically excited radical pairs formed as products of intramolecular electron transfer. Signs of electronically excited radical pairs were seen in transient spectra, and were further verified by the observation that the rates followed a Marcus normal region behavior for all excitation wavelengths, despite the relatively large excess energy of the second excited state. This thesis also concerns electron transfer in solar cell dyes and mixed valence complexes. In the ruthenium polypyridyl complex Ru(dcb)2(NCS)2, where dcb = 4,4’-dicarboxy-2,2’-bipyridine, inter-ligand electron transfer (ILET) in the 3MLCT state was followed by means of femtosecond transient absorption anisotropy that was probed in the mid-IR region. Unexpectedly, ILET was not observed because electron density was localized on the same bpy during the time-window allowed by the rotational lifetime.
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Yeh, Ching-Hao, and 葉京澔. "The Experiment Course Design for Dye Sensitized Solar Cell (DSSC)." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/w77j37.
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碩士國立臺北科技大學
有機高分子研究所
102
Since photoelectric effect had been discovered in 19 century, the dream of using inexhaustible sun light as power generator had not been stopped. Scientists has improved the early stage inorganic metal solar cell to 3rd generation solar cell, such as organic flexible solar cell、quantum dot etc. So far, the 3rd generation solar cell seems no physical barrier like first two generation solar cell. Therefore, researchers in investigation of newer generation solar cell not only pursue the higher transfer efficiency in electricity, but also seeking more stability and economical material to reduce cost and expand popularity. Dye sensitized solar cell gains competitive advantages because of low cost、accessible manufacture processes and affordable equipment. After 1991 O’Regan and M.Gratzel published a solar cell with N3-dye reached 7-8% efficiency, in the past two decades, researchers had adjusted four major components, positive electrode、back electrode、electrolyte and dye in dye sensitized solar cell (DSSC). Due to different material selection and interface compatibility in DSSC is complicated, the change of one component and/or parameters would lead to the variation of photo current、voltage as well as solar cell efficiency. This kind of complexities results in thousands combination of batteries from different subtracts、electrolyte、dyes、fabrication method of working electrode to sealing skills, and it fascinate different field of scientists attempting different conjugation for better performance. Because of the various collocations, how to disassemble this complexity, I suggest choose from top down perspective. Starting from the measurement of cell efficiency to comprehend overall operation process, then tearing down into separated component to show how meliorated method to enhance performance, at the end , we sum up any possible factors. As a result, the experiment designation of this article follows principles mentioned above. At the beginning, we teach students how to measure the efficiency of solar cell, and understand parameter, such as FF, Isc, Voc ...etc. Through the definition of these parameters to reveal what the parameter is influenced by the variation of different components. For instance, one of the most important unit in dye sensitized solar cell is dye, but there are several factors could affect it. For example, different structure, complex metal dye with ruthenium in core、 dye with porphyrins and phthalocyanines or oraninc dye, they have different pros and cons. Take porphyrins and phthalocyanines as an instance, they may adopt D-π-A structure like organic dye and design different functional groups, not only lower the aggregation of sensitizer, but enhance the efficiency. In this thesis, we will sketch up a groups of experiment to show how different component may change and effect the efficiency. In the past two years learning journey in DSSC, I deeply endure its complexities and difficulties. In designation of DSSC, it is not only a challenge to consider compatibility of different components、complicated interface ,but also different background knowledge from semi-conductor、electrochemistry、surface chemistry …etc. In this thesis, I try to design a series of experiments across theory and practice based on factors influenced efficiency, and providing future researchers establish fundamental fabrication skills and background knowledge. I anticipate this series of experiments could be examples in the set-up of DSSC experimental courses.
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Chen, Chin-Hsing, and 陳進興. "Fabrication of Anodic Aluminum Oxide (AAO) for Dye-Sensitized Solar Cell (DSSC)." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/66537310518597249408.
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碩士國立交通大學
理學院碩士在職專班應用科技學程
97
In this study, we used commercial aluminum 1070 sheet (99.7% Aluminum) as the substrate. After anodization process, a high quality, uniform pore size, and regular anodic aluminum oxide template was produced. Moreover, the chemical deposition method was employed to hydrolyze and deposit titanium fluoride (TiF4) into the AAO template,to make titanium dioxide(TiO2) of dye sensitized solar cells was electron transfer layer,then the coaxial nanotube structure consisting of aluminum oxide and titanium oxide was obtained. On the other hand, immersing the nanotube in dye-sensitizer solution was the first process to obtain the anode of dye sensitized solar cell (DSSC).The fundamental sandwich structure of NT-DSSCs device composes of a cathode with sputter of transparent platinum catalyst, the anode with multiaxial type titanium dioxide/N3 dye and electrolyte (I-/I3-). The fabrication of AAO was formed by anodic oxidation of aluminum in different acid-based electrolytes, such as sulfuric acid, oxalic acid and phosphoric acid, which could synthesize the nanotube diameters of 18nm, 60nm and 200nm, respectively. By widening AAO pores, the template with uniform and regular pores, which were varied from 25nm to 500nm could be produced.
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Huang, Ching-Hui, and 黃清輝. "Structural Optimization for the Working Electrode of Dye-Sensitized Solar Cell (DSSC)." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/70052492614614420665.
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碩士國立交通大學
應用化學系所
96
Dye sensitized solar cell (DSSC) is one of the most promising photovoltaic devices due to its simple fabrication procedure, low cost, light weight, being semi-transparent and flexible, and it may be in different colors when different dyes and electrolytes are used. This dissertation demonstrates the principles, fabrication processes and I-V characteristics of DSSCs, which are related to the structure of the TiO2 layers prepared using spin-coating, doctor-blading and screen-printing methods. The topics of the dissertation include series resistance reduction, characterization the effect of an additional diffusion layer, and MgO-modified TiO2 layer. In addition, we developed a new screen-printing method to simplify and improve the fabrication procedure of the TiO2 layers. The experimental results show that the fill-factor and conversion efficiency of DSSCs were low when high series resistance were induced. The transparent TiO2 layer can be obtained by reducing the aggregation of the TiO2 paste. The conversion efficiency of DSSCs was improved when the light-harvesting was increased via a diffusion layer. In addition, the performance of a DSSC device can be enhanced when the TiO2 layer was treated with MgO, which gives the best photovoltaic performance of the device to be 6.8%.
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Lu, Hsueh-Pei, and 呂學沛. "Photovoltaic Investigations of Dye-Sensitized Solar Cell (DSSC) based on High-Performance Porphyrin Sensitizers." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/34524340637751483172.
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博士國立交通大學
應用化學系碩博士班
99
In this thesis, we the preparation of TiO2 pastes and photovoltaic measurement of DSSC devices. We tried to understand how the quality of the TiO2 pastes and the composites of the device affecting the device performance. The investigations were collaborated with Prof. Chen-Yu Yeh (NCHU). Novel porphyrin meso- or β- substituted porphyrins with a carboxyl group have been tested as sensitizers for DSSC. The results suggested that the photovoltaic properties of the DSSC can be affected by either the position of a bridge connecting the porphyrin ring and the number of carboxylic acid group. Because YD1 device showed the prominent performance the other porphyrin molecules were designed based on the structure of YD1. We investigated the effect of electron-donating group attached on a meso-position. The results show that the porphyrin with as alkyl-substituted diaryamino group (YD2), has higher stability and superior device performance. Then, we studied porphyrins with different types of bridges (YD11-13) for porphyrin-sensitized solar cell. The IPCE spectrum of YD12 has a Q-band shoulder slightly extended to longer wavelengths, resulting in a greater Jsc and higher power efficiency for YD12 than for YD11. In the last part, we studied the influence of electrolyte additives 4-t-butylpyridine (TBP) for porphyrin sensitized solar cell. We measured the device performance of YD12 and YD12CN with electrolytes containing different ratios of TBP. The additive TBP showed a significant influence on promoting the Voc of device. However, the effects of TBP additive on the device performance are different for YD12 and YD12CN. Electron-injection and charge-collection kinetics were reported to discuss the observed discrepancy.
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Huang, Chin-Hui, and 黃錦惠. "Photoelectric Characteristics and Impedance Analysis of Graphene Modified Arrayed Dye-sensitized Solar Cell." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/72323208307641785635.
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碩士國立雲林科技大學
電子工程系
103
In this thesis, the internal interface impedance of the dye-sensitized solar cell (DSSC) was investigated by the electrochemical impedance spectroscopy (EIS) with en equivalent circuit model in order to obtain the Nyquist plot, which simulated the effect of the electron transmission and the electron recombination on the photovoltaic properties of the dye-sensitized solar cell. And, the effects of surface morphology, crystal phase, film thickness, and photoelectric properties on the electron transfer mechanism and the photovoltaic parameters of the photoelectrode of the dye-sensitized solar cell were analyzed by scanning electron microscope (SEM), X-ray diffractometer (XRD), auger electron spectroscopy (AES), UV-visible spectroscopy (UV-vis) to improve the photoelectric conversion efficiency (η) of the dye-sensitized solar cell. The effect of graphene content, annealing temperature of titanium dioxide (TiO2)/graphene composite film, series-parallel connection modules, and the structure of the photoelectrode on dye-sensitized solar cell were analyzed. According to the results, the short circuit current density (Jsc) and η were promoted with increasing the graphene content. The Jsc was enhanced when the TiO2/Graphene composite film was annealed at 450 ℃ to 550 ℃. The impedance was deceased with increasing the parallel connection modules. However, the series modules were increased, which led to increasing impedance.
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Chang, Ken-Hao, and 張根豪. "Theoretical Study for Thienoisoindigo（TII） Derivatives on D-A1-π-A2 Type Dye-sensitized Solar Cell（DSSC）." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/u65rb7.
Full textAbstract:
碩士淡江大學
化學學系碩士班
104
In this paper, we studies donor effect and acceptor effect for Thienoisoindigo (TII) derivatives at D-A1-π-A2 types Dye-sensitized Solar Cell (DSSC). We discuss dyes optimization structure by B3LYP/ 6-31G（d）method. The electronic properties was calculated by CAM-B3LYP/ 6-31G（d）method. The optical properties was calculated by TD/BHandHLYP/6-31G（d）method. First, we link eight different electron-donor (D) to same -TII-T-CA moiety to discuss donor effect. Acroding to the reasult, the electron-donor (D) has stronger doating ability and high planer between D and TII will cause the HOMO energy increase, the ΔGinj. increase, the maximum absorption wavelength red shift, u_normal increase. In this discussion, We chose DPA fragments to be a good electron-donor (D). Than, we link nine different electron-acceptor(A2) to same DPA-TII-T- moiety to discuss acceptor effect. Acroding to the reasult, the electron-acceptor (A2) has stronger withdrawing ability will cause the LUMO energy decrease, the ΔGinj. increase, the maximum absorption wavelength red shift, u_normal increase. RLHE increase, life-time decrease, leading dyes to be ICT performance. The ECTE needs to consider not only withdrawing ability of electron-acceptor (A2) but also the planarity between anchoring group (COOH) and electron-acceptor (A2). We chose CA fragments to be a good electron-acceptor (A2) in this part. Finily, combining with donor effect and acceptor effect, we choose DPA-TII-T-CA to be a good candidate in this paper. And giving a role to select a good candidate for D-A1-π-A2 type Dye-sensitized Solar Cell（DSSC）.
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Sharmila, S. "Studies On Fabrication And Characterisation Of TiO2 Based Dye-Sensitised Solar Cells." Thesis, 2015. http://etd.iisc.ernet.in/handle/2005/2639.
Full textAbstract:
Photovoltaic cells are a promising solution to the current energy crisis. Among the different photovoltaic cell technologies developed, dye-sensitised solar cells (DSSC) are emerging as viable low-cost alternatives to Si PV technology. This thesis presents studies on fabrication and characterisation of TiO2 based dye-sensitised solar cells. Chapter 1 gives an overview of different photovoltaic cell technologies and a review of the state-of-the art DSSC technology. Chapter 2 describes the techniques used for characterisation of DSSCs. Chapter 3 describes the fabrication of TiO2 based dye-sensitised solar cells. Chapter 4 presents the analysis of measurements obtained by the characterisation techniques. Finally chapter 5 summarises the work done and suggests directions for future work.
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Mbonyiryivuze, Agnes. "Indigenous natural dyes for Gratzel solar cells : Sepia melanin." Diss., 2014. http://hdl.handle.net/10500/19034.
Full textAbstract:
Dye-sensitized Solar Cells (DSSC), also known as Grätzel cells, have been identified as a cost-effective, easy-to-manufacture alternative to conventional solar cells. While mimicking natural photosynthesis, they are currently the most efficient third-generation solar technology available. Among others, their cost is dominated by the synthetic dye which consists of efficient Ruthenium based complexes due to their high and wide spectral absorbance. However, the severe toxicity, sophisticated preparation techniques as well as the elevated total cost of the sensitizing dye is of concern.
Consequently, the current global trend in the field focuses on the exploitation of alternative organic dyes such as natural dyes which have been studied intensively. The main attractive features of natural dyes are their availability, environmental friendly, less toxicity, less polluting and low in cost. This contribution reports on the possibility of using sepia melanin dye for such DSSC application in replacement of standard costly ruthenium dyes.
The sepia melanin polymer has interesting properties such as a considerable spectral absorbance width due to the high degree of conjugation of the molecule. This polymer is capable of absorbing light quantum, both at low and high energies ranging from the infrared to the UV region.
The comprehensive literature survey on Grätzel solar cells, its operating principle, as well as its sensitization by natural dyes focusing on sepia melanin has been provided in this master’s dissertation. The obtained results in investigating the morphology, chemical composition, crystalline structure as well as optical properties of sepia melanin samples using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy x-ray diffraction, X-ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Raman spectroscopy, UV-VIS absorption spectroscopy as well as Photoluminescence (PL) for Grätzel solar cell application have been reported.
These results represent an important step forward in defining the structure of melanin. The results clearly show that sepia melanin can be used as natural dye to DSSC sensitization. It is promising for the realization of high cell performance, low-cost production, and non-toxicity. It should be emphasized here that natural dyes from food are better for human health than synthetic dyes.Physics
1 online resource (xii, 101 leaves) : illustrations
M. Sc. (Physics)
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Shun-An, Yang, and 楊順安. "The effects of Pt/In/ITO and Pt/Sn/ITO electrodes on the electrochemical impedance characteristics of Dye-sensitized solar cell." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/01972645788245680641.
Full textAbstract:
碩士南台科技大學
光電工程系
97
In order to search for an efficient and low cost counter electrode in a DSSC, In and Sn nanoparticles were grown onto ITO substrates, on which a thin Pt layer was coated. This sandwich structure was used to explore the performance of the counter electrode in DSSC. The effects of the morphology, average roughness and charge-transfer resistance of surface modified Pt counter electrode on the performance of a DSSC were investigated. The Pt counter electrode with In or Sn under layer was prepared by E-gun evaporation method. The surface morphology and structure of Pt films were examined by Scanning Electron Microscope (SEM). The sheet resistance was examined by four-point probe. The roughness factor was examined by Atomic Force Microscopy (AFM). The charge-transfer resistance was examined by autolab potentiostat. The result shows that surface roughness (Ra) is increased by the increase of film thickness, but the charge-transfer resistance (Rct) is not improved with the increase of Ra . Nevertheless, as the thickness of Pt and underlay was approximately 1:1, the Rct performed better behavior than simple Pt coated ITO. Comparing Sn and In, In underlay shows better performance because the melting point of In is lower, which leads the substrate could be fully covered by Pt. Pt/Sn(In)/ITO counter electrodes have a good chemical stability to I3-/I- couple. The lowest charge transfer impedance of approximately 1.63Ωcm2 can be obtained for an electrode area of 0.196cm2 (Pt (2nm)/In(3nm)/ITO1) electrode. The conversion efficiency is estimated to be 5.42%. However, the best conversion efficiency 5.7% can be obtained on the annealed In (2nm) underlay. On PET substrate, the presence of In underlay not only improves the adhesion of Pt on PET, but also raises the conversion efficiency from 3.84% to 6.08%.
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KO, CHENG-CHU, and 柯承初. "Investigation of Photovoltaic Properties and Equivalent Circuit Impedance Analysis for Dye-sensitized Solar Cell Based on AZO Photoanode and Pt Counter Electrode Modified by Reduced Graphene Oxide under Low Illumination, and Study in Series-Parallel Connection Modules." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/86nyah.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
107
In this thesis, the dye-sensitized solar cells (DSSCs) were fabricated on fluorine doped tin oxide (FTO) glass or flexible indium tin oxide/ polyethylene terephthalate (ITO/PET). The photoanode was double layer structure. Firstly, we deposited the Al-doped zinc oxide (AZO) seed layer on FTO glass by sputter system and then grew the zinc oxide (ZnO) nanorods on the AZO seed layer by hydrothermal method. Finally, we deposited the titanium dioxide (TiO2) on ZnO nanorods by the doctor blade method, the photoanode had been finished. The ZnO nanorods could increase the dye adsorption. In the other part, the platinum (Pt) modified is by reduced graphene oxide (rGO). The rGO is two-dimensional materials, which has a high surface and area-to-volume ratio. The rGO was deposited on platinum counter electrode by the doctor-blade method and it can enhance the electrocatalytic activity of the counter electrode. Finally, we measured the current density-voltage curves of the dye-sensitized solar cell (DSSCs), used electrochemical impedance spectroscopy (EIS) to measure impedance and used field emission scanning electron microscopy (FE-SEM) to observe surface morphology of the DSSCs. This new structure could make dye absorbed in a photoanode increase. We know the current situation by ultraviolet-visible spectroscopy. Consequently, This produced an increase in the photoanode ability to absorb the dye, which in turn increased the cell’s short circuit current density, raising the photovoltaic conversion efficiency from 3.71% to 4.87%. In addition, we made the DSSCs module which connected 2 devices in series and 2 devices in parallel and performed the stability analysis. In addition, The DSSCs was measured under the different light intensities. Corresponding to the results, when the light intensity was reduced from 100 mW/cm2 to 30 mW/cm2, the fill factor and the photovoltaic conversion efficiency were increased from 52.85 % to 63.45 % and 4.01 % to 5.25 %, respectively. The photovoltaic conversion efficiency was grown up to 7.82 % when the DSSCs were operated under T5 fluorescent light which light intensities were 0.2 mW/cm2 - 1.7 mW/cm2.
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Kuo, Chien-Hung, and 郭建宏. "Investigation on Photovoltaic Properties of Flexible Arrayed Dye-sensitized Solar Cell Based on IGZO/ TiO2 Double Layered Structure Modified by Graphene under the Low Illumination and Study on Impedance Analysis and Wireless-based Remote Real-time Monitoring System." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/a6xv27.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
106
In this thesis, a way to improve the photovoltaic conversion efficiency (η) of dye-sensitized solar cell (DSSC) has been provided. The structure was divided into two parts. In the first part, the reduced graphene oxide (RGO) - TiO2 composite was fabricated by using hydro-thermal method, which was acted as the dye - adsorbed layer. In the second part, the indium gallium zinc oxide (IGZO) was deposited between dye-adsorbed layer and electrolyte by using sputter system. The DSSC was investigated by electrochemical impedance spectroscopy (EIS), sun light simulation system, field emission scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), ultraviolet-visible spectrophotometer (UV-Visible), X-ray photoelectron spectroscopy (XPS)/electron spectroscopy for chemical analysis (ESCA), X-ray diffractometer (XRD), Raman spectroscopy and transmission electron microscope (TEM). We investigated the photovoltaic properties, series-parallel connection module, internal interface impedance, surface morphology and energy band diagram of arrayed dye-sensitized solar cell based on RGO - TiO2 /IGZO photoelectrode under low illumination. According to the experimental results, due to the high mobility of RGO, which acted as a bridge and accelerated the electron transportation from conduction band of titanium dioxide to conduction band of fluorine doped tin oxide (FTO) glass. That was to say, probability of electron recombination between photo-generated electrons and oxidized-dye molecule was reduced. Furthermore, the energy band gap of dye-adsorbed layer decreased after introducing RGO, which could extend the wavelength range of absorbed-light. Particularly, the amount of harvesting-light is increased. In addition, the high specific surface of RGO was able to increase the amount of dye-loading. The IGZO film was acted as an energy barrier to prevent I-3 from recombining with electrons, which means that it could reduce the probability of reverse recombination. Those modifications of photoelectrode could improve the short-circuit current density (Jsc) of DSSC. Because the photo-generated electrons were reduced with decrease in illumination intensity, that indicated the scattering among electrons was reduced. In order words, the photoluminescence quantum yield (PLQY) will be increased, and the photovoltaic conversion efficiency of DSSC could increase under lower illumination intensity. Finally, the device was investigated by using the wireless-based remote real-time monitor, stability and life-time by source measure unit (SMU) and LabVIEW from National Instruments.
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YOU, PEI-HONG, and 游培弘. "Investigation on the Photovoltaic Characteristics of Flexible Arrayed TiO2 Dye-sensitized Solar Cell Modified by Graphene and Magnetic Beads Integrated with ZnO Nanowires under the Low Illumination and Study on Impedance Analysis of Large-area Series-parallel Equivalent Circuit." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/xc2mb5.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
105
In this thesis, we focused on the performance improvement of dye-sensitized solar cell (DSSC). First, the zinc oxide nanowires was deposited on the different substrates by using water bath method, such as fluorine-doped tin oxide/glass (FTO/Glass) substrate and the indium tin oxide/polyethylene terephthalate (ITO/PET) substrate. After that, the different contents of graphene oxide (GO) and magnetic beads (MBs) were incorporated into titanium dioxide, which will be deposited on the zinc oxide nanowires film by using spin coating method. The optimal incorporating ratio of GO-MBs-TiO2/ zinc oxide nanowires is investigated for the photoelectrode. On the other hand, we also analyzed the series-parallel connection modules and the effects of low illumination for the photovoltaic properties of DSSC. For optimal device, the surface morphology, film thickness, crystalline phase, the optical and photoelectric properties of composite film will be investigated by scanning electron microscope (SEM), X-ray diffractometer (XRD), UV-visible spectroscopy (UV-vis) and electrochemical impedance spectroscopy (EIS). According to the experimental results, the content of 1.5 mL GO and 0.5 mL MBs for DSSC had the optimal photovoltaic properties performances. The optimal photovoltaic conversion efficiency (η) was 4.46 %. Finally, the DSSC of optimal composite film was investigated under different light intensities, which achieved the higher η of 5.21 % a 10 mW/cm2 illumination. The impedance decreased/increased with the increasing connections of the parallel/series module, which photovoltaic conversion efficiencies were 2.81 % and 4.21%, respectively. When use the large area module (2 series + 2 parallel), which η was 3.02%. The optimal η was 3.93% under 10 mW/cm2 illumination.
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Bartoň, Jan. "Nové přístupy k chemické modifikaci diamantových povrchů." Doctoral thesis, 2020. http://www.nusl.cz/ntk/nusl-435163.
Full textAbstract:
1 Abstract Diamond is a unique material for its physical and chemical stability. However, many advance applications rely on surface functionalisation. Here, two types of diamond were modified on the surface - thin layer of chemical vapor deposition (CVD) and nanodiamond particles (NDs) high pressure and high temperature (HPHT). The aim of CVD surface modification was to prepare photosensitised, conductive, diamond electrodes for dye sensitized solar cells (DSSC). For this purpose, a thin diamond layer doped with boron was deposited on the silicon wafer. Boron doping provided p-type (semi)conductivity to diamonds. The surface of the diamond was hydrogenated with H-plasma, and a short carbon linker with a protected amino group was UV-photografted to the surface. In another study, a photoconverting dye (P1) was covalently attached to the amine-linker. Furthermore, a dye designed based on donor-π-acceptor (D-π-A) concepts was attached to the surface. Finally, a systematic study was done for differently conductive diamond layer and the underlying silicon wafer These experiments gradually lead to the highest ever reported photocurrents of 6.6 µA cm2 for a flat photosensitised boron-doped-diamond (BDD) electrode. Monomolecular layer surface functionalizations on CVD diamond are difficult to detect or even quantify...