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1
Andersson, Lars Mattias. "Electronic Transport in Polymeric Solar Cells and Transistors." Doctoral thesis, Linköping : Department of Physics, Chemistry and Biology, Linköping University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10380.
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Mbambisa, Gcineka. "Polymeric-bimetallic oxide nanoalloy for the construction of photovoltaic cells." University of the Western Cape, 2014. http://hdl.handle.net/11394/4364.
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Philosophiae Doctor - PhDResearch in renewable energy has become a focal point as a solution to the energy crisis. One of renewable forms of energy is solar energy, with the main challenge in the development of the solar cells being the high cost. This has led to the exploration of the use of organic molecules to construct solar cells since it will lead to lowered costs of construction. The focus of this research is on the synthesis and characterisation of the polyaniline derivatives materials and zinc gallate for application in the construction of hybrid solar cells with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as an acceptor. The polyaniline (PANi) and doped polyaniline derivatives, polyaniline phenathrene sulfonic acid (PANi-PSA), poly[ortho-methyl aniline] phenanthrene sulfonc acid (POMA-PSA) poly[ortho-methyl aniline] anthracene sulfonc acid (POMA-ASA) were produced via chemical synthetic procedures. The zinc gallate (ZnGa2O4) was also produced using a chemical method. The vibrational and electronic spectra of the polymers and zinc gallate were interrogated independently and dependently. Electronic transitions due to charge defects (polarons and bipolarons) were observed for the polymers that are doped. The PANi was the one with the lowest band gap of 2.4 eV with the POMA-ASA having the widest bandgap of 3.0 eV. The XRD and TEM analysis of the polymers revealed characteristics that show that the PANi has the highest level of crystallinity and the POMA-ASA displayed the least level of crystallinity. The electronic data, XRD, TEM data led to the conclusion that the conductivity of the polymers is decreasing in the following sequence, PANi > PANi-PSA > POMA-PSA > POMA-ASA. The photoluminescence of the polymers alone and with the nanoparticles was investigated in solution and on an ITO coated glass substrate. Photoluminescence was observed for the polymers due to relaxation of the exciton and also from the formation of excimers. The relaxation due to the exciton was observed at higher energy levels, while the one that is as a result of the excimer formation was seen at lower energy levels. Enhancement of the peak due to the excimer was observed when the compound is mixed with the nanoparticles in solution. When the analysis was done on the ITO coated glass substrate, it was found that zinc gallate does not lead to quenching of the emission of the polymers; hence it can not be used as an acceptor in this particular system. The electrochemical behaviour of the polyaniline derivatives was investigated using cyclic voltammetry and electrochemical impedance spectroscopy. Interaction of the polymers with the PCBM (acceptor) was investigated using UV-visible absorption spectroscopy and photoluminescence spectroscopy. It was able to quench the photoluminescence of the polymers. Hence it was used as an acceptor in the construction of the photovoltaic cells. The polymers alone and with the nanoparticles were used in the formation of bulk heterojunction photovoltaic cells with PCBM as an acceptor. The photovoltaic behaviour was investigated and PANi was the one that displayed the highest efficiency.
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Ripollés, Sanchis Teresa. "Interfacial and Bulk Operation of Polymeric Solar Cells by Optoelectronics and Structural Techniques." Doctoral thesis, Universitat Jaume I, 2014. http://hdl.handle.net/10803/277095.
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This Ph.D. Thesis focuses on the investigation of organic photovoltaic (OPV) technology, especially in aspects of experimental device processing, and optoelectronic and electrical characterization on OPV devices to be readily marketable. More specifically, the topics addressed are the following: origin of recombination current,open-circuit voltage and crystallinity, transport driving force, contact selectivity and interface states, alternative hole transporting layers and oxygen and degradation routes.
4
Mangold, Hannah [Verfasser]. "Charge separation and recombination in novel polymeric absorber materials for organic solar cells : a photophysical study / Hannah Mangold." Mainz : Universitätsbibliothek Mainz, 2013. http://d-nb.info/1046208454/34.
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Ekhagen, Sebastian. "Stability of electron acceptor materials for organic solar cells : a work function study of C60/C70 derivatives and N2200." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-72727.
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Thin films of the fullerenes PC60BM and PC70BM and the non-fullerene N2200, three popular electron acceptor materials in organic photovoltaics, have been studied, using both the Kelvin probe method as well as ultraviolet photoelectron spectroscopy. With these methods the work function was measured, as well as the highest occupied molecular orbital (HOMO) onset. Additionally band bending effects were studied by illuminating the samples while measuring the work function with the Kelvin probe so called surface photovoltage. Sample of each material was exposed to either air and simulated sunlight or N2 and simulated sunlight, for different length of time, to observe how the materials work function evolves after exposure to the different conditions. It was observed that, as expected from previous studies, that PC60BM was less photo-stable than PC70BM. Additionally, the work function of PC60BM changed significantly by storage in N2. Each material after exposure for 24h to air and light, was annealed and measured with the Kelvin probe. A restoring effect was observed, for the non-fullerene material N2200. All three materials developed an increasing surface photovoltage, which suggest increased band bending, when exposed to air and light, indicating that due phot-oxidization, charges are redistributed at the surface of the film. The fullerenes showed a larger surface photovoltage effect than the non-fullerene materials. A difference between the work function values obtained from the Kelvin probe method and the ultraviolet photoelectron spectroscopy could be seen, however the exact reason for this couldn't be isolated within this thesis, but was discussed.
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Quadretti, Debora. "Nuovi polimeri tiofenici per celle fotovoltaiche con architettura BHJ." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16662/.
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Recently, as the fossil fuels strongly decreased, several studies have been conducted in order to exploit solar power as an alternative source of energy. To make this possible with sustainable costs, the attention has been focused on the development of organic photovoltaic solar cells (OPVs) based on polymeric photoactive layer. The aim of this work is to describe the synthesis and characterization of new copolymers, poly[3-(6-fullerenylhexyl)thiophene-co-3-(6-bromohexyl)thiophene], starting from soluble regioregular (PT6BrR) and regiorandom (PT6Br) homopolymeric precursors. These materials are new intrinsically conductive copolymers made of thiophenic units bearing a fullerene and a bromine atom at the end of a hexylic side chain. The obtained homopolymers and copolymers have been widely characterized with different techniques, such as 1H-NMR, FT-IR and UV-Vis spectroscopy, thermal analysis (DSC and TGA) and gel permeation chromatography (GPC). All the synthesized materials were tested as active media in organic solar devices of BHJ type, blended with PC61BM (1:1 w/w) as the acceptor material and as double-cable materials.
7
Liu, Hua. "Investigation on Transport Mechanisms and Interfacial Properties of Solar Cells By Simulation." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1365873270.
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Braun, Slawomir. "Studies of Materials and Interfaces for Organic Electronics." Doctoral thesis, Linköping : Univ, 2007. http://www.bibl.liu.se/liupubl/disp/disp2007/tek1103s.pdf.
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Yi, Chao. "Towards High Performance Polymer Solar Cells Through Interface Engineering." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1367597024.
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He, Yinghui. "Novel N-type Π-conjugated Polymers for all-polymer solar cells." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0651/document.
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Les cellules solaires organiques (OSC) apparaissent comme une technologie prometteuse pour les énergies renouvelables en raison de leur poids léger, leur grande flexibilité et leur processus de fabrication peu coûteux. Jusqu'à présent, la plupart des OPV ont utilisé des dérivés de Fullerene, tels que PCBM ou PC71BM, en tant qu'accepteur d'électrons dans la couche active, qui s'est avéré être un goulet d'étranglement pour cette technologie. Par conséquent, le développement d'accepteurs non-fullerene est devenu la nouvelle force motrice de ce domaine. Les cellules solaires tout-polymères (tous-PSC) qui ont les avantages de la robustesse, de la stabilité et de l'accessibilité ont déjà atteint PCE jusqu'à 9%. Ainsi, le développement de nouveaux matériaux accepteurs est impératif pour améliorer les performances de tous les PSCOrganic solar cells (OSCs) appear as a promising technology for renewable energy owing to their light weight, great flexibility and low-cost fabrication process. So far most of the OPV shave been using fullerene derivatives, such as PCBM or PC71BM, as the electron acceptor in the active layer, which have been proven to a bottleneck for this technology. Therefore,developing non-fullerene acceptors has become the new driving force for this field. All-polymer solar cells (all-PSCs) that have the advantages of robustness, stability and tunability have already achieved PCE up to 9%. Thus, developing novel acceptor materials is imperative for improving the performance of all-PSCs
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Hadipour, Afshin. "Polymer tandem solar cells." [S.l. : Groningen : s.n. ; University Library of Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/305349066.
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Gowrishankar, Vignesh. "Nanostructured inorganic / polymer solar cells /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Han, Lu. "Synthesis of a Fullerene Acceptor with Visible Absorption for Polymer Solar Cells." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1399248320.
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Mori, Daisuke. "Development of Polymer Blend Solar Cells Composed of Conjugated Donor and Acceptor Polymers." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199331.
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Yamamoto, Shunsuke. "Charge Carrier Dynamics in Polymer Solar Cells." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157616.
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Dittmer, Janke Jörn. "Dye/polymer blends for organic solar cells." Thesis, University of Cambridge, 2001. https://www.repository.cam.ac.uk/handle/1810/251783.
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Saif, Addin Burhan K. (Burhan Khalid). "The challenges of organic polymer solar cells." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/62740.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 108-110).
The technical and commercial prospects of polymer solar cells were evaluated. Polymer solar cells are an attractive approach to fabricate and deploy roll-to-roll processed solar cells that are reasonably efficient (total PV system efficiency>10%), scalable and inexpensive to make and install (<100 $/m2). At a cost of less than 1$/Wp, PV systems will be able to generate electricity in most geographical locations at costs competitive to coal's electricity (at 5-6 cents/KWh) and will make electricity available to more people around the world (-20% of the world population is without electricity). In this chapter, we explore organic polymer solar cell technology. The first chapter discusses the potential impact of solar cells on electricity markets and the developing world and its promise as a sustainable scalable low carbon energy technology. The second chapter discusses some of the complexity in designing polymer solar cells from new materials and the physics involved in some detail. I also discuss the need to develop new solution processed transparent conductors, cost effective encapsulation and long life flexible substrates. The third chapter discusses polymer solar cells cost estimates and how innovative designs for new modules could reduce installation costs. In the final chapter I discussed the prospects for commercialization of polymer solar cells in several niche markets and in grid electricity markets; the commiseration prospects are dim especially with the uncertainty in the potential improvement in polymer solar cell stability.
by Burhan K. Saif Addin.
M.Eng.
18
Yu, Fei. "Graphene-enhanced Polymer Bulk-heterojunction Solar Cells." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1439310775.
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Nagata, Shinobu. "ELECTROSPUN POLYMER-FIBER SOLAR CELL." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/2566.
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A study of fabricating the first electrospun polymer-fiber solar cell with MEHPPV is presented. Motivation for the work and a brief history of solar cell is given. Limiting factors to improvement of polymer solar cell efficiency are illustrated. Electrospinning is introduced as a technique that may increase polymer solar cell efficiency, and a list of advantages in the technique applied to solar cell is discussed. Results of electrospun polymer-fiber solar cell, absorption, and its device parameter diagnosis through an equivalent circuit analysis are presented.
20
Cheung, Kai-yin, and 張啓賢. "Metallopolyyne polymers based bulk heterojunction (BHJ) solar cells." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841719.
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Cheung, Kai-yin. "Metallopolyyne polymers based bulk heterojunction (BHJ) solar cells." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841719.
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WU, DEZHEN. "Magnetic Field Effects Induced by Incorporation of Magnetic Nanoparticles on Bulk Heterojunction Polymer Solar Cells." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1525107259345629.
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Xu, Huajun. "Near-IR Dye Sensitization of Polymer Solar Cells." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188604.
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Wang, Yanbin. "Exciton Harvesting in Ternary Blend Polymer Solar Cells." 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/192193.
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Shambayati, Shabnam. "Degradation of P3HT:PCBM-based conjugated polymer solar cells." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36888.
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This work examines the effect of regioregularity (RR) and zinc oxide (ZnO) nanoparticle doping on the degradation of poly(3-hexylthiophene) (P3HT):6,6-phenyl C₆₁-butyric acid methyl ester (PCBM) organic solar cells. This is done through application of semi-compact models that relate experimentally measured transport characteristics to structural properties. In this way, the contribution of regioregularity and ZnO nanoparticles to the change in structural
properties can be quantified. These models allow interpretation of experimental data and insight into the underlying degradation mechanisms. In this thesis, the mobility edge model is used, and corresponding parameters such as effective electron and hole mobilities are extracted and compared. These results show that studying electron transport plays a critical role in
understanding the degradation of P3HT:PCBM solar cells.
Examination of regioregular devices reveals that the drop in effective electron mobility with annealing for the high RR devices is greater than that of the low RR ones. This is attributed to the greater tendency for crystallization-driven phase segregation in blends of 98% RR P3HT and PCBM. In hybrid polymer-ZnO devices, effective electron mobility improves with the addition of an optimal concentration of ZnO. The decline in electron
effective mobilities with annealing is smaller for the devices containing ZnO in comparison to devices without ZnO. Studying the morphology of these devices shows that the phase segregation is identical for devices with and without ZnO.
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Maurano, Andrea. "Charge Carrier Losses in Polymer/Fullerene Solar Cells." Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525151.
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Sun, Yechuan, and 孙也川. "Improvement of polymer solar cells through device design." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B47849940.
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In this thesis, fabrication of polymer solar cells through different device designs is presented and the resulted solar cell performance is discussed. Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) are chosen as the photoactive layer materials as this material combination has been widely used and well investigated. The known properties of P3HT and PCBM make systematical studies and modeling for the effect of device designs on the performance of polymer solar cells possible although this is beyond the scope of this thesis.
First, ITO electrodes were fabricated by sputtering and used as the transparent electrode for polymer solar cells. Properties of ITO film fabricated by different sputtering conditions were compared. Radio frequency (RF) sputtered ITO was found to exhibit the best transparency overall. This condition was further applied to the fabrication of ITO electrode for polymer solar cells with light trapping structures. Low temperature processed silicon oxide (SiOx) / titanium oxide (TiOx) periodic structures were fabricated by sol-gel method. Optical transmittance of the bottom electrode was altered by the presence of the reflective coating and thus the absorption in the photoactive layer was affected. By varying the number of layer pairs and thickness of each layer in the reflective coating, improvement of polymer solar cell performance was found by inserting reflective coating for optimized conditions. Finally, semi-transparent polymer solar cells with inverted structure were demonstrated using conductive polymer as the anode. The process in device preparation was vacuum-free and thus could be potentially useful in large-scale roll-to-roll fabrication.published_or_final_version
Physics
Master
Master of Philosophy
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Alqurashi, Rania. "Interface electronic structure of inverted polymer solar cells." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/19062/.
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Brenner, Thomas Johannes Konrad. "Device physics of bulk heterojunction polymer solar cells." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610312.
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Hansson, Rickard. "Morphology and material stability in polymer solar cells." Licentiate thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-37843.
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Polymer solar cells are promising in that they are inexpensive to produce, and due to their mechanical flexibility have the potential for use in applications not possible for more traditional types of solar cells. The performance of polymer solar cells depends strongly on the distribution of electron donor and acceptor material in the active layer. Understanding the connection between morphology and performance as well as how to control the morphology, is therefore of great importance. Furthermore, improving the lifetime of polymer solar cells has become at least as important as improving the efficiency. In this thesis, the relation between morphology and solar cell performance is studied, and the material stability for blend films of the thiophene-quinoxaline copolymer TQ1 and the fullerene derivatives PCBM and PC70BM. Atomic force microscopy (AFM) and scanning transmission X-ray microscopy (STXM) are used to investigate the lateral morphology, secondary ion mass spectrometry (SIMS) to measure the vertical morphology and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy to determine the surface composition. Lateral phase-separated domains are observed whose size is correlated to the solar cell performance, while the observed TQ1 surface enrichment does not affect the performance. Changes to the unoccupied molecular orbitals as a result of illumination in ambient air are observed by NEXAFS spectroscopy for PCBM, but not for TQ1. The NEXAFS spectrum of PCBM in a blend with TQ1 changes more than that of pristine PCBM. Solar cells in which the active layer has been illuminated in air prior to the deposition of the top electrode exhibit greatly reduced electrical performance. The valence band and absorption spectrum of TQ1 is affected by illumination in air, but the effects are not large enough to account for losses in solar cell performance, which are mainly attributed to PCBM degradation at the active layer surface.The performance of polymer solar cells depends strongly on the distribution of electron donor and acceptor material in the active layer. Understanding the connection between morphology and performance as well as how to control the morphology, is therefore of great importance. Furthermore, improving the lifetime has become at least as important as improving the efficiency for polymer solar cells to become a viable technology. In this work, the relation between morphology and solar cell performance is studied as well as the material stability for polymer:fullerene blend films. A combination of microscopic and spectroscopic methods is used to investigate the lateral and vertical morphology as well as the surface composition. Lateral phase-separated domains are observed whose size is correlated to the solar cell performance, while the observed surface enrichment of polymer does not affect the performance. Changes to the unoccupied molecular states as a result of illumination in ambient air are observed for the fullerene, but not for the polymer, and fullerenes in a blend change more than pristine fullerenes. Solar cells in which the active layer has been illuminated exhibit greatly reduced electrical performance, mainly attributed to fullerene degradation at the active layer surface.
Paper 2 ingick som manuskript i avhandlingen. Nu publicerad.
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Sweet, Marshall. "Water Soluble Polymer Solar Cells from Electrospray Deposition." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3161.
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This dissertation reports the fabrication and characterization of thin films from the water soluble polymer sodium poly[2-(3-thienyl)-ethyloxy-4-butylsulfonate] (PTEBS) by electrospray deposition (ESD). Contiguous thin films were created by adjusting the parameters of the electrospray apparatus and solution properties to maintain a steady Taylor cone for uniform nanoparticle aerosolization and controlling the particle water content to enable coalescence with previously deposited particles. The majority of deposited particles had diameters less than 52 nm. A thin film of 64.7 nm with a root mean square surface roughness of 20.2 nm was achieved after 40 minutes of ESD. Hybrid Solar Cells (HSCs) with PTEBS thin films from spin coating and electrospray deposition (ESD) were fabricated, tested, and modeled. A single device structure of FTO/TiO2/PTEBS/Au was used to study the effects of ESD of the PTEBS layer on device performance. ESD was found to double the short circuit current density (Jsc) by a factor of 2 while decreasing the open circuit voltage (Voc) by half compared to spin coated PTEBS films. Comparable efficiencies of 0.009% were achieved from both device construction types. Current-Voltage curves were modeled using the characteristic solar cell equation showed a similar increase in generated photocurrent with a decrease of two orders of magnitude in the saturation current in devices from ESD films. Increases in Jsc are attributed to increased interfacial contact area between the TiO2 and PTEBS layers, while decreases in Voc are from poor film quality from ESD. Polymer solar cells (PSCs) with water-soluble active layers deposited by ESD were fabricated and tested. The water soluble, bulk heterojunction active layers consisted of PTEBS and the fullerene C60 pyrrolidine tris-acid. A single device structure of ITO/PEDOT:PSS/bulk(PTEBS+C60)/Al was used to study the effect of PTEBS to C60 tris-acid ratio on photovoltaic performance. An active layer ratio of PTEBS:C60 tris-acid (1:2) achieved the highest power conversion efficiency (0.0022%), fill factor (0.25), and open circuit voltage (0.56 V). The percolation threshold of C60 was achieved between 1 part PTEBS and 2 to 3 parts C60. Increasing the C60 tris-acid ratio (1:3) improved short circuit current, but reduced the open circuit voltage enough to lower efficiency.
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LA, NOTTE LUCA. "Scale-up of bulk-heterojunction polymer solar cells." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2013. http://hdl.handle.net/2108/203233.
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Polymer solar cells (PSCs) have recently reported a marked improvement in conversion efficiency, exceeding 10%, thus reducing the gap with more mature photovoltaic technologies. Now the transfer of such performances to the large scale has to be carried out by using industrially relevant techniques such as spray and slot die coating, and inkjet, gravure, flexographic and screen printing. This work is focused on the scale up of the PSCs by exploiting spray coating, a simple and low cost method already successfully applied to PSC layers. Firstly in literature a fully sprayed module was fabricated on glass substrate by an automated machine in air. Moreover, modules comprising a sprayed active layer were realized on flexible substrates. Both of them yielded ~1% of efficiency and supplied small power electronic devices. The aim to increase the efficiency of the modules addressed the activity towards two aspects. The first one concerned the investigation of new sprayable materials, i.e. low-temperature TiOX and PFN as interlayers and PBDTTT-C-T:PC71BM as active layer, all processed in safe solvents. The second one regarded the influence of the patterning methods, such as mechanical scribing and additive patterning through aerosol jet pre-printing, on the electrical parameters of the device. Finally, a lot of attention was focused on the stability issue. Encapsulation with commercial polymers was employed by heat sealing and this method revealed to be effective in the assembly of a fully solution-processed panel for greenhouse applications. Furthermore, the intrinsic stability of the device structure was analyzed; it was demonstrated that the electron transport layer and the solvent in which it is dissolved have a great influence on the device stability.
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ZAMPETTI, ANDREA. "Heterostructures and interfacial layers for polymer solar cells." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2013. http://hdl.handle.net/2108/203509.
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This thesis is concerned with the study and the development of bulk heterostructures and interface layers for polymer solar cells. A polymer solar cell structure involves several layers, from the transparent conducting oxide (TCO) to top metallic electrodes, from the hole (HIL) and electron interface layers (EIL) to the active polymers. Starting from the generic structure (TCO/HIL or EIL/Active polymers/EIL or HIL/Metal), a systematic study on over 10 materials, among which different TCOs, metal oxides, organic and inorganic compounds as interface layers, metals as top electrodes and different active polymers, was carried out.
Combining the most common materials in over 20 different architectures enabled me to clarify, thanks to support from simulations, the relationship between open circuit voltage and the difference between the work function values of the two opposite interface layers/contacts, a matter that until now was still under debate. Furthermore, innovative electrodes, active polymers and fabrication techniques have been here demonstrated to be promising candidates for polymer photovoltaics (PV). Not only improvement in solar cell performance was achieved, but also investigations on the influence of the electrode/active interfaces were carried out by electroabsorption (EA) spectroscopy to understand the physics behind the enhancement of the solar cell performances. Finally, a study on neutron radiation tolerance of polymer solar cells was investigated to demonstrate the feasibility for space applications.
The results of this thesis are an overall study of polymer PV. The approach used in this thesis can be extended to other photoactive and contact layers used in the polymer solar cells in order to clarify the electrode influence on other photovoltaic parameters (i.e. current density, fill factor and power conversion efficiency) and even to develop new promising materials.
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Mavundla, Sipho Enos. "One-Dimensional nanostructured polymeric materials for solar cell applications." Thesis, University of the Western Cape, 2010. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1088_1305888911.
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This work entails the preparation of various polyanilines with different morphologies and their application in photovoltaic solar cells. Zinc oxide (ZnO) with one-dimensional and flower-like morphology was also prepared by microwave irradiation and used as electron acceptors in photovoltaics devices. The morphological, structural, spectroscopic and electrochemical characteristics of these materials were determined by scanning electron microscopy (SEM), X-Ray diffraction (XRD), Raman, Fourier-transformed infrared spectroscopy (FTIR), ultraviolet and visible spectroscopy (UV-Vis), photoluminescence(PL), thermal gravimetric analysis (TGA) and cyclic voltammetry (CV) experiments. Devices fabricated from these materials were characterized under simulated AM 1.5 at 800 mW.
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Ong, Kok Haw. "Low band-gap donor polymers for organic solar cells." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6430.
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One of the key challenges of organic solar cells is their relatively low power conversion efficiency. One way to improve the efficiency of these cells is to develop donor materials with improved photon harvesting capabilities, well-located highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) energy levels, good hole transport characteristics and good processability. In this thesis, the design, synthesis and characterization of fifteen low band gap donor-acceptor type polymers are described. Two different acceptor moieties, 3,6- bis(thien-2-yl)-2,5-di-N-alkylpyrrolo[3,4-c]pyrrole-1,4-dione (DPP) and 2,1,3- benzothiadiazole (BT) were used in our polymer designs and the polymers were synthesised using the palladium-catalysed Stille cross-coupling method. The first series of polymers were random co-polymers of DPP and dithienothiophene. By tuning the solubility and absorption characteristics of the polymers, we achieved a polymer that gave power conversion efficiencies of up to 4.85 % when applied in solar cells. Low open-circuit voltages were obtained for these cells, hence the next series of polymers was designed with the aim of improving the open-circuit voltages. Although the lower HOMO levels of these polymers resulted in higher open-circuit voltages when applied in solar cells, the low hole mobility of the polymers and poor morphology of the polymer:fullerene films resulted in low solar cell power conversion efficiencies. Finally, a series of benzothiadiazole-oligothiophene polymers were synthesised. These polymers had high hole mobilities and wide absorption spectra. When these polymers were applied in organic thin-film transistors, good hole mobilities of up to 0.20 cm2/Vs were achieved, and when applied in solar cells, power conversion efficiencies of up to 6.2 % were achieved. These results show that benzothiadiazoleoligothiophene systems are promising candidates for both transistor and solar cell applications.
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Ng, Annie, and 吳玥. "Polymer blend film for photovoltaic applications optical characterization and solar cell performance." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196013.
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Sunlight is sustainable, clean and readily available energy source, which is one of the potential alternatives to the traditional energy sources. Recently, the organic photovoltaics (OPVs), in particular polymer solar cells (PSCs), have attracted increasing attention owing to their outstanding properties such as low cost, lightweight, flexible, allowing vacuum-free fabrication process and thin-film architecture. These advantageous material and manufacturing features of PSCs provide the opportunities for many novel applications. However, the lower power conversion efficiencies (PCEs) of PSCs compared to inorganic solar cells hinder their competition in the marketplace.
This thesis covers the basic principles of the PSC, strategies for enhancing PCEs as well as the recent development of PSCs. The importance of the source materials has been also demonstrated and discussed. Due to a large number of possibilities, limited resources and time, it is not feasible to do all the work experimentally. Therefore, for continuing advance development of PSCs, the device performance should be modeled as a function of material parameters, which requires the knowledge of material properties, in particular the complex index of refraction N= n - ik. Accurate determination of the optical functions of the active layers and light trapping layers commonly used in PSCs by using the spectroscopic ellipsometry (SE) has been demonstrated. In order to acquire reliable solutions, the methodology including multiple sample analysis, combinations of different measurement techniques, selection of models, the rigorous fitting procedures and the independent verification have been proposed. The obtained information can be used in the simulation to optimize device architectures, model device performance as well as characterize novel materials.published_or_final_version
Physics
Doctoral
Doctor of Philosophy
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Cui, Chaohua. "Conjugated polymer and small-molecule donor materials for organic solar cells." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/37.
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This thesis is dedicated to developing conjugated polymer and small-molecule donor materials for solution-processable organic solar cells. To begin with, a brief introduction of organic solar cells (OSCs) and an overview of donor materials development were presented in Chapter 1. In chapter 2, we used carbon-carbon triple bands as linkage of the TVT unit to develop a new building block, ATVTA. Small molecules S-03, S-04, and S-05 with ATVTA as building block showed broad absorption spectra and low-lying HOMO energy levels. S-01 with TVT unit and S-02 with AT2 as building block were also synthesized for clear comparison. OSCs devices based on S-01 and S-02 showed a Voc of 0.88 V and 0.89 V, respectively. The device based on S-03 exhibited a high Voc of 0.96 V, leading to a PCE of 2.19%. The devices based on S-04 and S-05 afforded a notable Voc over 1.0 V. The results demonstrate that ATVTA unit is a promising building block for extending π conjugation of the molecules without pulling up their HOMO energy levels. Chapter 3 focused on the development of 2D-conjugated small-molecule donor materials. The 2D-conjugated small molecule S-06 possesses excellent solution processability, broad absorption feature, respectable hole mobility and good film-forming morphology. The conjugated thiophene side chain not only effectively extends the absorption spectrum, but also lowers the HOMO energy level, which is desirable for obtaining high Voc. The BHJ OSCs based on S-06:PC70BM (1:0.5, w/w) afforded a high PCE of 4.0% and a notable FF of 0.63 without any special treatment needed. This preliminary work demonstrates that this kind of 2D-conjugated small molecules offer a good strategy to design new photovoltaic small molecule-based donor materials with high FF and Voc for high-efficiency OSCs. The consistently developed two 2D-conjugated small molecules S-07 and S-08 also possess low-lying HOMO energy levels. OSC device based on S-07:PC60BM (1:3, w/w) afforded a notable Voc of 0.96 V, with a PCE of 2.52%. BHJ devices based on S-08 will be fabricated and tested to investigate its photovoltaic properties in the near future. We developed a series of oligothiophenes with platinum(Ⅱ) as the building block in Chapter 4. These small metallated conjugated small molecules exhibited broad spectra and relatively low-lying HOMO energy levels in the range of –5.27 eV to –5.40 eV. Introducing platinum(Ⅱ) arylene ethynylenes as building block can be considered as an approach to obtain small-molecule donors with satisfactory absorption features and HOMO energy levels. Nevertheless, due to the low FF, the PCEs of these donor materials based devices are lower than 2%. Fine tuning the film morphologies of this kind of metallated small-molecule donor materials should be carried out to improve their photovoltaic performance. We addressed an efficient approach to improve the photovoltaic properties by side chain engineering in 2D-conjugated polymers in Chapter 5. Considering the fact that the Voc of PBDTTT based devices is less than 0.8 V, we introduced alkylthio substituent on the conjugated thiophene side chains of the 2D-conjugated copolymer to further improve the photovoltaic performance of the 2D-conjugated copolymers PBDTTTs. The weak electron-donating ability of the alkylthio side chains effectively down-shifted the HOMO energy level of PBDTT-S-TT by 0.11 eV in comparison to the corresponding polymer with alkyl substitution on the conjugated thiophene side chains. The PSC device based on PBDTT-S-TT showed an enhanced Voc of 0.84 V, which is among the highest one in the reported copolymers based on BDT and TT units, leading to an enhanced PCE of 8.42%. The results indicate that molecular modification by introducing alkylthio side chain will be a promising strategy to broaden the absorption, down-shift the HOMO energy level and increase the hole mobility of the low band gap 2D-conjugated polymers for further enhancing the photovoltaic performance of PSCs. PBDTT-O-TT-C and PBDTT-S-TT-C were developed to further study the conclusion. We found that OSC device based on PBDTT-S-TT-C with alkylthio side chain also demonstrated a high Voc of 0.89 V, with a PCE of 6.85% when processed with 3% DIO additive
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Barkhouse, D. A. R. "Enhancing Charge Separation and Transport in Polymer Solar Cells." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491338.
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This work investigates means of overcoming the problems of Short exciton diffusion length and low charge mobility in polymer solar cells. The first issue is addressed by using a novel polyphenylenevinylene (PPY) derivative, which has a permanent dipole on the repeat unit of the polymer, to dissociate excitons in the polymer bulk, rather than requiring exciton diffusion to a dissociating interface. The second is dealt with by adding a lithium salt to polymer/Ti02 devices to improve hole mobility. The photophysical characteristics and photovoltaic device performance of a PPY derivative with a fluorene sidegroup, with and without an electron withdrawing nitro moiety which bestows a larger dipole moment across the repeat unit of the polymer, are reported. The photoluminescence of the polymer with the nitro group (nitrofluoro-PPY) is lower than that of its non-nitro (fluoro-PPY) analogue by a factor of eight. Lightinduced electron spin resonance experiments show that the nitrofluoro-PPY has more photoinduced spins, indicating that the luminescence quenching is due to intramolecular charge separation. Photovoltaic devices made with the nitrofluoro-PPY are three times as efficient as those with the fluoro-PPY, mainly due to an increase in current. Both types of device are inefficient, similar to previously reported all-polymer devices, and their efficiency is greatly improved by the incorporation of a solubilized C60 electron transporting phase. The addition of a lithium salt (Li[CF3S02hN) to MEH-PPY/Ti02 solar cells drastically improves device performance by increasing both the fill-factor and shortcircuit current by up to 40%. The efficiency of Li[CF3S02hN modified devices is 1.05% under 80 mWIcm2 simulated solar illumination, twice that of control devices without the salt and the highest reported to date for any polymer/Ti02 solar cell. The improved performance is attributed to a large increase in the hole mobility in the polymer, as measured by space-charge-limited current measurements, in the presence of the lithium salt. Modification of devices with the salt LiCI04 is not as effective at improving device performance. Secondary ion mass spectroscopy studies suggest that this is due to poorer diffusion of lithium into the polymer layer for LiCI04 relative to Li[CF3S02hN. The novel charge separation polymers studied here may serve to inform the development of all-organic dyes, and lithium salt treatment of bulk heterojunction devices may lead to significant improvements in power conversion efficiency.
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Alsulami, Abdullah. "Solution processed hole extraction interfaces for polymer solar cells." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/13929/.
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Organic semiconductors often make poor ohmic contacts with electrodes due to the deep energy levels forming an energetic barrier at the interfaces between the organic layer and the electrode contact. The mismatch in energy levels at the interface was overcome by inserting PEDOT:PSS material as an anode interlayer for achieving good ohmic contact and selecting single types of charge carriers at the polymer-electrode interface. Despite the significant development that was observed in the OPVs performance, the residual moisture and the acidic nature of PEDOT:PSS can cause degradation of the organic films and therefore affect long term stability. Metal oxides were later suggested as alternative interlayers to the PEDOT:PSS which exhibited high performance and long lifetimes. However, many of the metal oxide studies reported in literature used vacuum deposition methods, such as thermal evaporation and sputter deposition, which are not necessarily desirable for large-scale production. This thesis shows that it is possible to deposit Vanadium oxide (V2Ox) from solution in ambient conditions requiring no post-deposition treatment and achieving comparable efficiency to the most widely used interlayer materials. Using a combination of spectroscopic techniques and device characterisation, it is shown that solutionprocessed V2Ox can be used to replace evaporated metal oxides in optoelectronic devices which are fabricated at high temperatures. The work also goes on to show that it is possible to solution-process nickel oxide from a nickel acetylacetonate precursor and obtain a power conversion efficiency > 5%. Finally, the lifetime study of OPV devices utilising various anode interlayer materials shows that the stability of optimised V2Ox devices can be comparable with other interlayer materials.
40
Schaffer, Christoph [Verfasser]. "Morphological Degradation in Polymer-Fullerene Solar Cells / Christoph Schaffer." München : Verlag Dr. Hut, 2017. http://d-nb.info/1135594805/34.
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Lander, Sanna. "Polymer/silicon hybrid solar cells : Fabrication and electrical properties." Thesis, Karlstads universitet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-46945.
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In this thesis, the process of fabricating PEDOT:PSS/c-Si hybrid solar cells has been investigated with the goal of performing a proof of concept as well as to determine the influence on solar cell performance of some processing parameters. Properties of PEDOT:PSS film formation and metal contact formation were investigated as a first step. Additionally, the surface passivation properties of PEDOT:PSS on n-Si have been studied and carrier lifetimes of 300 I denna uppsats har tillverkningen av PEDOT:PSS/c-Si hybridsolceller undersökts med målet att tillverka en fungerande solcell samt att bestämma påverkan på cellens prestanda av vissa processparametrar. Polymerfilmbildning och metallkontaktbildning undersöktes som ett första steg. Dessutom studerades polymerfilmens förmåga att passivera n-Si ytor, och livstider hos laddningsbärare på ca 300
42
Fukuhara, Tomohiro. "Charge Transport and Recombination in Crystalline Polymer Solar Cells." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263684.
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Khanyile, Sfiso Zwelisha. "Silicon nanowires by metal-assisted chemical etching and its incorporation into hybrid solar cells." University of Western Cape, 2021. http://hdl.handle.net/11394/8340.
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Philosophiae Doctor - PhDThe rapid increase in global energy demand in recent decades coupled with the adverse environmental impact of conventional fuels has led to a high demand for alternative energy sources that are sustainable and efficient. Renewable solar energy technologies have received huge attention in recent decades with the aim of producing highly efficient, safe, flexible and robust solar cells to withstand harsh weather conditions. c-Si has been the material of choice in the development of conventional inorganic solar cells owing to it superior properties, abundance and higher efficiencies. However, the associated high costs of Si processing for solar cells have led to a gravitation towards alternative organic solar cells which are cheaper and easy to process even though they suffer from stability and durability challenges. In this work, combination of both inorganic and organic materials to form hybrid solar cells is one of the approaches adopted in order to address the challenges faced by solar cell development.
44
Wang, Qiwei. "New functional molecules and polymers for organic light-emitting diodes and solar cells." HKBU Institutional Repository, 2010. http://repository.hkbu.edu.hk/etd_ra/1200.
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45
Aung, Pyie Phyo. "Monte Carlo Simulations of charge Transport in Organic Semiconductors." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1418272111.
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"study on polymeric solar cells." 2011. http://library.cuhk.edu.hk/record=b5894737.
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Cheng, Ka Wing = 聚合物太陽能電池的研究 / 鄭家榮."December 2010."
Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (leaves 93-96).
Abstracts in English and Chinese.
Cheng, Ka Wing = Ju he wu tai yang neng dian chi de yan jiu / Zheng Jiarong.
Abstract --- p.i
概要 --- p.iii
Acknowledgements --- p.iv
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- The Rise of Organic Photovoltaics --- p.1
Chapter 1.2 --- General Review on Organic Photovoltaics --- p.3
Chapter 1.2.1 --- Physics of Organic Photovoltaics --- p.4
Chapter 1.2.2 --- Performance Analysis --- p.10
Chapter 1.2.3 --- Calibration --- p.11
Chapter 1.2.4 --- Device Architectures --- p.14
Chapter 1.3 --- Morphology and Performance of Bulk Heterojunction Polymeric Solar Cells --- p.17
Chapter 1.3.1 --- Choice of Solvent --- p.17
Chapter 1.3.2 --- Effect of Annealing --- p.18
Chapter 1.4 --- The Quest of Higher Efficiency --- p.18
Chapter 1.5 --- Structure of This Thesis --- p.19
Chapter 2 --- Optical Properties in a Multilayered Solar Cell --- p.21
Chapter 2.1 --- Introduction --- p.21
Chapter 2.2 --- Electromagnetic Waves in a Multilayered Thin Film --- p.22
Chapter 2.3 --- Microcavity Effect --- p.33
Chapter 2.4 --- Conclusion --- p.34
Chapter 3 --- Improvement of Solar Cell Efficiency: Result of Simulation --- p.36
Chapter 3.1 --- Introduction --- p.36
Chapter 3.2 --- P3HT:PCBM Bulk Heterojunction Solar Cells --- p.36
Chapter 3.2.1 --- Standard Devices --- p.37
Chapter 3.2.2 --- Standard Devices with Inserted Silver Layer --- p.39
Chapter 3.2.3 --- Silver Layer Inserted Devices Without PEDOT:PSS ... --- p.44
Chapter 3.3 --- MEH-PPV:PCBM Bulk Heterojunction Solar Cells --- p.46
Chapter 3.3.1 --- Standard Devices --- p.46
Chapter 3.3.2 --- Standard Devices with Inserted Silver Layer --- p.50
Chapter 3.3.3 --- Silver Layer Inserted Devices Without PEDOTiPSS . . --- p.52
Chapter 3.4 --- Discussion --- p.54
Chapter 3.5 --- Conclusion --- p.56
Chapter 4 --- Experimental Results --- p.57
Chapter 4.1 --- Introduction --- p.57
Chapter 4.2 --- A General Study on Traditionally Structured Solar cell --- p.58
Chapter 4.2.1 --- Standard Bulk Heterojunction Devices --- p.58
Chapter 4.2.2 --- Effects of the Metal Electrodes --- p.59
Chapter 4.2.3 --- Effects of Annealing Time --- p.60
Chapter 4.3 --- Modified P3HT:PCBM Bulk Heterojunction Solar Cells --- p.61
Chapter 4.3.1 --- Optimized Standard Devices --- p.61
Chapter 4.3.2 --- Standard Devices with Inserted Silver Layer --- p.63
Chapter 4.3.3 --- Silver Inserted Devices Without PEDOTiPSS --- p.64
Chapter 4.4 --- Discussion --- p.68
Chapter 4.5 --- Conclusion --- p.71
Chapter 5 --- Conclusion --- p.73
Chapter 5.1 --- Suggestion of Future Works --- p.75
Chapter A --- Simulation Codes --- p.77
Chapter A.1 --- P3HT:PCBM (1:1) Standard Device --- p.77
Chapter B --- Instrumentation --- p.87
Chapter C --- Sample Preparation --- p.90
Bibliography --- p.93
47
Lin, Li-Yen, and 林立彥. "Design, Synthesis, and Exploitation of Small-Molecule and Polymeric Materials for Dye-Sensitized Solar Cells and Organic Solar Cells." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/35584876109448455117.
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博士國立臺灣大學
化學研究所
101
Increasing energy demands and concerns about global warming have been driving a great need to develop environmentally friendly renewable energy resources in the past few decades. Conversion of solar energy into electricity via photovoltaic technologies provides a sustainable approach to addressing these issues. Both dye-sensitized solar cells (DSSCs) and organic solar cells (OSCs) have been regarded as highly promising and cost-effective alternatives to the market dominant silicon-based counterparts. This dissertation describes my research efforts in the design, synthesis, and characterization of small-molecule and polymeric materials for DSSCs and OSCs, with the focus on the exploration of structure–property relationships and their correlations to device performance. It is organized as follows. Chapter 1 gives a brief overview of bandgap engineering of pi-conjugated aromatic systems. Chapter 2 deals with the design principles, synthesis, and characterization of three series of organic sensitizers as well as their application in DSSCs. Chapter 3 describes eight small-molecule donor materials for use in vacuum-deposited OSCs. Their synthesis, physical properties, and photovoltaic performance are discussed. Chapter 4 describes the synthesis and optoelectronic characterization of two p-type conjugated polymers as well as their use as donors in solution-processed polymer bulk heterojunction solar cells. Furthermore, a short summary of state-of-the-art photosensitizers for DSSCs as well as molecular donors and polymeric donors for OSCs is respectively presented in the beginning of Chapter 2, 3, and 4.
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Shih, Po-Ta, and 施柏達. "Synthesis of Polymeric Dispersants for Nanomaterials and Dye-Sensitized Solar Cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/95263436428150721802.
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博士國立臺灣大學
高分子科學與工程學研究所
103
“Dispersion technology” is considered as the key step in bottom-up process for self-assemblies and fabricating nanomaterial devices. Herein, dispersion of sp2 carbon materials, graphene and carbon nanotube (CNT), in aqueous or organic mediums is important process for utilizing nanomaterials in various downstream applications. Further, the performance of adding CNT and 2D platelet-like graphene as the nanoscale fillers to nanocomposites relies on the step of homogeneously dispersing the nanomaterials into their primary structure. Nanohybrids including silver nanoparticles decorated on the carbon nanotube (CNT) and platinum-on-graphene were fabricated by ionic excharge reaction and non-covalent method. These materials were investigated on dispersibility, particle size and distribution, electrical behavior, and the applications for dye-sensitized solar cells (DSSCs). There are two parts in this dissertation, aiming to investigate the dispersion of nanomaterials including nanoparticles such as silver nanoparticle (AgNP), titanium dioxide and platinum nanoparticle (PtNP), carbon materials such as carbon nanotube (CNT) and graphene and the sequential hybridization for the use in DSSCs. In the first part, two families of functional polymers for homogeneously dispersing CNT and graphene in aqueous medium were reported. The tandem procedures of dispersing CNT and then AgNPs were developed to prepare CNT-tethered AgNPs nanohybrids, which allowed the conductive application at low temperature (Chapter 3); the structural differences in chemical functionalities of the synthesized polymers were allowed to evaluate their ability for dispersing graphene by disrupting the π-π stacking aggregation. With the assistance of adding polyvinyl alcohol, the homogeneously dispersed graphene in water was fabricated into a dimensionally stable film exhibiting high conductivity, evidenced the dispersing ability of the synthesized oligomers as the polymeric dispersants. With the introduction of waterborne polyurethane, conductive and flexible graphene films were prepared. In addition, by utilizing the dispersing mechanism of graphene, graphene directly exfoliated from graphite was realized, and that prevents the inevitable structural defects and lowers the cost of graphene preparation (Chapter 4). In the second part, dispersion of nanomaterials applied on DSSCs was exploited to assess the dispersibility and the importance of dispersion. The dispersion of TiO2 nanoparticles to generate the functional films effectively allows the control of TiO2 particle size and pore size distribution in film matrix for suitable uses as photoanodes in DSSCs (Chapter 5). A dispersion of platinum-on-graphene was prepared in the presence of a polymeric dispersant and subsequent in-situ reduction of dihydrogen hexachloroplatinate to metallic platinum on the graphene surface. The platinum-on-graphene dispersion was coated on an FTO glass to prepare a counter electrode (CE) for a DSSC. The hybrid film of platinum nanoparticles and graphene nanoplatelets (PtNP/GN) showed a transparency of 70% at 550 nm, indicating its suitability as a CE material for a rear-illuminated DSSC (Chapter 6).
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Lin, Yi-Feng, and 林宜鋒. "Dye-Sensitized Solar Cells: Study of PEDOT-MeOH Films and Polymeric Ionic Liquid." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/xmds5a.
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碩士國立臺灣大學
高分子科學與工程學研究所
104
This thesis aimed to develop structured poly(hydroxymethyl 3,4-ethylenedioxythiophene) (PEDOT-MeOH) films as counter electrodes (CEs) and to synthesize an iodide-free polymeric ionic liquid (PIL) as gel electrolyte for the dye-sensitized solar cells (DSSCs) with low-cost, high efficiency, and long-term stability. This thesis is divided into two parts: PEDOT-MeOH films as CEs (Chapter 3) and PIL as gel electrolyte (Chapter 4). In the case of the PEDOT-MeOH films as CEs, a film of the hierarchical PEDOT-MeOH tube-coral array (TCA) was successfully synthesized via a template-free electro-polymerization technique. The PEDOT-MeOH TCA was designed to simultaneously possess (1) the enhanced conjugation on PEDOT main chain due to the electro-donating MeOH group, (2) the tube-like fast one-dimensional charge transfer pathways, and (3) the coral-like extended electro-active sites. For the application in DSSCs, PEDOT-MeOH TCA worked as an outstanding electro-catalytic CE for iodine/triiodine (I–/I3–) reduction. Thus, the DSSCs with the hierarchical PEDOT-MeOH TCA as the CE reached the highest power conversion efficiency (η) of 9.13±0.06%, which was even higher than that of the DSSC with a standard Pt CE (8.94±0.07%). Via rotating disk electrode analysis, the newly synthesized PEDOT-MeOH TCA film was found to have a lower intrinsic heterogeneous charge-transfer rate constant (k0), but extremely larger effective electro-catalytic surface area (Ae) than that of the standard Pt film. The PEDOT-MeOH TCA can be considered as a convincing replacement of the expensive Pt due to its high electro-catalytic ability, low cost, and simple fabrication process. In the case of the PIL as gel electrolyte, a polymeric ionic liquid, poly(oxyethylene)-imide-imidazolium selenocyanate (POEI-IS), was newly synthesized and used for a multifunctional gel electrolyte in a quasi-solid-state dye-sensitized solar cell (QSS-DSSC). POEI-IS has several functions: (1) acts as a gelling agent for the electrolyte of the DSSC, (2) possesses a redox mediator of SeCN−, which is aimed to form a SeCN−/(SeCN)3− redox couple with a more positive redox potential than that of traditional I−/I3−, (3) chelates the potassium cations through the lone pair electrons on the oxygen atoms of its poly(oxyethylene)-imide-imidazolium (POEI-I) segments, and (4) obstructs the recombination of photo-injected electrons with (SeCN)3− ions in the electrolyte through its POEI-I segments. Thus, the POEI-IS renders a high open-circuit voltage (VOC) to the QSS-DSSC due to its functions of (2), (3), and (4), and prolongs the stability of the cell due to its function of (1). The QSS-DSSC with the gel electrolyte containing 30 wt% of the POEI-IS in liquid selenocyanate electrolyte exhibited a high VOC of 825.50±3.51 mV and a high η of 8.18±0.02%. The QSS-DSSC with 30 wt% of POEI-IS retained up to 95% of its initial η after an at-rest stability test with the period of more than 1,000 h. This properly designed PIL paves as promising way for developing highly efficient and durable QSS-DSSCs.
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Jhou, He-Jyun, and 周和均. "Polymeric and Small Molecular Hole Transporting Layers for Organometallic Halide Perovskite Solar Cells." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/phv356.
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