何國川臺灣大學:高分子科學與工程學研究所李坤穆Lee, Kun-MuKun-MuLee2010-05-122018-06-292010-05-122018-06-292008U0001-1511200800520700http://ntur.lib.ntu.edu.tw//handle/246246/183134本論文主要探討各材料的改進或系統改變對染料敏化太陽電池光電轉換行為影響，同時也針對元件效率及穩定性進行探討。文的第一部份為針對染料敏化太陽電池進行最適化探討，藉由高分子分子量控制，製備不同孔徑分布之TiO2工作電極。其中以P2P1分布之TiO2工作電極有最佳效率表現，在電極含有光散射粒子條件下，其光電轉換效率可達9.04 %。並藉由雷射光物理分析及利用交流阻抗分析，發現P2P1-TiO2電極有最低之界面電子轉移阻抗及最長之電子壽命。 另一方面，在低溫製備TiO2工作電極製程方面，本實驗室首先提出將奈米碳管導入低溫製備之TiO2電極中並應用於染料敏化太陽電池。藉由控制奈米碳管分布(0.1 wt%)及Ti-前趨物比例 (TTIP/TiO2=0.08)，可製備出光電轉換效率達5.02%之低溫染料敏化太陽電池。 同時，我們亦針對Miyasaka教授團隊所開發之低溫TiO2漿料來製備低溫塑膠基材之染料敏化太陽電池，並以中央大學吳春桂教授實驗室所開發之SJW-E1染料進行最適化研究，同時針對TiOx緻密層、各種共吸附劑結構及元件穩定性進行探討。最佳化後之低溫塑膠染料敏化電池效率於100 mW/cm2光強度下可達6.31%，並發現以SJW-E1為染料之元件在光照穩定性測試下，比N719有更好的穩定性表現。文的第二部分乃針對中研院化學所林建村教授實驗室所合成之有機染料進行染料敏化太陽電池元件測試及光電化學性質探討。最佳元件表現可達6.15 % (相對於N3系統為7.86 %)。研究發現，當在第三oligothiophene接有arylamibes之染料，元件會有較高的開環電位。同時進行雷射光物理及交流阻抗分析推論在第三oligothiophene接有arylamibes之染料可以抑制於TiO2上的電子與氧化態的染料與I3-進行再結合反應。同時理論計算結果發現，在第三oligothiophene接有arylamibes之染料在在電子激發態時有較高之電荷傳遞效率。第五章中，將探討光譜互補式之染料共敏化行為於塑膠基材之低溫染料敏化太陽電池應用。研究發現，兩共敏化系統分別為N719/FL 與black dye/FL系統之染料敏化太陽電池之元件光電效能表現比使用單一種類染料的太陽電池來的高，並分別可達到5.10%與3.78%。然而在FL /Chl-e6共敏化系統便沒有電流加成現象，元件效率表現只介於兩種染料單一存在之間。並由交流阻抗分析此三種共敏化系統發現，N719/FL 與black dye/FL系統共敏化後，元件的TiO2特徵頻率與單一染料條件維持相同，甚至往更低頻位移。然而FL /Chl-e6共敏化系統之元件TiO2特徵頻率甚至比單一FL染料高，意味著FL /Chl-e6共敏化後因染料聚集現象使得電子於TiO2中的電子壽命更低。本文的第三部分為探討膠態高分子電解質之製備及應用於染料敏化太陽電池。此部分將分別討論兩種膠態高分子電解質系統。首先歸納在電解質的有機溶劑之各項物化性質中，donor number為影響染料敏化太陽電池表現之重要影響因素。同時，在PVDF-HFP膠態高分子電解質中，以有機碘鹽(TBAI)為氧化還原對之元件表現，比無機碘(LiI)之表現來的佳。在含有5 wt% 的PVDF-HFP條件下，可得與液態電解質相仿之效率表現。並且在含有0.8 M TBAI與0.12 M I2時有最佳電流表現。進而導入二氧化矽奈米粒子於PVDF-HFP電解質中，由於降低PVDF-HFP之結晶度，明顯增加了離子傳輸路徑，因此提升了離子擴散係數，並使得元件有更好的光電流表現。在100 mW/cm2的光照下，最佳光電流可達14.04 mA/cm2，開環電位0.71 V，光電轉換效率為5.97 %。 另外，以同時聚合法方式製備膠態高分子電解質研究中，將低黏度之反應溶液導入奈米孔洞之TiO2電極中，再進行聚合反應使電解質固化，期能解決高分子電解質與工作電極間之界面阻力以提升光電轉換電流。研究發現，以B4Br作為交聯劑所製備之膠態電解質由於具有微相分離現象，使得有較高之導離度及元件電流表現。藉由將具可反應性官能基結構的分子與染料共吸附，除了可以作為共吸附劑降低染料之聚集現象外，並可在電解質的聚合過程中與TiO2電極界面間形成化學鍵結，可有效降低界面阻抗使得光電流從7.72 mA/cm2提升至10.00 mA/cm2。為了降低TiO2電極內之離子傳遞阻力，本研究藉由導入不同含量之均一粒徑PMMA於TiO2電極中，經燒結後製備含有350 nm孔洞之TiO2電極。經實驗發現在PMMA/TiO2比例為3.75時有一最佳結果，使元件之光電轉換效率從3.61%有效地提升至5.81 %。最後在本文的第四部分，一系列之poly(3,4-alkylenedioxythiophene)導電高分子以電化學聚合法製備於FTO玻璃上，並將之作為染料敏化太陽電池之對電極進行探討。實驗發現元件以PProDOT-Et2作為對電極有最佳之效率表現為7.88 %與對白金對電極表現相當(7.77 %)。元件之FF很明顯的受到PProDOT-Et2電聚合電量之不同而改變，並且當電聚合電量高於80 mC/cm2時，因高分子薄膜之聚集現象，降低的氧化還原的活性面積，使得元件之光電流及光電轉換效率明顯下降。將PProDOT-Et2導電高分子薄膜用於低溫塑膠染料敏化太陽電池亦有類似的趨勢表現，其最佳光電轉效率在100 mW/cm2光強度下為5.20 %，相對於以白金對電極之染料敏化太陽電池為5.11 %。The main purpose of this thesis is to investigate the behaviors of new approaches in electrodes (working and counter), sensitizers and gel polymer electrolytes for dye-sensitized solar cells (DSSCs) and discussing the influences on the cell performance and stability of DSSCs. n the first part of this thesis (Chapter 2 and 3), the optimization of solar energy conversion efficiency of DSSCs was investigated by the tuning of TiO2 photoelectrode’s morphology. Double-layered TiO2 photoelectrodes were designed by the coating of TiO2 suspension incorporated with low and high molecular weight poly(ethylene glycol) as a binder. Among four types of TiO2 electrodes, the P2P1 showed the highest efficiency under the conditions of identical film thickness and constant irradiation. This can be explained by the larger pore size and higher surface area of P2P1 TiO2 electrode than the other materials and these two factors assist for the facile transport of I3-/I- ion couple through the TiO2 matrix. The best efficiency (h) of 9.04% for a solar cell was obtained by introducing the light scattering particles to the TiO2 electrode measured under AM 1.5G. s for the part of low-temperature fabricated DSSC, the TiO2 film with the TTIP/TiO2 molar ratio of 0.08 has the best conduction. Meanwhile, the charge transport resistance at the TiO2/dye/electrolyte interface increased as a function of the MWCNT concentration, ranged from 0.1 to 0.5 wt%, due to a decrease in the surface area for dye adsorption. The DSSC with the TiO2 containing 0.1 wt% of MWCNT resulted in a JSC of 9.08 mA/cm2 and a cell conversion efficiency of 5.02 %. On the other hand, TiO2 film prepared by using binder-free TiO2 paste which developed by Prof. Miyasaka’s group was also used in plastic DSSC to optimal the SJW-E1 dye which synthesized by Prof. Wu’s group. The effects of TiOx buffer layer and co-adsorbents as well as long-term stability of plastic DSSCs were investigated. The TiOx buffer layer not only benefited the adhesion between TiO2 thin film and ITO/PEN substrate but also reduced the electron recombination, resulting in the improvement of the FF and conversion efficiency of cells. The optimized solar cell based on SJW-E1 showed a high efficiency of 6.31 % at 100 mW/cm2 (AM 1.5G), and SJW-E1 based solar cell showed a better stability than that of N719 based after 500 h light soakingest.n the second part of this thesis (Chapter 4), the co-sensitization of dyes for the complementary in the spectral characteristics in plastic DSSCs was investigated. Two co-sensitization systems for the plastic DSSCs, including N719/FL and black dye/FL showed enhanced photovoltaic performances compared with that of each dyendividually. The optimal conversion efficiencies of N719/FL and black dye/FL DSSCs reached 5.10 % and 3.78 %, respectively, which were higher than that of individual sensitizers. However, for the system co-sensitized with FL and Chl-e6, the cell performances only lay in between that of each dye. From the EIS analysis, the characteristic frequencies (C.F.) at TiO2/dye/electrolyte interface for N719/FL and black dye/FL are kept the same or lower than that of individual dyes. While for the FL /Chl-e6 co-sensitized DSSCs, the C.F. were higher than that based on only FL, indicating that they had shorter electron lifetime in the TiO2 electrode after co-sensitization.n the third part of this thesis (Chapter 5), two kinds of gel polymer electrolytes were developed and used in DSSCs. At the beginning, it was found that the donor number of solvent in electrolyte is the one of the key factors that effect the photovoltaic performance of DSSC. Meanwhile, the quasi-solid state DSSCs were fabricated with polyvinyidene fluoride-co-hexafluoro propylene (PVDF-HFP) in methoxy propionitrile (MPN) as gel polymer electrolyte (GPE), tetrabutylammonium iodide/iodine as redox couple, 4-TBP as additive and nano-silica as fillers. The energyonversion efficiency of the cell with 5 wt% PVDF-HFP is comparable to that one obtained in liquid electrolyte system. Solar cell containing PVDF-HFP with 0.8 M ofBAI and 0.12 M of I2 shows maximum photocurrent. Moreover, the addition of 1wt% nano-silica is found to improve the at-rest durability and the performance of theolar cell. A photocurrent of 14.04 mA/cm2, a VOC of 0.71 V and an overall conversion efficiency of 5.97 % under 100 mW/cm2 irradiation was observed for the best performance of a solar cell in this work. On the other hand, the ionic conductivities and performances of DSSCs of GPEs prepared by in situ polymerization with different cross-linkers were investigated. The poly(imidazole-co-butylmethacrylate)-based GPE containing the B4Br cross-linker showed a higher ionic conductivity, due to the formation of micro-phase separation that resulted in an increase of ion transport paths in the GPE. Moreover, a co-adsorbent, (4-pyridylthio) acetic acid, co-adsorbed with N3 dye on the TiO2 electrode not only reduced dye aggregation, but also reacted with the cross-linkers in the GPE at the TiO2/GPE interface after gelling, thus the value of JSC significantly increased from 7.72 to 10.00 mA/cm2. In addition, in order to reduce the ionic diffusion resistance within the TiO2 electrode, incorporation of monodispersed PMMA in the TiO2 paste was considered. With the optimal volume ratio of PMMA/TiO2 (v/v = 3.75), the micro-porous TiO2 electrode exhibited larger pores (ca. 350 nm) uniformly distributed after sintering, and the ionic diffusion resistance within the TiO2 film could significantly be reduced. The cell conversion efficiency increased from 3.61 to 5.81% under illumination of 100 mW/cm2, an improvement of ca. 55 %.n the fourth part of this thesis (Chapter 6), a series ofoly(3,4-alkylenedioxythiophene) counter electrodes prepared by electrochemical polymerization on the fluorine-doped tin oxide (FTO) glass substrate were incorporated in the platinum-free DSSCs. Cells fabricated with a PProDOT-Et2 counter electrode showed a higher conversion efficiency of 7.88 % compared to cells fabricated with PEDOT (3.93 %), PProDOT (7.08 %), and sputtered-Pt (7.77 %) electrodes. The FF was strongly dependent on the deposition charge capacity of the PProDOT-Et2 layer, but the aggregation of PProDOT-Et2 in higher deposition capacities (> 80 mC/cm2) resulted in decreases in JSC and the cell conversion efficiency. Incorporating the best ProDOT-Et2 film (40 mC/cm2) as the counter electrode in plastic DSSC was compared and showed similar tendency as mentioned above. The cell fabricated with a PProDOT-Et2 counter electrode showed a higher conversion efficiency of 5.20 % compared with that fabricated with sputtered-Pt (5.11%) electrodes under the illumination of 100 mW/cm2 (AM 1.5G).Acknowledgementbstract (中文摘要) Ibstract (English) IVable of contents VIIist of tables XIVist of figures XVIIIomenclatures XXXIhapter 1 Introduction 1-1 Solar Cells 1-1-1 Photovoltaic Cells 4-1-2 Photoelectrochemical Cells for Solar Energy Conversion 6-1-2-1 Photochemistry of Semiconductor-Liquid Junctions 6-1-2-2 Factors that Determine Conversion Efficiency of a Solar Cell 8-1-3 Dye-Sensitized Solar Cells 10-1-3-1 Challenges to Further Improvement 14-1-3-2 Mechanisms and Models 15-2 Review of the Dye-Sensitized Solar Cells (DSSCs) 201-2-1 Mesoporous Photoanode 201-2-2 Dye/Sensitizer 27-2-2-1 Metal polypyridine complexes dye 27-2-2-2 Organic Dye 36-2-3 Electrolyte 41-2-4 Counter Electrode 46-3 Motivation and Research Objectives 50-4 Measurement of DSSC performance 53hapter 2 Preparation and Investigation on High Performance TiO2 Electrodes or DSSCs 55-1 Introduction 55-2 Experimental 562-2-1 Materials and Reagents 56-2-2 Preparation of TiO2 Pastes 56-2-3 Fabrication of Double-Layered TiO2 Electrodes and Cells 57-2-4 Analysis Methods and Instruments 58-3 Results and Discussions 61-3-1 The Electron Transport Kinetics of TiO2 Electrodes in DSSCs 61-3-2 Influence of TiO2 Coating Morphology on the Performance of DSSCs 68-3-2-1 Properties of P1 and P2 TiO2 Electrodes 68-3-2-2 EIS and laser Induced Transient Photovoltage Analysis 68-3-2-3 Photoelectrochemical Characteristics of DSSCs 73-4 Conclusions 77hapter 3 Development of Low-Temperature Fabricated TiO2 Electrodes for SSCs 78-1 Introduction 78-2 Experimental 803-2-1 Materials and Reagents 80-2-2 Preparation of TiO2 electrodes 80-2-3 Cell assembly of DSSCs 81-2-4 Instruments and Measurements 82-3 Results and Discussions 83-3-1 Effects of Different TTIP/TiO2 Molar Ratios on the Performance of SSCs 83-3-2 Effects of TiO2 Electrode Thickness on the Performance of DSSCs 92-3-3 Effect of Light Intensity on the Performance of DSSCs 93-3-4 Effects of Light Scattering Particles and Thermal Treated Conditions for the TiO2 Electrode 96-3-5 Incorporating Carbon Nanotubes in a Low-Temperature abrication Process for DSSCs 100-3-6 Stability and High Performance Plastic Dye-Sensitized Solar Cells ased on a High Light-Harvesting Capability Ruthenium Sensitizer 109-4 Conclusions 123papter 4 Investigation on Co-Sensitization and Light Harvesting for lastic Dye-Sensitized Solar Cells 124-1 Introduction 124-2 Experimental 127-2-1 Materials and Reagents 127-2-2 Sample Preparation 127-3 Results and Discussions 129-4 Conclusions 142hapter 5 Preparation and Characterization of Gel Polymer Electrolyte for SSCs 143-1 Introduction 143-2 Experimental 146-2-1 Materials and Reagents 146-2-2 Preparation of TiO2 Electrode and Gel Polymer Electrolytes 146-2-3 Cell assembling and Measurements 147-3 Results and Discussions 150-3-1 PVDF-HFP based Gel Polymer Electrolytes (GPEs) 150-3-2 Gel Polymer Electrolytes Prepared by In-Situ Polymerization andEffects of Micro-Porous TiO2 Electrode on DSSCs 174-3-2-1 Effect of the Cross-Linker Structures on DSSCs 174-3-2-2 Effect of Dual-Functional Co-adsorbent on DSSCs 176-3-2-3 Effect of Micro-Porous TiO2 Electrodes on DSSCs 178-4 Conclusions 181hapter 6 A High-Performance Counter Electrode based on oly(3,4-alkylenedioxythiophene) for DSSCs 182-1 Introduction 182-2 Experimental 184-2-1 Materials and Reagents 184-2-2 Preparation of Counter Electrodes and TiO2 Electrodes 184-2-3 Cell Assembly and Measurements of the DSSCs 185-3 Results and Discussions 187-3-1 Characterization of Different Conducting Polymer Films and the nfluence of the Deposition Charge Capacity on the Conformationnd Catalyst Effects 187-3-2 Influences of the Conducting Polymers as the Counter Electrodes and Electrodeposition Capacity on the Photovoltaic Performances f DSSCs 193-3-3 Photovoltaic Performances of Low-Temperature Fabricated Plastic SSCs with ProDOT-Et2 Counter Electrodes 199-4 Conclusions 202hapter 7 Conclusions and Suggestions 203-1 Conclusions 203-1-1 The effect of TiO2 Electrode Morphology and Preparing Parameterson Electron Transport Kinetic and Solar Cell Performance 203-1-2 Synthesis of Novel Organic Dyes and their Applications in DSSCs 204-1-3 Preparation and characterization of Gel Polymer Electrolytes 205-1-4 Development and Characterization the High PerformanceCounter Electrodes for DSSCs 206-2 Suggestions 206-2-1 Improvement of Photovoltaic Parameters 206-2-2 The Electrolyte/Mediator 207-2-3 The Dye Sensitizer 207hapter 8 References 209ppendix A Theoretic power conversion efficiency 239-1 Solar spectrum 239-2 Charge transfer and power efficiency 241eference 246ppendix B Effects of Co-adsorbate and Additive on the Performance of SSCs-A Photophysical Study 248-1 Introduction 248-2 Experimental 249-2-1 Materials and Reagents 249-2-2 Cell assembly of DSSCs 249-2-3 Measurement and Instruments 250-3 Results and Discussions 252-4 Conclusions 260eferences 261ppendix C Enhancing the Performance of DSSC based on a Novel Organic ye by Incorporating TiO2 Nanotube in a TiO2 Nanoparticle Film 263-1 Introduction 263-2 Experimental 264-3 Results and Discussions 266-3-1 The Photoelectrochemical Properties of FL dye1 and the hotovoltaic Performance of the DSSCs 266-3-2 The Influences of Incorporating the TiO2 Nanotube (TNT) in TiO2 Nanoparticle Film on the Cell Performance of the DSSCs 274-4 Conclusions 285eferences 286ppendix D Curriculum Vitae 289amp;#8195;ist of Tablesable 1-1 Various types of solar cells: materials, efficiency, and features. 3able 1-2 A partial list of fabricating methods in plastic DSSCs. 26able 1-3 A partial list of of Ru-based dyes for DSSCs. 31able 1-4 A partial list of organic dyes for DSSCs. 37able 1-5 A partial list of gel polymer electrolytes 44able 1-6 A partial list of typical performances of DSSCs with different ypes of counter electrodes. 49able 2-1 Cell performances of the DSSCs with TiO2 films annealed at ifferent temperatures. 63able 2-2 The specific surface area, pore diameter, pore volume and verage particle diameter of P1 and P2 TiO2 photoelectrodes btained from BET measurements and SEM micrographs. 70able 2-3 Performances of DSSCs with various TiO2 composite electrodes. 72able 2-4 Photovoltaic performances of DSSCs having two layers of P2P1 iO2 electrodes with and without light scattering particles. 75able 3-1 The BET data, electron lifetimes and cell performances of SSCs at 100 mW/cm2 based on different TTIP/TiO2 molar atios in the paste used for TiO2 electrode preparation. 84able 3-2 The dye loading, electron lifetimes and cell performances of SSCs (measured under 100 mW/cm2) based on different hickness of TiO2 electrodes. 92able 3-3 The photovoltaic performances and impedance data of the DSSCs ith low temperature fabricated TiO2 electrode containing arious amounts of MWCNTs measured under 100 mW/cm2. 104able 3-4 The dye loading on TiO2 electrodes and photovoltaic performances f plastic DSSCs based on SJW-E1 dye with various conditions f co-adsorbents under the illumination of 100 mW/cm2. 118able 4-1 The photovoltaic performances of plastic DSSCs based on arious dyes and co-sensitizers systems under the illumination of 00 mW/cm2. 135able 5-1 Photovoltaic parameters and electron lifetimes of DSSCs obtained ith different solvents. 152able 5-2 The electrolyte parameter and the cell performances of the SSCs based on gel polymer electrolytes with various wt% f PVDF-HFP. 157able 5-3 Cell performances of the DSSCs containing various concentrations f TBP. 165able 5-4 The electrolyte parameters and the cell performances of the SSCs based on gel polymer electrolytes containing different t% of nano-SiO2. 167able 5-5 Ionic diffusion coefficients of I- and I3-, and the cell performances f dye-sensitized solar cells (DSSCs) witholy(imidazole-co-butylmethacrylate) based GPEs containing arious cross-linkers and SiO2. 175able 6-1 Cell performances of DSSCs based on different kinds of ounter electrode materials. These cell performances were easured under illumination at 100 mW/cm2. 190able 6-2 The RDE analysis and photovoltaic parameters of plastic-DSSCs ased on PProDOT-Et2 with various deposited charge capacities. 200able A-1 Parameters of the maximum efficiency, able B-1 The photovoltaic performance of the DSSCs based on BD and L containing different concentrations of DCA. 255able B-2 The effect of addition of GuSCN in the electrolyte on the hotovoltaic performance of the DSSC (GuSCN = 0.2 M). 256able B-3 Comparison of electron lifetime and electron diffusion oefficient on the TiO2 electrode containing DCA in the absence nd presence of GuSCN. 259able C-1 Photoelectrochemical properties of FL and N3 dye. 269able C-2 The fitting data from Nyquist plot of the DSSCs based on arious amounts of TNT in nanoparticle TiO2 film measured under 00 mW/cm2. 278able C-3 The average electron lifetimes and solar cell performances of he DSSCs containing FL and N3 dye, respectively. 279able C-4 The photovoltaic parameters of the DSSCs with FL under ifferent incident light intensities. 281amp;#8195;ist of Figuresig. 1-1 Basic structure of a silicon based solar cell and its working mechanism. 5ig. 1-2 The three known methods by which solar energy can be convertednto usable chemical and/or electrical energy. 7ig. 1-3 Typical J-V behavior of a solar cell generated by measuring theurrent as an applied potential is scanned between the workingnd counter electrodes. 9ig. 1-4 Schematic diagram of structure and function of a typical TiO2ased dye-sensitized solar cell. 11ig. 1-5 The key factors of each component in DSSC. 12ig. 1-6 Photocurrent action spectra of nanocrystalline TiO2 films withoutnd with chemisorbed monolayers of ruthenium pyridyl-chargeransfer sensitizers. 13ig. 1-7 Band-edge positions of semiconductors with respect to severaledox couples in aqueous solution at pH 1. Positions are givenoth as potentials versus NHE and as energies versus the electronn vacuum. 22ig. 1-8 Surface and cross sectional SEM images of a rutile (a, b) and annatase (c, d) films coated on FTO glass and annealed at 500 oC. 22ig. 1-9 Comparison of J-V curves of DSSCs employing rutile and anataseilms of the same thickness under 1 sun illumination. 23ig. 1-10 (a) Absorption spectra of dye-covered rutile and anatase films.b) IPCE spectra of DSSCs based on rutile and anatase films. 23ig. 1-11 Comparison of the electron diffusion coefficient (De) of dyeensitized rutile- and anatase- films as a function of the JSC at80-nm illumination. 24ig. 1-12 Individual steps of lift-off and transfer process. In the upper row,he preparation of the transfer layer on the spare substrate with ahin gold layer, as well as the lift-off process, is depicted. In the lower row, the preparation of the second substrate with the adhesionayer and the transferred porous layer, as well as theubsequent low-temperature sintering, is illustrated. 25ig. 1-13 Molecular structures of (a) N3 and (b) black dyes. 28ig. 1-14 The carboxyl groups are directly coordinated to the surface titaniumons producing intimate electronic contact between the dye andhe semiconductor. 29ig. 1-15 Possible binding modes of a COOH group to a metal oxide (TiO2). 29ig. 1-16 Molecular orbital diagram for ruthenium complexes anchored to theiO2 surface by a carboxylated bipyridyl ligand. The visibleight absorption of these types of complexes is a metal-to-ligandharge transfer (MLCT) transition. 30ig. 1-17 Structure of the hole conductor spiro-OMeTAD. 42ig. 1-18 Framework of this dissertation 53ig. 2-1 Morphological structure of the different TiO2 electrodes obtainedy successive coating of P1 and P2 TiO2 pastes on FTO substrate. 60ig. 2-2 XRD patterns of the TiO2 film annealed at different temperatures. 62ig. 2-3 SEM images of the TiO2 film annealed at different temperatures. 62ig. 2-4 (a) EIS spectra of the DSSCs with TiO2 film annealed atifferent temperatures; (b) Equivalent circuit for (a). 64ig. 2-5 (a) the electron lifetimes and (b) electron diffusion coefficients ofare and dyed TiO2 film annealed at different temperatures. 66ig. 2-6 (a) the electron lifetimes and (b) electron diffusion coefficients ofare and dyed TiO2 film containing different contents of PEG. 67ig. 2-7 The SEM images showing the surface morphologies of P1 and P2iO2 electrodes, respectively, where P1 and P2 contain the binderEG with molecular weights of 20000 and 200000 respectively in the TiO2 paste. 69ig. 2-8 BJH desorption pore volume distribution of P1 and P2 TiO2 electrode. 69ig. 2-9 (a) Nyquest plots and (b) Bode phase plots of the DSSCs basedn various TiO2 electrode materials. 71ig. 2-10 The transient photovoltage measurement of various TiO2 electrodesnder identical conditions. 72ig. 2-11 The IPCE action spectra of DSSCs having P2P1 TiO2 electrodes withnd without light scattering particles, respectively. 75ig. 2-12 J-V curve for the DSSC exhibiting the best performance. 76ig. 3-1 SEM images of TiO2 electrodes prepared in different TTIP/TiO2olar ratios (a) 0.08 and (b) 0.20. 85ig. 3-2 Electrochemical impedance spectra of DSSCs based onifferent TTIP/TiO2 molar ratios measured at VOC, 100 mW/cm2. (a)nd (b) are Nyquist plots. Fig 3-2(b) is an enlargement of Fig. 3-2(a).c) is Bode phase plot. 88ig. 3-3 Transient photovoltage measurements of various TiO2lectrodes prepared with different molar ratios of TTIP/TiO2. 90ig. 3-4 (a) electron transport resistance, (b) capacitance, and (c) time constantf DSSCs based on different TTIP/TiO2 molar ratios were obtainedrom impedance measurement in the dark by applying various biases. 91ig. 3-5 Electrochemical impedance spectra of DSSCs based on varioushickness of TiO2 electrodes measured at VOC, 100 mW/cm2. (a)yquist plot and (b) Bode phase plot. 95ig. 3-6 Electrochemical impedance spectra of DSSC based on TTIP/TiO2olar ratio of 0.08 and the TiO2 thickness of 17.2 mm measured under0, 60, and 100 mW/cm2. (a) Nyquist plot and (b) Bode phase plot. 96ig. 3-7 (a) The variation of current density and cell conversion efficiencyf DSSCs based on the TiO2 electrode treatment at 150 oC forarious annealing times up to 12 h. (b) The XRD patterns of P25iO2 without/with sintering at 500 oC for 0.5 h are shown, respectively,n curves (1) and (2). The XRD patterns of TiO2 film obtained fromhe TTIP precursor and sintered at 150 oC for 0.5 h and 12 h arehown, respectively, in curves (3) and (4). 98ig. 3-8 (a) The sketch plots of different TiO2 electrodes. (b) J-V curves ofSSCs based on different collocations of TiO2 electrodes. 99ig. 3-9 TEM images of (a) MWCNT and (b) P25 TiO2. (c) and (d) are theEM images of the side view of 0.1 wt% MWCNT/TiO2 film. 101ig. 3-10 Electrochemical impedance spectra of the DSSCs based oniO2 electrode with different weight percents of MWCNTs measuredt -0.8 V, 100 mW/cm2. (a) Nyquist plot and (b) Bode phase plot. 104ig. 3-11 Transient photovoltage measurements of the DSSCs with variousiO2 electrodes prepared with or without 0.1 wt% MWCNT. 105ig. 3-12 The EIS measurement of the DSSCs with various TiO2 electrodesaving various ratios of MWCNTs in the dark and applied -0.8 V. 106ig. 3-13 The time constant of electron in TiO2 electrode of the DSSCs basedn different wt% of MWCNTs. The impedance measurement and the calculation are recorded in the dark and various applied biases. 107ig. 3-14 EIS of the DSSCs based on 0.1 wt% MWCNT/TiO2 film withifferent electrolytes measured at -0.8 V, 100 mW/cm2. (a) Nyquistlot; (b) Bold phase plot. 108ig. 3-15 The J-V curves of DSSCs based on 0.1 wt% MWCNT/TiO2 filmith different electrolytes. 108ig. 3-16 The cell performances of plastic DSSCs based on SJW-E1 dyeith various thicknesses of low temperature fabricated TiO2 films:a) JSC and energy conversion efficiency, (b) IPCE active spectra. 110ig. 3-17 The properties of ITO/PEN substrates with and without sputterediOx film. (a) The transmittances in the region of 350-800 nm. (b)he CV measurement in AN solution containing 10 mM LiI, 1 mM I2nd 0.1 M LiClO4. 113ig. 3-18 The photovoltaic performances of plastic DSSCs based onTO/PEN substrates with and without sputtered TiOx film. Thehickness of TiO2 electrode was ca. 7 mm. 114ig.3-19 The chemical structures of co-adsorbents. 114ig.3-20 Absorption spectra of SJW-E1 dye with or without DCA on TiO2ilms (ca. 2 mm thick) and in DMF, respectively. 115ig.3-21 The optimal photovoltaic performances of plastic DSSCs basedn SJW-E1 and N719, respectively. The composition of electrolyteas 0.4 M LiI+0.4 M TBAI+0.02 M I2+0.3 M NMB in AN. (a)-V curves and (b) the IPCE spectra. 119ig.3-22 The relationship of electron lifetimes in TiO2, and photocurrentsnd energy conversion efficiencies of plastic DSSCs betweenifferent light intensities. 120ig. 3-23 The at-rest stability of plastic DSSCs based on SJW-E1 and719, respectively. 121ig. 3-24 The full sunlight soaking stability test of plastic DSSCs based onJW-E1 and N719, respectively, measured continuously under00 mW/cm2 irradiation. 122ig. 4-1 The chemical structures of sensitizers used in this study. 126ig. 4-2 The cell performances of plastic DSSCs based on FL witharious thicknesses of low temperature fabricated TiO2 films: (a) JSCnd energy conversion efficiency, (b) IPCE active spectra. 130ig. 4-3 The absorbation of individual and co-dyes of N719, black dyend FL. 131ig. 4-4 The J-V curves of plastic DSSCs based on co-sensitizers andndividual dyes. 133ig.4-5 (a) The IPCE active spectra of plastic DSSCs based on sequentialipping, first in N719 solution for 10 min and then in FL solutionor different dipping times. (b) The IPCE active spectra oflastic DSSCs based on sequential dipping, first in N719 solutionor different dipping times and then in FL solution for 10 min. 134ig.4-6 The IPCE active spectra of plastic DSSCs based on sequentialipping, first in black dye solution for different dipping times and then in FL solution for 10 min. 136ig.4-7 (a) The absorption spectra of FL and Chl-e6 with and without CAn ca. 2 mm TiO2 film. 138ig.4-8 EIS analysis of DSSCs based on various co-sensitization systems:a) N719 and FL, (b) black dye and FL, and (c) FL and Chl-e6 respectively. 141ig. 5-1 (a) Transient photovoltage of DSSCs with different solventsnder identical condition. (b) The dependence of the JSC of the DSSCn electron lifetime of the TiO2 electrode in different solvents. 153ig. 5-2 (a) and (b) shown the dependence of JSC of the DSSC on dielectriconstant and viscosity of different solvents, respectively; (c), (d), &f) shown the dependence of the donor number of differentolvents against the VOC, JSC & Rct2 of the DSSCs. (e) shownhe relationship between the donor number of solvents andhe electron lifetimes in TiO2 electrode in respective solvents. 154ig. 5-3 The absorption spectra based on DMSO, DMF and DMA, respectively indicating the dye desorption from the TiO2 photoelectrode. 155ig. 5-4 The Bode phase plots of the DSSCs based on AN, DMA, DMFnd DMSO solvents, respectively. 155ig. 5-5 Electron lifetimes in the TiO2 electrodes of the DSSCs withifferent wt% of PVDF-HFP in electrolytes. 157ig. 5-6 Conductivities of electrolytes and the current densities of theSSCs based on various concentrations of (a) TBAI and (b)I2, respectively. 160ig. 5-7 Electron lifetimes and electron diffusion coefficients based onarious concentrations of I2. 161ig. 5-8 (a) Nyquist plots and (b) Bode phase plots based on differentoncentrations of TBAI. 163ig. 5-9 (a) Nyquist plots and (b) Bode phase plots based on differentoncentrations of I2. 164ig. 5-10 Plot of conductivity vs. temperature with various amounts of SiO2anoparticles. 166ig. 5-11 (a) Nyquist plots (including fitting curves) and (b) Bode phaselots based on gel polymer electrolytes with various wt% SiO2. 168ig. 5-12 At-rest stability of the DSSCs based on GPE with/without SiO2. 170ig. 5-13 The variations of Rct2 and capacitance of the DSSCs storage at 70 oCor several days. 170ig. 5-14 Bode phase plots of the DSSCs based on (a) PVDF-HFP and (b)VDF-HFP/1% nano-SiO2 electrolytes, respectively, for thetorage temperature at 70 oC. 172ig. 5-15 Electron lifetimes and electron diffusion coefficients of the DSSCsased on (a) PVDF-HFP and (b) PVDF-HFP containing 1 wt%iO2 electrolytes for the storage temperature at 70 oC. 173ig. 5-16 (a) Cell performances of dye-sensitized solar cells (DSSCs) witharious concentrations of PAA in N3 dye solutions for co-adsorptionn TiO2 electrodes under illumination of 100 mW/cm2. The inset shows the UV-vis absorbance spectra of the N3 dye on TiO2 filmith various PAA concentrations. (b) The EIS analysis of DSSCsith various concentrations of PAA in N3 dye solutions foro-adsorbing on the TiO2 electrodes. 177ig. 5-17 SEM images of TiO2 electrodes with different morphologies preparedy incorporating various amounts of mono-dispersed PMMAarticles (350 nm) in TiO2 pastes. The volume ratios of PMMA/TiO2re: (a) 0.05, (b) 0.20, (c) 1.00, (d) 2.00, (e) 3.75, and (f) 5.00. 179ig. 5-18 (a) Cell performances of dye-sensitized solar cells (DSSCs) withifferent morphologies of TiO2 electrodes. The inset shows the IPCEsf the DSSCs. (b) Comparison of short-circuit current density (JSC)nd cell conversion efficiency (%) of DSSCs with differentiO2 electrodes. (c) Relationship between Rct2 and differentiO2 electrodes. The inset shows the corresponding EIS results. 180ig. 6-1 The polymerization of poly(3,4-alkylenedioxythiophene)s (PXDOTs).186ig. 6-2 The top view SEM images of various thin film materials: (a) Pt100 nm), (b) PEDOT (40 mC/cm2), (c) PProDOT (40 mC/cm2), andd) PProDOT-Et2 (40 mC/cm2). 188ig. 6-3 (a) CVs of iodide species on different electrodes and (b)onsecutive 100 CVs of I-/I3 for PProDOT-Et2 film at a scan ratef 100 mV/s and (c) the relationship between cycle times and theedox peak currents. 192ig. 6-4 (a) The CVs of iodide species on ProDOT-Et2 film with various scan rates in acetonitrile solution of 10 mM LiI, 1 mM I2 and 0.1 MiClO4. (b) Peak current as a function of scan rate in CV tests ofig. 7-3 (a). 194ig. 6-5 SEM images of PProDOT-Et2 films with various depositionharge capacities (×10,000): (a) 10, (b) 20, (c) 40, (d) 80, (e) 120,f) 160, and (g) 200 mC/cm2. (h) Image of sputtered-Pt (100 nm)or comparison. 195ig. 6-6 (a) The J-V curve of DSSCs based on PProDOT-Et2 counterlectrodes with different deposition charge capacities, andummarized in (b) The VOC and FF of the DSSCs vs. theeposition charge capacity and (c) the JSC and cell conversionfficiency of DSSCs vs. the deposition charge capacity. 197ig. 6-7 EIS measurements of dye-sensitized solar cells (DSSCs). (a) Theeries resistance of the device (RS) and the charge transfer resistancet the counter electrode/electrolyte interface (Rct1) fitted from theyquist plots. (b) Bode phase plot. 198ig. 6-8 EIS measurements of plastic DSSCs based on PProDOT-Et2 films. 200ig. 6-9 The IPCE spectra of plastic DSSCs with Pt and ProDOT-Et2 asounter electrode, respectively. 201ig. 6-10 The at-rest stability plastic DSSCs with Pt and ProDOT-Et2 asounter electrode, respectively. 201ig. A-1 Air mass definition. 240ig. A-2 The solar spectra at AM 0 and AM 1.5 plotted from the table in the literature 240ig. A-3 The geometry that defines the standard for the terrestrial solarpectral irradiance at air mass 1.5 for a 37° tilted surface. 241ig. A-4 Conversion efficiency of solar cell materials versus band gap foringle junction cells 244ig. B-1 The absorption spectra of (a) BD adsorbed on a 5 mm TiO2 film andb) FL adsorbed on a 1 mm TiO2 film. 253ig. B-2 Plots of (a) the lifetime and (b) the diffusion coefficient of electron onhe TiO2 vs. concentrations of the DCA in both BD and FL. 257ig. B-3 The dark current observed from the I-V curve of the FL sensitizedSSC containing DCA in the absence and presence of GuSCN. 259ig. C-1 (a) TEM image of well dispersed TiO2 nanoparticle and (b) SEMmage of nanoparticle TiO2 film. 267ig. C-2 The XRD pattern of the TiO2 nanoparticle after sintering at 500 oC. 268ig. C-3 The transparent spectra of nanoparticle TiO2 film withifferent thicknesses. 268ig. C-4 The absorption spectra of FL dye1 in THF solution and on TiO2 film. 269ig. C-5 The relationship between the quantity of dye adsorption on the TiO2ilm and cell conversion efficiencies against the soaking concentrationf the TiO2 film in dye solution at 25 oC. 271ig. C-6 (a) The change of normalized absorption maximum value andhe absorption maximum wavelength with the concentration ofye solutions. (b) the relationship of photovoltaic parameters of the DSSCs with the concentration of dye solutions. 272ig. C-7 Cyclic voltammograms of FL dye1 anchored on 4 mm TiO2 film.can rates (from inner to outer): 50, 100, 200, 300, 400 and 500 mV/s,espectively. The inset shows the dependence of anodic peak currentsn scan rates. 273ig. C-8 TEM and SEM images of the TiO2 nanotube (TNT). 275ig. C-9 XRD pattern of the TiO2 nanotube (TNT) after sintering atarious temperatures. 275ig. C-10 The solar cell performances of FL based on nanoparticle TiO2ilm incorporating various amount of TNT. 276ig. C-11 The effects of the TiO2 film thickness on short circuit currentensity (JSC), open circuit voltage (VOC), fill factor (FF) andell conversion efficiency (h) of the DSSCs. 278ig. C-12 The average electron lifetimes of FL and N3 dye. 279ig. C-13 Action spectrum of IPCE of the DSSCs based on FL and N3 dye. 281ig. C-14 EIS analysis of the DSSCs under different light intensities. (a)yquist plot and (b) Bode phase plot. 283ig. C-15 The at-rest stability of the DSSC with FL dye1 based on 4 mm TiO2ilm for 50 days. 284application/pdf18820674 bytesapplication/pdfen-US染料敏化太陽電池二氧化鈦電極敏化劑有機染料共敏化膠態電解質對電極導電高分子交流阻抗分析暫態光電流/光電為分析Dye-sensitized solar cells, TiO2 electrodeSensitizerOrganic dyeCo-sensitizationGel polymer electrolyteCounter electrodeConducting polymerElectrochemical impedance spectroscopy (EIS)Transient photovoltage/photocurrent analysis.[SDGs]SDG7thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/183134/1/ntu-97-D93549007-1.pdf