Surface Metallization of Polyimide as a Photoanode Substratefor Rear-Illuminated Dye-Sensitized Solar Cells

Plastic film is promising as a photoanode substrate of dye-sensitized solar cell (DSSC) for flexible applications, while a lowtemperaturesintering process is generally adopted for the TiO2 mesoporous film due to unstable thermal property of general plastics.This study demonstrates that typical high-temperature TiO2 sintering can be adopted for preparing the photoanode when using asurface-metallized polyimide (PI) film. A Sn/Ni bi-layer is formed on a PI film via a chemical process as the conductive layer. TheSn/Ni-coated PI photoanode can withstand high-temperature TiO2 sintering at a peak temperature of 430◦C for 30 min withoutsignificant visual deformation due to high thermal stability of PI and strength reinforcement caused by surface metallization. TheDSSC employing the Sn/Ni-coated PI film as the photoanode substrate reaches an energy conversion efficiency of 3.44% under1 sun rear-side illumination

Fabrication Techniques of Electrodes for Solar Cells

隨著天然能源的存量不斷減少，各種替代性能源的研究就一直不停地被嘗試著，其中又以太陽能最被大家視為未來最有潛力的能源來源。M. Gratzel於 1990年開始研究新一代的太陽能電池—染料敏化太陽能電池(Dye-sensitized Solar Cells, DSSC)，相較於傳統的矽晶型太陽能電池，DSSC因具備了製程簡單、材料便宜、發電效能受光照角度的影響小以及在低光量下具有較好的光電轉換效率等特點而更被受到重視。這20多年的研究已成功地將DSSC的應用融入人們的生活中，產品可大到置於建築物的玻璃牆上供給大樓的部份用電，小則用於電腦的無線鍵盤。為了使各類型產品能提供最佳的發電效能，DSSC的研究從嘗試各種軟硬基材、長效型電解質、降低製程成本、電池封裝方法等方向，藉由改變不同的製程方式以提升DSSC的應用性。 本論文的研究主題為「太陽能電池的電極製備技術」，共分為四個研究方向，是以利用不同實驗方法製備出適用於染敏電池及高分子太陽能電池(Polymer Solar Cells, PSC)的各種電極。第一部份為利用化學鍍濕製程方法再搭配簡易的離子交換法於不導電之PI軟板基材上製備出可導電之Ni/Pt雙層結構的軟板對電極，成功地降低白金成本，使電池效能達到7%，並擁有良好的片電阻(0.173 Ω/?)及電荷轉移阻抗(0.38 Ωcm2)。 為了製備出全軟板的DSSC，在第二部份的實驗中藉由室溫下即可進行的電泳共鍍法(Electrophoretic co-deposition, EPD)同時鍍上ZnO/TiO2這兩種奈米金屬氧化物形成一適用於低溫製程的複合結構光電極；另外也鍍上大尺寸TiO2顆粒(100nm)作為光電極之散射層以更進一步提升電池效能。 第三部份則是將高分子太陽能電池中具有良好電子傳遞性的電子傳導層，添加於染敏電池的光電極，藉著浸泡TiCl4溶液於FTO基材表面製備出一緻密的奈米TiO2薄膜，增加了電極基材的光穿透性及與TiO2網印電極的接附性，幫助光電極有更好的電子傳遞效果，並提升了約15%的光電流密度以及14%的效率值。 第四部份的研究是延續第三部份實驗的方向，於反式高分子(有機)太陽能電池(Inverted Polymer Solar Cells, PSC)內添加兩種不同的表面修飾材料(Nb2O5、PEIE)於陰極緩衝層(Cathodic buffer layer, CBL)之電極上，並搭配混摻兩種不同材料(ZnO、Ta2O5)比例做為CBL一起製備成高分子太陽能電池，此兩種表面修飾材料可使PSC之效能皆增加了15%以上。Owing to the exhaustion of natural energy resources, people are trying any research for the substitute energy resource, especially in solar energy. Dye-sensitized solar cells (DSSC) with much better advantages than silicon solare have gotten lots of attention because of its convenient fabrication, low-cost materials, any angle of light illumination and high efficiency with low light intensity since M. Gratzel introduced it at 1990s. In the past two decades, people did kinds of research to make DSSC to get into our lifes, such as larger modules, which is placed on the wall of building to provide electricity, or smaller modules for wireless keyboard of computer or tablelet. There are lots of researchs in DSSC with ifferent flexible or rigid electrodes, long-terrn typed electrolytes, low-cost fabrication and the sealed technique for extending lifetime. The purposes of above researchs are the ways to generate the best power conversion efficiency and increase the applications of DSSC. There are four parts in my thesis, I fabricate suitable electrodes for DSSC and inverted Polymer solar cells (PSC). First part showed surface metallization of Ni/Pt on a insulated polyimide is carried out via a wet chemical process, where top Pt acts as the catalyst and bottom Ni is the conduction/light-reflection layer. This Ni/Pt bi-layer prepared as counterelectrode for DSSC successfully reduced the amount of Pt loading and made efficiency to 7%, and lowered its sheet resistance (0.173 Ω/?) and charge transfer resistance (0.38 Ωcm2). In order to fabricate the whole flexible DSSC, the Electrophoretic-co-deposition (EPD) process, a low-temp method for making a complex structured photoanode, was used in second part. ITO glass was deposited with two kinds of nano particles (ZnO and TiO2) together for the photoanode by EPD. Larger TiO2 particles (100nm) deposited on the top of nano particles layers were used as scattering layer to form a low-temp-processed photoanode and increased the performance of DSSC. Third part showed the elelctron transporting layer (ETL) of PSC added on FTO substrate for photoanode in DSSC. The ultrafine ETL on FTO which has good electron mobility was formed by immersing in TiCl4 solution and also raised the light transparency and the adhesion between FTO and screen-printed TiO2 layers. When the ETL added in DSSC, it increased the photocurrent and efficiency with 15% and 14%, respectively. Fourth part showed the results of two kinds of surface modification materials (Nb2O5, PEIE) added into PSC, which was also used blended metal oxides (ZnO, Ta2O5) as cathodic butter layer (CBL). Nb2O5 and PEIE were benefit for PSC and raised its efficiency over than 15%.誌謝 I 摘要 II Abstract III 目錄 IV 圖目錄 VI 表目錄 VIII 第一章、緒論 1 1.1 前言 1 1.2 研究動機與目的 2 第二章、文獻回顧 4 2.1 染料敏化太陽能電池 4 2.1-1 染敏太陽能電池發展簡介 4 2.1-2 染敏太陽能電池結構介紹 4 2.1-3 染敏太陽能電池運作機制 5 2.1-4 影響染敏太陽能電池效能主因 6 2.2 太陽能電池之效能參數 8 2.2-1 太陽輻射照度 8 2.2-2 太陽能電池效能表現 8 2.3 染敏太陽能電池之各元件介紹 10 2.3-1 光電極 10 2.3-2 對電極 13 2.3-3 染料 23 2.3-4 電解液 24 2.3-5 封裝材料 25 2.4 化學鍍原理介紹 26 2.4-1 電鍍 26 2.4-2 無電鍍 26 2.4-3 化學置換法沉積 27 2.4-4 電泳沉積 28 2.5 高分子太陽能電池 29 2.5-1 高分子太陽能電池發展簡介 29 2.5-2 高分子太陽能電池結構介紹及運作機制 30 第三章、實驗方法與分析設備 31 3.1 以化學鍍法於聚亞醯胺上製備鎳/鉑軟板對電極應用於染敏太陽能電池 31 3.1-1實驗方法 31 3.1-2電池量測與分析 36 3.2電泳共鍍法沉積二氧化鈦及氧化鋅複合光電極應用於低溫染敏太陽能電池 37 3.2-1實驗方法 37 3.2-2電池量測與分析 39 3.3於光電極上添加緻密奈米TiO2薄膜並製備出高效率染敏太陽能電池 41 3.3-1實驗方法 41 3.3-2電池量測與分析 42 3.4對陰極緩衝層進行不同的表面修飾以改善高分子太陽能電池之效率 43 3.4-1實驗方法 43 3.4-2電池量測與分析 46 第四章、實驗結果與討論 47 4.1以化學鍍法於聚亞醯胺上製備鎳/鉑軟板對電極應用於染敏太陽能電池 47 4.1-1 PI表面Ni金屬化之製程 47 4.1-2 Pt置換反應之探討 55 4.1-3各鍍層之機械強度分析 60 4.1-4各Pt軟板對電極之電性分析 61 4.2電泳共鍍法沉積二氧化鈦及氧化鋅複合光電極應用於低溫染敏太陽能電池 65 4.2-1電泳沉積法(EPD)製程之前處理 65 4.2-2 EPD奈米顆粒製程之探討 68 4.2-3各EPD光電極之電性分析 70 4.3於光電極上添加緻密奈米TiO2薄膜並製備出高效率染敏太陽能電池 73 4.3-1緻密奈米TiO2薄膜之表面性質分析 73 4.3-2緻密奈米TiO2薄膜光電極之光電性質分析 76 4.4對陰極緩衝層進行不同的表面修飾以改善高分子太陽能電池之效率 80 4.4-1各陰極緩衝層之性質分析 80 4.4-2各表面修飾層對高分子太陽能電池之影響 82 第五章、總結論 87 參考文獻 89 附錄 102 圖目錄 圖1.1-1 目前各主要能源的消耗比例(2011) 1 圖2.1-1 DSSC結構示意圖 5 圖2.1-2 DSSC之運作機制圖 6 圖2.1-3 DSSC照光前後能階示意圖 6 圖2.1-4 電子的損失路徑(a,b,c)與理想路徑(1,2,3)之動力學平衡示意圖 7 圖2.2-1 標準太陽光頻譜照度圖 8 圖2.2-2 電流-電位曲線圖 9 圖2.3-1 半導體與pH=1之電解液接觸後之能帶表 13 圖2.3-2 N719和black dye結構圖 23 圖2.3-3 Porphyrin dye結構圖 23 圖2.4-1 化學置換反應之示意圖 27 圖2.5-1 PSC中不同p-n junction界面示意圖 29 圖2.5-2 傳統式(conventional)和反式(inverted)PSC之結構 29 圖3.1-1 PI軟板之金屬化製程 32 圖3.1-2 PI軟板之化學鍍製程 32 圖3.1-3 鎳/鉑軟板對電極之DSSC組裝流程 35 圖3.1-4 白金軟板對電極之實驗比較流程 35 圖3.2-1 EPD實驗裝置圖 38 圖3.2-2 EPD之光電極製程 38 圖3.2-3 電泳沉積光電極之DSSC組裝流程 39 圖3.4-1 高分子太陽能電池之製備流程示意圖 45 圖3.4-2 高分子太陽能電池之製備完成照片 46 圖4.1-1 化學置換搭配高溫氣相還原法之示意圖與表面結構分析 47 圖4.1-2 各表面處理步驟之PI表面情形 49 圖4.1-3 Pt seed layer經H2PtCl6溶液浸泡、高溫熱處理之表面型態 49 圖4.1-4 Ni和Pt seed layer分別經H2PtCl6溶液浸泡、高溫熱處理之PI表面型態 51 圖4.1-5 Ni和Pt seed layer分別經H2PtCl6溶液浸泡、高溫熱處理之TEM橫截面 52 圖4.1-6 Ni seed layer之最佳表面型態 52 圖4.1-7 不同電流於Ni seed layer上之電鍍表面型態 53 圖4.1-8 無電鍍 Ni之表面型態 53 圖4.1-9 電鍍 Ni之表面型態 54 圖4.1-10 Ni/PI之橫截面型態 54 圖4.1-11 不同的Pt置換時間反應下之表面型態 58 圖4.1-12 Pt置換反應120min下之EPMA-mapping圖 58 圖4.1-13 Ni/PI電極經標準接附測試前後之表面差異 59 圖4.1-14 百格刀附著力測試之樣品製備圖 60 圖4.1-15 Ni/PI電極經標準接附測試前後之表面差異 60 圖4.1-16 Ni/PI電極經電解液浸泡測試之重量變化 61 圖4.1-17 不同Pt對電極之表面型態 63 圖4.1-18 不同白金對電極所組裝DSSC之J-V曲線 64 圖4.1-19 不同白金對電極之CV曲線 64 圖4.2-1 奈米金屬氧化物經450oC、1hr熱處理前後之晶粒結構與XRD分析 66 圖4.2-2 奈米金屬氧化物經95oC H2O2、1hr氧化處理之晶粒結構與XRD分析 67 圖4.2-3 ITO玻璃經TiCl4前處理前後之表面型態 67 圖4.2-4 電泳共鍍ZnO/TiO2之表面與橫截面照片 68 圖4.2-5 比較EPD ZnO光電極有無經過熱壓步驟之表面結構 69 圖4.2-6 各經EPD所製光電極之表面和橫截面結構 70 圖4.2-7 各經EPD所製光電極之Nyquist plot 71 圖4.3-1 SA-TiO2之(a) XRD晶格分析、(b) TEM晶粒分析 73 圖4.3-2 有無覆蓋SA-TiO2的FTO之穿透度曲線 73 圖4.3-3 AFM表面型態(morphology)分析 74 圖4.3-4 AFM表面相型態(phase)分析 75 圖4.3-5 各試片之橫截面SEM照片 75 圖4.3-6 有無覆蓋SA-TiO2之DSSC的I-V曲線 76 圖4.3-7 有無覆蓋SA-TiO2之IPCE曲線 78 圖4.3-8 FTO有無覆蓋SA-TiO2之Nyquist plot 78 圖4.3-9 FTO有無覆蓋SA-TiO2之等效電路圖 79 圖4.4-1 ZnO與Ta2O5-ZnO作為CBL之XRD分析結果 80 圖4.4-2 各塗層材料之AFM與粗糙度分析結果 81 圖4.4-3 以ZnO作為CBL的PSC有無添加PEIE之I-V曲線 84 圖4.4-4 電極表面添加PEIE層後之work function降低示意圖 84 圖4.4-5 以ZnO作為CBL電極時有無添加PEIE層之光穿透度曲線 85 圖4.4-6 BHJ層(P3HT:PC61BM)之吸收光譜曲線 85   表目錄 表2.3-1 高溫軟板光電極基材之DSSC光電性質整理 11 表2.3 2 塑膠軟板光電極基材之DSSC光電性質整理 12 表2.3 3 以Pt作為對電極材料之DSSC光電性質整理 19 表2.3 4 以Pt複合物或其它物質作為對電極材料之DSSC光電性質整理 21 表2.5-1 不同金屬氧化物之性質比較表 30 表3.1-1 各鍍鎳步驟之鍍液配方 33 表3.1-2 燒結溫度/時間參數 34 表3.1-3 染料配方及浸泡參數 34 表3.1-4 電解液配方 34 表3.2-1 EPD溶液配方及實驗參數 38 表3.4-1 PSC各層之溶質/溶劑配方 44 表3.4-2 PSC各層之旋塗與燒結參數 45 表4.1-1 初步測試之Pt seed/PI對電極之DSSC電性結果 49 表4.1-2 經高溫處理之nano-Pt/seed layer/PI對電極之DSSC電性結果 51 表4.1-3 各置換時間下之Pt負載量 59 表4.1-4 不同置換時間之對電極所組裝DSSC的光電效能性質表 62 表4.1-5 不同白金對電極所組裝DSSC的光電效能及內部界面電阻之數據表 62 表4.2-1 各經EPD製備之光電極所組裝DSSC之光電效能數據 71 表4.2-2 各經EPD製備之光電極所組裝DSSC之電化學分析數據 71 表4.3-1 有無覆蓋SA-TiO2之小面積電池DSSC光電效能數據 77 表4.3-2 有無覆蓋SA-TiO2之大面積電池DSSC光電效能數據 77 表4.3-3 FTO有無覆蓋SA-TiO2之DSSC電化學阻抗分析數據 79 表4.4-1 不同厚度之ZnO與Ta2O5-ZnO作為CBL之PSC的光電效能表現 81 表4.4-2 不同濃度Nb2O5作為CBL之inverted PSC的光電效能表現 82 表4.4-3 以Nb2O5作為CBL的表面修飾層時之inverted PSC的光電效能表現 83 表4.4-4 添加各濃度及厚度PEIE表面修飾層時之inverted PSC的光電效能表現 84 表4.4-5 各CBL電極有無添加PEIE表面修飾層之inverted PSC的光電效能表現 8

Effects of annealing conditions on the properties of TiO2/ITO-based photoanode and the photovoltaic performance of dye-sensitized solar cells

Photovoltaic performance of dye-sensitized solar cell (DSSC) is enhanced by a two-step annealing process of the photoanode. The 1st-step of annealing is performed in oxygen at 450 °C for 30 min which effectively removes the residual organics originated from the TiO2 precursor pastes. This enhances the dye adsorption on the TiO2 nanoparticles and raises the short-circuit current density (JSC). The 2nd-step of annealing is performed in nitrogen at 450 °C for 10 min which removes extra oxygen atoms resulted from the incorporation of oxygen atoms into the tin-doped indium oxide (ITO) film during the 1st-step of annealing. This reduces the sheet resistance of ITO and thereby enhances the fill factor (FF). With the enhanced JSC of 15.9mAcm−2 and FF of 0.65, the AM1.5 solar to electric conversion efficiency (η) of DSSC reaches 6.7% which is better than that based on the conventional one-step air annealing (η = 5.53%, JSC = 14.08 mA cm−2, FF = 0.6)

A Compact Nano-TiO2 Underlayer forEfficient Dye-Sensitized Solar Cell

A compact nano-TiO2 underlayer is formed on atitanium (Ti) foil through a two-step H2O2 + NaOH soakingpretreatment. This underlayer effectively suppresses thecharge recombination reaction on the photoanode side, whichis attributed to efficient electron transfer due to good adhesionbetween Ti and nano-TiO2. It also enhances the electricalcontact with screen-printed TiO2 mesoporous film due to surfacenanostructure. Both fill factor and short-circuit current densityare improved, and accordingly the power conversion efficiencyof dye-sensitized solar cell is enhanced by 22%

An efficient titanium-based photoanode fordye-sensitized solar cell under back-side illumination

Pretreatment of H2O2 is performed on titanium (Ti) foil as an efficient photoanode substrate for dye-sensitized solar cell(DSSC). The H2O2-treated Ti shows high surface area because of the formation of networked TiO2 nanosheets, whichenhances electrical contact between screen-printed TiO2 nanoparticles and Ti foil. Electron transfer on the photoanode isimproved, as identified by reduced charge transfer resistance and improved electron transport properties. Compared withDSSC based on non-treated Ti photoanode, DSSC with this H2O2-treated Ti photoanode exhibits remarkable increasesin short-circuit current density (from 8.55 to 14.38 mA/cm2) and energy conversion efficiency (from 4.68 to 7.10%) underAM1.5 back-side illumination. Copyright © 2011 John Wiley & Sons, Ltd

Chemical Deposition of Ni/Pt Bi-Layer on Polyimide Film as Flexible Counterelectrodes for Dye-Sensitized Solar Cells

A metalized plastic substrate made of a polyimide film coated with a Ni/Pt bi-layer is prepared as counterelectrode for dye-sensitized solar cell (DSSC). Surface metallization of Ni/Pt on polyimide is carried out via a chemical process, where top Pt acts as the catalyst and bottom Ni is the conduction/light-reflection layer. This counterelectrode possesses superior sheet resistance (0.173 X/h) and charge transfer resistance (0.38 X cm2). The DSSC based on this metalized polyimide counterelectrode exhibits an enhanced fill factor (0.7), and accordingly its energy conversion efficiency achieves 7.12%, which is better than those assembled with other platinized counterelectrodes prepared by sputtering

Nanotwinning-assisted structurally stable copper for fine-pitch redistribution layer in 2.5D/3D IC packaging

The redistribution layer (RDL) is crucial for fanning out circuits and for 2.5D/3D IC packaging. As device density increases, RDL CD/pitch must shrink. During RDL circuit fabrication, the etching process is necessary to remove the exposed sputtered Cu seed layer and Ti barrier layer. Unfortunately, this process unavoidably etches and roughens the Cu surface of the RDL. As the post-plating resting time (q-time) increases, the Cu surface oxidizes, resulting in even worse surface roughness after etching. This roughness causes contact resistance and electromigration issues when the RDL linewidth shrinks. This paper presents a composite Cu structure that combines fine grains and nanotwins, which is structurally stable and can effectively resist surface damage even after extended periods, offering a promising solution for achieving finer RDL in advanced packaging technologies with a longer electromigration lifetime than regular coarse-grain lines

Pre-Treatment with Ten-Minute Carbon Dioxide Inhalation Prevents Lipopolysaccharide-Induced Lung Injury in Mice via Down-Regulation of Toll-Like Receptor 4 Expression

Various animal studies have shown beneficial effects of hypercapnia in lung injury. However, in patients with acute respiratory distress syndrome (ARDS), there is controversial information regarding the effect of hypercapnia on outcomes. The duration of carbon dioxide inhalation may be the key to the protective effect of hypercapnia. We investigated the effect of pre-treatment with inhaled carbon dioxide on lipopolysaccharide (LPS)-induced lung injury in mice. C57BL/6 mice were randomly divided into a control group or an LPS group. Each LPS group received intratracheal LPS (2 mg/kg); the LPS groups were exposed to hypercapnia (5% carbon dioxide) for 10 min or 60 min before LPS. Bronchoalveolar lavage fluid (BALF) and lung tissues were collected to evaluate the degree of lung injury. LPS significantly increased the ratio of lung weight to body weight; concentrations of BALF protein, tumor necrosis factor-α, and CXCL2; protein carbonyls; neutrophil infiltration; and lung injury score. LPS induced the degradation of the inhibitor of nuclear factor-κB-α (IκB-α) and nuclear translocation of NF-κB. LPS increased the surface protein expression of toll-like receptor 4 (TLR4). Pre-treatment with inhaled carbon dioxide for 10 min, but not for 60 min, inhibited LPS-induced pulmonary edema, inflammation, oxidative stress, lung injury, and TLR4 surface expression, and, accordingly, reduced NF-κB signaling. In summary, our data demonstrated that pre-treatment with 10-min carbon dioxide inhalation can ameliorate LPS-induced lung injury. The protective effect may be associated with down-regulation of the surface expression of TLR4 in the lungs