受全球暖化與氣候變遷的影響，2015年聯合國通過巴黎協議，以推展展綠色能源，從而減少CO2之排放量。近年，鈣鈦礦太陽能電池(perovskite solar cells (PSCs))發展迅速，尤其具高效率與低製備成本的特點，使其成為太陽能研發焦點。本研究重點是製備低成本、環境友善、製程簡單、及可撓曲之PSCs，主要研究工作包括：(I)研究低溫製程之TiO2緻密(c-TiO2)層，作為PSCs之電子傳輸層；(II)在烷類非極性溶劑製備鈣鈦礦層，以克服水氣的影響；(III)回收廢棄PSCs之PbI2及FTO導電玻璃；(IV)以c-TiO2層與碳電極製備可撓曲式PSCs，提升應用性。
SEM顯示以0.2 M TiCl4製備之c-TiO2層具較高覆蓋率及厚度(28 nm)，由光致螢光光譜(PL)分析得知厚度28 nm的c-TiO2層有較低的螢光強度，因而降低光電子、電洞再結合速率。控制TiO2與乙醇的稀釋比例(2/6)，可獲TO2孔洞層(p-TO2)較有利厚度478 nm，使具較佳光吸收性及光伏表現。PSCs製備中鈣鈦礦層生成過程對水氣相當敏感，可能影響鈣鈦礦層的結晶性與覆蓋率，因此，另以烷類非極性溶劑製備鈣鈦礦層，達到與水氣隔絕的效果。SEM指出在庚烷中形成的鈣鈦礦層具較高覆蓋性。XRD與PL分析結果顯示在庚烷中製備之鈣鈦礦層有較佳的結晶性與較低之電子、電洞再結合速率。以此方法可將PSCs之光電轉化效率(PCE)從2.0%提升至6.1%，進一步改善烷類非極性溶劑中鈣鈦礦前驅物濃度與加熱溫度，可將PCE提升至8.75%。此PSCs之新穎分層製備方法，使之易於在一般環境下塗佈於向陽表面(例如：屋頂、牆或窗)，增加廣泛應用性。另開發以水萃取分離回收廢棄PSCs中之PbI2及FTO導電玻璃之方法，減少鉛之環境負面衝擊；更以c-TO2層與碳電極製備可撓曲式PSCs，增加其應用性。

Mainly due to the negative impact from global warming and climate change, the United Nations passed the Paris Agreement that focused on reducing CO2 emissions by increasing green energy utilization. Recently, research and development related to perovskite solar cells (PSCs) with the advantages of high power conversion efficiency (PCE) and low manufacturing cost have been growing very rapidly. Thus in the present work, a feasibility study for preparation of low-cost, simple process, and environmental-friendly flexible perovskite solar cells was carried out. The major research work include: (1) Preparation of better TiO2 electron transport layer for PSCs; (2) A feasibility study for preparation of moisture-resisted perovskite layers in PSCs; (3) Recovery of PbI2 and FTO conducting glass from spent PSCs; and (4) Preparation of flexible PSCs.
Experimentally, a desired thickness (25 nm) for the c-TiO2 layer can be obtained when 0.2 M of TiCl4 were used, and the well dispersed TiO2 layer on FTO with a relatively low luminescence intensity are observed. The p-TiO2 layer was also prepared by spin-coating with the TiO2 paste at the preferred TiO2/ethanol (w/w) ratio of 2/6. More perovskite can be adsorbed on the p-TiO2 layer for a better harvesting light. The less perturbed (by moisture) perovskite layer having a better crystallinity and low photoluminescence intensity, possibly due to the fact of the reduced electron-hole recombination rate during illumination, accordingly, gives a rise to its PSC performance, and the PCE can be increased to 6.1% (from 2.0%). More effectively, the PSC comprised of the carbon/CH3NH3PbI3/porous TiO2/compact TiO2/FTO layers has a high PCE up to 8.75% as the perovskite (CH3NH3PbI3) layer was formed by the way of the new procedure especially in the presence of humidity. With this approach, PSCs can be installed by means of layer-by-layer coating onto any sunlight accessible surfaces such as outdoor windows, walls, and roofs. In addition, to reduce the environmental negative impacts from the lead toxic metal, a method has been developed to recover PbI2 from the spent PSC. Methods for preparation of flexible PSCs using the c-TiO2 layer and carbon electrode were also developed for wide applications.

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