使用可量產配方及快速製程於大氣下製備高效率大面積鈣鈦礦太陽能電池

Abstract

由於鈣鈦礦太陽能電池能以低成本的溶液製程製備，對於量產商業化有顯著的潛力。目前高效率的鈣鈦礦太陽能電池中，製備方法通常為旋轉塗佈法且多為小面積的電池。刮刀塗佈法為一項非常簡易可以製備大面積均勻薄膜的技術，目前刮刀塗佈法製備之鈣鈦礦電池中，仍使用有致癌性的二甲基甲醯胺(DMF)來配置鈣鈦礦前驅物溶液並於氮氣下沉積薄膜，這些不利於工業上的安全及成本考量。本研究利用Hansen溶解度常數(Hansen solubility parameters)及施體數(donor number)選擇適合鈣鈦礦前驅物的溶劑，且能以無毒的γ-丁內酯(GBL)及二甲基亞碸(DMSO)的混合溶劑配置鈣鈦礦前驅物溶液，於大氣下以刮刀塗佈法製備鈣鈦礦薄膜，將此薄膜製成高效率的鈣鈦礦太陽能電池，透過改變溶劑比例及加入添加劑來控制薄膜的表面形貌、界面及結晶度。此結果能以適合量產的塗佈技術製備且解決溶劑毒性問題。 為了製備更大面積的薄膜，使用狹縫式塗佈法並結合近紅外光加熱技術在大氣中快速製備鈣鈦礦太陽能電池。在鈣鈦礦前驅物溶液中加入正丁醇，同時降低溶液的表面張力及增加近紅外光波長的吸收度，因此加速溶液的揮發速度與成膜速度，並使鈣鈦礦快速結晶，不需要額外的熱處理，能在18秒內製備出12公分×12公分的高品質且均勻雙陽離子鈣鈦礦薄膜，此薄膜製備成電池，最高效率能達到15.53%。此外，展示除了電極外其他層皆以全狹縫式塗佈法於大氣下製備鈣鈦礦太陽能電池的四層均勻薄膜，此製程及加熱技術結合能有效減少製程時間及跳過熱處理步驟，對於量產製程有更進一步的發展。 為了製備大面積太陽能電池，模組化的圖案所建立的內部串聯結構則極為重要，我們透過控制活性區寬度來減少來自雷射切割熱殘留所造成的電阻損耗，並能製備出面積為1平方公分及5平方公分電池，其效率表現分別能保有小面積電池效率的98%及88%，能有效減少面積放大造成的效率損耗，對於大面積模組製備有明顯的幫助。進而運用於狹縫式塗佈法沉積每一層，利用雙面加熱技術來減少溫度梯度的產生及薄膜收縮的現象，得到全覆蓋的均勻鈣鈦礦薄膜。最終結合以上結果，我們能製備出46平方公分之大面積全狹縫式塗佈製備之鈣鈦礦模組，最高效率約為7.19%，此研究成果展示出鈣鈦礦太陽能電池發展的高度商業化潛力，進而加速未來鈣鈦礦產業的發展。

Low-cost and solution-processed perovskite solar cells have shown great potential in scaling-up for mass production. Compared with the spin-coating process of fabricating devices with the small area, the scalable process is a facile technique of preparing large-area films. High-efficiency perovskite solar cells have been reported using scalable coating, but they were fabricated using the toxic solvent of N,N-dimethylformide (DMF) in nitrogen. Here, we use the Hansen solubility parameters and donor number to select the suitable solvents to prepare of the perovskite precursor solution. Then, highly efficient blade-coated perovskite solar cells were prepared using a green solvent mixture of gamma-butyrolactone (GBL) and dimethyl sulfoxide (DMSO) in an ambient environment. By carefully controlling the interface, morphology, and crystalline of perovskite film through composition variations and additive. The findings in this work resolve scalability and solvent toxicity; thus, perovskite solar cells’ mass production becomes feasible. Furthermore, we use the slot-die coating is combined with near-infrared irradiation heating to manufacture perovskite solar cells in the air quickly. The solvent composition of the perovskite precursor solution is tuned by adding n-butanol of low boiling point and low surface tension to increase fthe near-infrared energy absorption and facilitate the evaporation of solvent system and film formation. The high-quality uniform perovskite film can be prepared within 18s. The highest PCE of dual-cation PSCs prepared using this uniform film can be achieved by 15.53%. Moreover, the all slot-die coating process is demonstrated to prepare four layers of uniform film overlay on top of each other for the devices except electrode in ambient air. This simple process can significantly reduce the cost, time and bypass post-annealing to fabricate high-efficiency large-area perovskite solar cells in ambient air. We tune the sub-cell width to improve the resistance loss from the heat accumulation of laser ablation. Finally, we fabricate modules with two kinds of the active area of 5 cm2 and 1 cm2. The PCE of modules can be maintained as 98% and 88%, respectively, compared with that of 0.09 cm2 cell. The results are promising to fabricate the large-area module. For large-area coating on scribed FTO substrate, we apply a hot-plate-assisting of 60oC to reduce the film shrinkage during NIR heating. The full coverage of perovskite film can be obtained. Finally, the large-area all slot-die coated perovskite module is demonstrated with an active area of 46 cm2. The highest PCE of a large-area module can be achieved by 7.19%. These results can promote the development of perovskite solar cells and achieve commercialization potential soon.