| Title |
Study on A-Site Compositional Mixing for the Shear Coating Process of FA-Based Lead Halide Perovskites |
| Authors |
김한솔(Hansol Kim); 구혜원(Hyewon Gu); 송민주(Minju Song); 정중희(Choong-heui Chung); 오용준(Yong-jun Oh); 송창은(Chang Eun Song); 홍기하(Ki-ha Hong) |
| DOI |
https://doi.org/10.3365/KJMM.2021.59.5.321 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
perovskite; shear-coating; solar-cell; large-area; FAPbI3 |
| Abstract |
Halide perovskite solar cells have been attracting tremendous attention as next-generation solar cell materials because of their excellent optical and electrical properties. Formamidinium lead tri-iodide (FAPbI3) exhibits the narrowest band gap among lead iodide perovskites and shows excellent thermal and chemical stability, also. However, the large-area coating of FAPbI3 needed for commercialization has not been successful because of the instability of the black phase of FAPbI3 at ambient temperature. This study presents a compositional engineering direction to control the polymorph of the FAPbI3 thin film for the shear coating processes, without halide mixing. By adopting a hot substrate above 100 ℃, our shear coating process can produce the black phase FA-based halide perovskites without halide mixing. We carefully investigate the Cs- FA and MA-FA mixed lead iodide perovskites’ phase stability by combining the study with thin-film fabrication and ab initio calculations. Cs-FA mixing shows promising behaviors for stabilizing α-FAPbI3 (black phase) compared with MA-FA. Stable FA-rich perovskite films cannot be achieved via shear coating processes with MA-FA mixing. Ab initio calculations revealed that Cs-FA mixing is excellent for inhibiting phase decomposition and water incorporation. This study is the first report that FA-based halide perovskite thin films can be made with the shear coating process without MA-Br mixing. We reveal the origin of the stable film formation with Cs-FA mixing, and present future research directions for fabricating FA-based perovskite thin films using shear coating.(Received January 14, 2021; Accepted March 4, 2021) |