Improved photovoltaic properties of ((CH3NH3)1−xCsx)3Bi2I9: (x = 0−1.0) hybrid perovskite solar cells via a hot immersion method

• Published in: AIMS Materials Science
• Main Author: Achoi M.F.; Kato S.; Kishi N.; Soga T.
• Format: Article
• Language: English
• Published: AIMS Press 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85201157875&doi=10.3934%2fMATERSCI.2024031&partnerID=40&md5=41b67783101981cc0eef7ad80b077154

To date, the lead-free perovskite has shown remarkable progress in solar cell development owing to its outstanding properties. Here, we report on the structural, optical, and photovoltaic properties of methylammonium bismuth iodide ((CH3NH3)3Bi2I9, MBI) and cesium bismuth iodide (Cs3Bi2I9, CBI) hybrid perovskite solar cells (HPeSCs) fabricated using the hot immersion method (HIM) with changing the composition x, ((CH3NH3)1−xCsx)3Bi2I9; from x = 0 to x= 1.0. The compact MBI and CBI films were successfully fabricated on FTO glass substrates at x = 0 and x = 1, respectively. On the other hand, the CBI/MBI mixed structure with a rough surface was obtained in the range from x = 0.2 to x = 0.8. An incorporation of CBI in MBI showed improvement, especially in optical properties, indicating that the absorption region was extended toward a longer wavelength region with increasing x. Interestingly, the open-circuit voltage of the hybrid cell was higher than that of the MBI or CBI cell, whereas the short-circuit current was lower than that of the MBI or CBI cell. This work provides alternative ways to fabricate lead-free PeSCs using a simple and low-cost method in the future. © 2024 the Author(s)