Formamidinium post‐dripping on methylammonium lead iodide to achieve stable and efficient perovskite solar cells

• Published in: International journal of energy research Vol. 46; no. 4; pp. 5306 - 5314
• Main Authors: Syed, Jawad Ali Shah, Khan, Danish, Ahmad, Waseem, Soomro, Ghulam Sarwar, Dar, Afzal Ahmed
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Inc 25-03-2022; Hindawi Limited
• Subjects: Carrier lifetime; Cations; Crystallization; Energy conversion efficiency; FAI‐treatment; Grain size; Humidity; Iodides; large‐grain size perovskite films; mixed‐cations; Particle size; Perovskite solar cells; Perovskites; Photovoltaic cells; Solar cells; Thermal stability
• ISSN: 0363-907X; 1099-114X
• DOI: 10.1002/er.7496

Summary
Formamidinium iodide (FAI) based perovskite solar cells (PSCs) have now been established as effective PSCs than methylammonium lead iodide perovskite for several years due to their optimal bandgap and high thermal stability. However, the FAI‐based PSCs have humidity issues, due to which mixed cation perovskites are getting popular. MAI‐based PSCs have better stability against high humidity but low thermal stabilities. Herein, we prepared highly crystallized, efficient, and large‐grain size perovskite films via FAI post‐dripping process. In addition, the most promising structures FAI mixed MAPbI3 were explored as stable and effective active layers. The post‐dripping of FAI solution just after the MAPbI3 deposition provides a robust long‐distance diffusion, long carrier life, and enhanced grain sizes when compared to MAPbI3 PSCs. Based on the facile way of mixed cation perovskite preparation by post‐dripping, the power conversion efficiency (PCE) has risen from 15.24% to 17.52% in comparison with the pristine devices. This results in the best quality and large grain perovskite films which enhanced the PSCs' performance by reducing defect density and regulating the crystallization rate.
FAPbI3 is thermally stable perovskite and exhibits high Power conversion Efficiency than MAPbI3, but there is phase conversion issue in FAPbI3. Herein, the FA has been placed in MA PbI3 lattice and PCE and stability has been increased.