FAPbI₃ Perovskite Films Prepared by Solvent Self-Volatilization for Photovoltaic Applications

Qiqi Zhang, Jackson State University
Guorong Ma, University of Southern Mississippi
Kevin A. Green, University of Southern Mississippi
Kristine Gollinger, Jackson State University
Jaiden Moore, Jackson State University
Teresa Demeritte, Jackson State University
Paresh Chandra Ray, Jackson State University
Glake Alton Hill Jr., Jackson State University
Xiaodan Gu, University of Southern Mississippi
Sarah E. Morgan, University of Southern Mississippi
Manliang Feng, Tougaloo College
Santanu Banerjee, Tougaloo College
Qilin Dai, Tougaloo College

Abstract

Developing a simple method to synthesize the perovskite layer without the antisolvent technique can facilitate the industrial production of perovskite solar cells (PSCs). Limited progress has been made for the antisolvent-free method on formamidinium lead triiodide perovskite layers because of the phase stability issue. Here, we use N-methyl pyrrolidone (NMP) as an additive to inhibit the nonperovskite phase of FAPbI₃ to fabricate the formamidinium iodide (FAI)–PbI₂–NMP intermediate phase via the self-volatilization of volatile solvent 2-methoxyethanol instead of the traditional antisolvent method. The high-quality pure α phase of FAPbI₃ films is obtained by phase transition via annealing. The photovoltaic properties of the perovskite films affected by different NMP amounts are studied. The corresponding PSCs show a PCE of 20.1% compared to 15.6% for the PSCs fabricated with the classical antisolvent technique. The unencapsulated devices exhibit ∼75% efficiency of their initial PCE values after 35 days of storage. This method can be used in the scalable production of PSCs because of high reproducibility and easy operation.