Post‐Deposition Vapor Annealing Enables Fabrication of 1 cm2 Lead‐Free Perovskite Solar Cells

• DOI: 10.1002/solr.201970114
• Publication Date: 2019-12-06T09:27:15Z
• Authors: Towhid H. Chowdhury; Md. Emrul Kayesh; Jae-Joon Lee; Yoshitaka Matsushita; Said Kazaoui; Ashraful Islam
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Sn‐based perovskite solar cells (PSCs) are promising alternatives to replacing toxic Pb‐based PSCs, which have shown a rapid rise in photovoltaic applications in the past 1 year. However, the reported Sn‐based PSCs are often fabricated with a small aperture area (typically 0.02–0.1 cm2) because forming homogeneous pinhole‐free continuous films over a large surface area is still challenging. Herein, a post‐deposition vapor annealing (PDVA) process assisted by methylammonium chloride vapor is presented that enables the fabrication of stable, homogeneous pinhole‐free FASnI3 perovskite absorber films with low crystal defects and low surface recombination over a relatively large area up to 1.02 cm2. Inverted planar solar cells fabricated with a 1.02 cm2 aperture area show a maximum power conversion efficiency of 6.33% with high reproducibility and stability. The shelf‐lifetime stability test shows that the PSCs retain 90% of their performance for more than 1000 h when stored in a N2‐filled glove box and under dark conditions. The preliminary light‐soaking stability tests under continuous illumination and maximum power‐tracking conditions are relatively promising. This study marks an important step toward the up scaling of Sn‐based PSCs.