Porous Lead Iodide Layer Promotes Organic Amine Salt Diffusion to Achieve High Performance p‐i‐n Flexible Perovskite Solar Cells

• Published in: Advanced energy materials 2023-09, Vol.13 (36), p.n/a
• Main Authors: Sun, Qing, Duan, Shaocong, Liu, Gang, Meng, Xiangxin, Hu, Die, Deng, Jianguo, Shen, Bo, Kang, Bonan, Silva, S. Ravi P.
• Format: Article
• Language: English
• Subjects: Additives; Bend radius; Crystal defects; dense perovskite films; Diffusion layers; Energy conversion efficiency; flat perovskite films; flexible perovskite solar cells; fluffy porous lead iodide; high efficiency and stability; Perovskites; Photovoltaic cells; Pinhole defects; Pinholes; quaternary ammonium halide additives; Quaternary ammonium halides; Relative humidity; Solar cells; Stability
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202301259

Flexible perovskite solar cells (FPSCs) are attracting widespread research and attention for their benefits as the next‐generation wearable electronic products. However, there are still many challenges in the quest to achieve dense, pinhole‐free, high crystal quality, low defect, and stable perovskite films, which limit further improvement in the efficiency and stability of FPSCs. Herein, a novel technique for the incorporation of quaternary ammonium halide (QAH) additives to prepare fluffy porous lead iodide layers by using a two‐step sequential deposition method, is reported. Benefiting from the good diffusion of organic amine salts on porous PbI2 layers, flat and dense perovskite films are produced with large particle sizes, few defects, and high crystal quality. Finally, the champion rigid and flexible p‐i‐n PSCs with the 2‐(acetyloxy)‐N,N,N‐trimethylethanium chloride (AtaCl) additive achieves exciting power conversion efficiencies (PCE) of 23.40% and 21.10%, respectively. The device with the AtaCl additive retains over 90% of its original PCE under ambient conditions (40 ± 5% relative humidity (RH)) over 1000 h of aging without encapsulation. In addition, the flexible device with the AtaCl additive shows excellent stability under mechanical bending conditions, retaining ≈85% of its original PCE after 10 000 cycles (bending radius = 5 mm). Highly efficient and stable, rigid and flexible p‐i‐n perovskite solar cells are developed by incorporating a 2‐(acetyloxy)‐N,N,N‐trimethylethanium chloride additive into the lead iodide precursor solution to prepare a porous PbI2 layer. The good diffusion of the organic ammonium salt results in flat and dense perovskite film with large particle size, which achieves high power conversion efficienciesPCE of 23.40% (rigid) and 21.10% (flexible) with excellent ambient and mechanical stability.