Hexagonal Lead-Free Cs<sub>2</sub>AgBiI<sub>6</sub> Perovskite Nanocrystals: A Promising Material for Solar Cell Application
Yueli Liu, Yifan Huang, Zifan Yang, Yipeng Li, Jie Xu, Huizhong Li, Wen Chen, Keqiang Chen
Abstract
Lead halide perovskite (LHP) nanocrystals (NCs) have extensive applications in optoelectronics. However, their high toxicity and low stability inhibit their commercialization. Herein, lead-free Cs 2 AgBiI 6 NCs with a hexagonal phase are synthesized using a hot-injection process, which exhibit a band gap of 2.29 eV, a high absorption coefficient (∼2.8 × 10 5 cm –1 ), and a symmetric and narrow photoluminescence peak (full width at half-maximum = 10 nm). In addition, the hexagonal Cs 2 AgBiI 6 NC films exhibit high resistance to heat, humidity, and illumination in air. Solar cells based on hexagonal Cs 2 AgBiI 6 NCs are fabricated for the first time, achieving a power conversion efficiency (PCE) of 0.076%, which confirms its promising potential for photovoltaic applications.