Methylammonium Bromide Assisted Crystallization for Enhanced Lead?Free Double Perovskite Photovoltaic Performance

Cs2AgBiBr6, has recently gained wide attention as a possible alternative to lead-halide perovskites, considering the nontoxicity and improved stability. However, this double perovskite suffers from defects, especially deep electron traps, severely hampering photovoltaic performance. This work reports simple method control crystallization by adding volatile salts into precursor solution. X-ray diffraction patterns reveal that organic cation with suitable radius (such methylammonium, MA+) is introduced lattice, forming an organic/inorganic mixed intermediate phase. The salt thereafter fully evaporated during high temperature annealing, all-inorganic obtained dense surface less pin-holes. From optical electrical characterization, it concluded Cs2AgBiBr6 film exhibits quality, higher light absorptance emission. Reduced trap density longer carrier lifetime are also observed. beneficial for efficient collection suppressed defect-assisted recombination. With strategy, power conversion efficiency (PCE) of 2.53% achieved champion Cs2AgBiBr6-based solar cell device, which significantly compared device 1.43% PCE. therefore helpful further improvement inorganic lead-free materials optoelectronic applications.