(C6H5NH3)BiI4: A Lead-Free Perovskite with >330 Days Humidity Stability for Optoelectronic Applications
A key challenge in eco-friendly optoelectronic materials field is to find highly stable and nontoxic perovskite material. Here, we report the optoelectronic properties and stability of (C6H5NH3)BiI4 perovskite material. Using an eco-friendly gas pump treatment technique, a dense and pinhole-free (C6H5NH3)BiI4 film was fabricated. Remarkably, a large-area (>20 cm2) Bi-based perovskite film was obtained, which is the largest Bi-based perovskite film ever reported. Besides, the (C6H5NH3)BiI4 perovskite exhibits good solubility in ethanol, which is a safe and eco-friendly solvent. Thermogravimetric analysis result shows the beginning of weight loss at ~184℃, suggesting excellent heat stability of this material. Most importantly, the (C6H5NH3)BiI4 film can tolerate continuous moisture exposure for 334 days in ambient air owing to the presence of a hydrophobic organic chain. To our best knowledge, this is the longest moisture stability test for lead-free perovskite materials so far. This work paves a way for realizing highly stable and nontoxic perovskite materials for potential optoelectronic applications.