Affiliation:
1. Department of Physics Savitribai Phule Pune University Pune 411 007 India
2. MIE-SPPU Institute of Higher Education Doha Qatar
3. Department of Materials Engineering Indian Institute of Science Bangaluru 560 012 India
4. Department of Applied Science and Humanities Pimpri Chinchwad College of Engineering, Nigdi Pune 411 004 India
Abstract
AbstractLead‐free ternary bismuth halide perovskites A3Bi2X9 have gained much attention as a solution for toxic and unstable lead halide perovskites due to their facile solution processability, high optical absorption coefficient, and high stability. However, their photovoltaic performance remains poor due to their wide bandgap (∼2 eV), and poor charge transport properties stem from their low‐dimensional crystal structure. To promote the 3D structure and reduce the bandgap of ternary Bi‐halide perovskites, we replace the alkali elements at the A‐site with the transition element Ag+ to obtain a new class of perovskite‐like materials named rudorffites AgaBibIa+3b. We investigated the photophysical properties of AgBiI4 by a combined theoretical and experimental approach. Our DFT‐PBE‐SOC predicted band gap for cubic defect spinel AgBiI4 is 2.01 eV, while that obtained for spin‐coated AgBiI4 film is 1.67 eV. Furthermore, the strong p‐p band edge transition leads to high optical absorption in this material. Finally, a photodetector device fabricated using AgBiI4 shows excellent photoresponsivity (183 μA/W) and detectivity (20.93×108 Jones) with a fast rise/decay time of 0.27 s/0.29 s. This newly explored semiconductor class can be a promising and stable choice for advanced optoelectronic devices.