Simple and Solvent-Free Procedure for Fabricating Ag/Bi-based Halide Double Perovskite Polycrystalline Wafers and Investigating Their Photodetector Properties

Abstract

Herein, a solvent-free and simple solid-state method was used to synthesize Cs2AgBiBr6 wafers. Cs2AgBiBr6 particles were successfully synthesized in two steps, namely grinding and annealing. Phase-pure Cs2AgBiBr6 was produced in a very short time, such as 4 h, by stepwise heat treatment at 205 degrees C for 2 h and 250 degrees C for 2 h after grinding bromide powders for 20 min in an agate mortar. Another grinding step for 20 min, following the phasepure synthesis of Cs2AgBiBr6, facilitated the formation of larger perovskite grains through sintering at 350 degrees C. Increasing the sintering time from 4 h to 20 h also contributed to the formation of larger and more compact perovskite grains. This study demonstrated that the formation of larger and more compact grains through sintering at 350 degrees C for 20 h contributes to better detectivity and responsivity values for solvent-free produced Cs2AgBiBr6 wafers. Additionally, the structural strength of the material was examined through hardness tests using the nanoindentation method, resulting in a value of 0.0923 MPa. The simple and solvent-free method employed in this study may create opportunities to fabricate emerging double perovskites for detector applications.