Analysis of photodetector and mechanical properties of halogen perovskite compounds produced by solid state sintering method

Recent studies have shown that halide perovskite compounds could replace commercially used detector materials due to their superior photodetector performance. Halide perovskite compounds can be divided into two main groups, organic-inorganic and inorganic. Although promising detectors have been produced using organic-inorganic perovskites, these compounds are known to be susceptible to external factors such as humidity, oxygen, heat, light, and electric fields, making them unstable. Therefore, detectors produced using inorganic perovskite compounds are more prominent. Among the inorganic perovskites, studies have focused particularly on Cs2AgBiBr6, also known as double perovskite. Most studies focus on the production of these materials as single crystals. Production of these materials in this way takes days. Moreover, the shape, size, and thickness of the samples cannot be controlled during the synthesis. Other disadvantages of these methods are using acidic solutions or high temperatures during the synthesis. On the other hand, these materials with a high potential for commercialization can be fabricated by solid-state sintering with desired shape and thickness in a shorter time without using any solvent. In this study, polycrystalline, cubic structure double perovskite Cs2AgBiBr6 was produced by solid state sintering method in pellet form using different approaches. In order to determine the photodetector properties (responsivity (R) and detectivity (D*)) of the produced samples in pellet form, current-voltage (I-V) and current-time (I-t) measurements were performed in the dark and under 532 nm laser light. The best photodetector performance was obtained after the pure synthesized Cs2AgBiBr6 compound was again grinded, pressed and sintered at 350 °C for 20 hours after grinding and annealing steps. Then, the mechanical properties of this sample were analyzed by nanoindentation method to understand the adequacy of the structural strength of the material. With the nanoindentation method, the values of hardness (H) and modulus of elasticity (E) values, which are the basic mechanical properties of the material, were obtained using the Oliver Pharr method. The values obtained as a result of the experiments were compared with the values obtained from other perovskite materials and single crystal Cs2AgBiBr6 samples in the literature.