CsPbBr and CsAgBiBr Composite Thick Films with Potential Photodetector Applications.

This paper investigates the optoelectronic properties of CsPbBr, a lead-based perovskite, and CsAgBiBr, a lead-free double perovskite, in composite thick films synthesized using mechanochemical and hot press methods, with poly(butyl methacrylate) as the matrix. Comprehensive characterization was conducted, including X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV-visible spectroscopy (UV-Vis), and photoluminescence (PL). Results indicate that the polymer matrix does not significantly impact the crystalline structure of the perovskites but has a direct impact on the grain size and surface area, enhancing the interfacial charge transfer of the composites. Optical characterization indicates minimal changes in bandgap energies across all different phases, with CsPbBr exhibiting higher photocurrent than CsAgBiBr. This is attributed to the CsPbBr superior charge carrier mobility. Both composites showed photoconductive behavior, with CsAgBiBr also demonstrating higher-energy (X-ray) photon detection. These findings highlight the potential of both materials for advanced photodetector applications, with CsAgBiBr offering an environmentally Pb-free alternative.