Double perovskite Cs2AgBiBr6 radiation sensor: synthesis and characterization of single crystals

Abstract

Single crystals of lead-free halide double perovskite Cs(2)AgBiBr(6) sensor material manifest a remarkable potential for application in radiation detection and imaging. In this study, the purity and crystallinity of solution-grown Cs(2)AgBiBr(6) single crystals with cubic Fm 3m symmetry have been corroborated by powder XRD measurements, while the single crystal XRD patterns reveal the dominant {111} lattice planes parallel to the sample surfaces. A wider range of lower resistivity values (10^6-10^9 Ωcm) was obtained from the I-V measurements compared to the 1.55 x 10^9-6.65 x 10^10 Ωcm values from the van der Pauw method, which is typically higher for the Ag than for the carbon paint electrodes. Charge-carrier mobility values estimated from the SCLC method for the carbon paint-Cs(2)AgBiBr(6) (1.90-4.82 cm^2 V^(-1) s^(-1)) and the Ag-Cs(2)AgBiBr(6) (0.58-4.54 cm^2 V^(-1) s^(-1)) including the density of trap states (10^9-10^10 cm^(-3)) are comparable. Similar values of 1.89 cm^2 V^(-1) s^(-1) and 2.36 cm^2 V^(-1) s^(-1) are derived from the Hall effect measurements for a sample with carbon and Ag electrodes, respectively. The key electrical parameters including the X-ray photoresponse measurements indicate that the Cs(2)AgBiBr(6) samples synthesized in this study satisfy requirements for radiation sensors.