Double perovskite Cs 2 AgBiBr 6 radiation sensor: synthesis and characterization of single crystals

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 3 m 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 × 10 9 –6.65 × 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. Graphical abstract