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

Abstract Single crystals of lead-free halide double perovskite Cs₂AgBiBr₆ sensor material manifest a remarkable potential for application in radiation detection and imaging. In this study, the purity and crystallinity of solution-grown Cs₂AgBiBr₆ single crystals with cubic Fm$$\overline{3}$$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 (10⁶–10⁹ Ωcm) was obtained from the I-V measurements compared to the 1.55 × 10⁹–6.65 × 10¹⁰ 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-Cs₂AgBiBr₆ (1.90–4.82 cm²V⁻¹ s⁻¹) and the Ag-Cs₂AgBiBr₆ (0.58–4.54 cm²V⁻¹ s⁻¹) including the density of trap states (10⁹–10¹⁰ cm⁻³) are comparable. Similar values of 1.89 cm²V⁻¹ s⁻¹ and 2.36 cm²V⁻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 Cs₂AgBiBr₆ samples synthesized in this study satisfy requirements for radiation sensors. Graphical abstract