Polycrystalline Perovskite X-ray Detectors

Metal-halide perovskite materials have begun to attract much attention recently for their potential use in radiation detection applications. This interest is mainly due to their favourable semi-conductive properties, high electron density, ease of manufacture and relatively low cost compared to popular detector materials. In this paper we investigate inorganic caesium lead bromide (CsPbBr ₃ ). Polycrystalline powder samples were produced by solution growth and simple `sandwich' devices were fabricated. The powder was manually ground and then pressed to form pellets of a few mm thickness. Gold planar electrodes were deposited on the top and bottom perovskite surfaces by evaporation and were connected to an external circuit. We have made comparative measurements of the photoluminescence (PL), dark current and temporal radiation response. The PL measurements showed stable emissions centred at 525 nm for CsPbBr ₃ ' which is typical of these materials and within a useful range for this application. A CsPbBr ₃ device was exposed to X-rays and demonstrates a good increase in photocurrent over the dark current under both positive and negative bias with a sensitivity of 33.8 μCGy _air ^-1 cm ^-2 and the temporal response was determined to be ~40 ms by measuring the photocurrent decay after X-ray illumination.