Development of Single Crystal CsPbBr3 Radiation Detectors from Low-Cost Solution Synthesized Material

Abstract

The all-inorganic perovskite CsPbBr3 is a strong candidate for room-temperature, semiconducting radiation detecting applications. With a high stopping power, a large bandgap, and a high mobility-lifetime (μτ) product for both holes and electrons, CsPbBr3 contains all the desirable properties of a room temperature radiation detector. Unfortunately, the production of detector-grade single crystal samples requires high quality starting materials, which must be further processed to achieve the desired purity for semiconducting operation. We have developed a modified zone refining method combining the continuous purification of ternary CsPbBr3 and the subsequent crystal growth step. Taking advantage of this technique, low-cost polycrystalline CsPbBr3 synthesized via solution chemistry processes can be directly used in the production of high-purity, detector-grade crystals. Semi-cylindrical CsPbBr3 single crystal ingots up to 120 mm in length and 22 mm in diameter were obtained. The final product exhibited good chemical stoichiometry and high trace metal purity (2.34 ppm across 73 elements). Detector devices fabricated from the crystal wafers displayed resistivities > 2.0 × 108 Ω·cm and high photocurrent responses. The radiation detectors were able to produce spectroscopy responses to 241Am α-particle. The hole mobility-lifetime (μτH) product of the detectors was determined to be in the range of 1.45 × 10−3 cm2/V.