Mixed‐Cation MAxCs1−xPbBr3 Perovskite Single Crystals with Composition Management for High‐Sensitivity X‐Ray Detection

• Published in: Physica status solidi. PSS-RRL. Rapid research letters 2020-10, Vol.14 (10), p.n/a
• Main Authors: Fan, Zhengfang, Liu, Jiang, Zuo, Wentao, Liu, Guoqiang, He, Xulin, Luo, Kun, Ye, Qinyan, Liao, Cheng
• Format: Article
• Language: English
• Subjects: Absorption spectra; antisolvents; Attenuation coefficients; Cations; Composition; composition management; Crystal growth; Crystal structure; Detectors; Electronic properties; Environmental monitoring; Medical imaging; Medical research; methylammoniumxCs1−xPbBr3; Perovskites; Photoelectric effect; Photoelectricity; Sandwich structures; Sensors; Single crystals; X-ray detection
• ISSN: 1862-6254; 1862-6270
• DOI: 10.1002/pssr.202000226

High‐sensitivity X‐ray detection is widely applied in medical imaging, environmental monitoring, and scientific research. Perovskite single crystals have been demonstrated to be a kind of potential material in X‐ray detection because of their large X‐ray attenuation coefficient, low crystal growth cost, and excellent photoelectric properties. In this study, a successful method to grow mixed‐cation MAxCs1−xPbBr3 single crystals with the assistance of an antisolvent and a highly sensitive X‐ray detector with symmetrical sandwich structure is reported. The analysis of absorption spectra of these crystals indicates the bandgap is tunable from 2.25 to 2.16 eV with increasing methylammonium (MA) compositions. Through the space‐charge‐limited current measurement, these mixed‐cation crystals achieve significantly improved electronic properties involving trap density, mobility, and conductivity, compared with the MAPbBr3 and CsPbBr3 crystals. The optimized electronic properties enable a high‐sensitivity X‐ray detector and a systematical analysis of crystal composition and detection performance. The X‐ray detectors based on mixed‐cation crystals exhibit a higher sensitivity and lower detection limit. The MA0.6Cs0.4PbBr3‐based detector achieves a sensitivity of up to 2017 μC Gyair−1 cm−2 and a detection limit of 1.2 μGyair s−1 under an applied voltage of 1 V, which is much better than our prepared MAPbBr3‐ and CsPbBr3‐based detectors. Mixed‐cation MAxCs1−xPbBr3 single crystals are synthesized for the first time with the assistance of an antisolvent. Composition management between Cs and methylammonium (MA) cations is conducted, resulting in tunable absorption onset. X‐ray response measurement demonstrates the mixed‐cation crystals achieve optimized properties with a higher sensitivity and lower detection limit.