Rubidium Doping to Enhance Carrier Transport in CsPbBr₃ Single Crystals for High-Performance X-Ray Detection

Abstract

The direct band gap CsPbBr3 perovskite is regarded as a promising alternative for low-cost and high-performance X-ray radiation detectors. Despite the fact that CsPbBr3 nanocrystals have been shown to be good scintillators in the indirect conversion mode, the direct X-ray conversion with CsPbBr3 single crystals is expected to yield higher spatial resolution. Here, rubidium (Rb) doping is demonstrated to be an efficient approach to improve carrier transport and X-ray detection performance in the direct-conversion X-ray detectors based on Cs(1–x)Rb x PbBr3 single crystals. Electrical properties’ characterizations as combined with X-ray photoelectron spectroscopy (XPS) measurements have revealed that Rb doping in Cs(1–x)Rb x PbBr3 single crystals can enhance the atomic interaction and orbital coupling between Pb and Br atoms, leading to an enhancement of carrier transport and X-ray detection performance. X-ray detectors based on a small amount (0.037%) of Rb-doped Cs(1–x)Rb x PbBr3 single crystals exhibited a high X-ray sensitivity of 8097 μC Gyair –1 cm–2. This work offers a feasible strategy to improve the X-ray detection performance by chemical doping in all-inorganic perovskite X-ray detectors.

Determination of X-ray detection limit and applications in perovskite X-ray detectors

“…However, the methodology on how to properly determine the detection limit has not been able to catch up with the rapid development of perovskite materials and their applications for X-ray detection. Many publications [12][13][14][16][17][18][19] have only reported the sensitivity of their perovskite X-ray detectors, while lacking the measure of the detection limits (Fig. 1).…”

Colloidal Synthesis and Tunable Multicolor Emission of Vacancy‐Ordered Cs2HfCl6 Perovskite Nanocrystals

“…From XPS analysis (Figure 2b,c), it is observed that the binding energy difference of Hf4f and Cl2p is increased by 0.16 eV with the incorporation of Sb 3+ . It means that the chemical interaction between the Hf 4+ cations and Cl – anions is somewhat enhanced, [ 20 ] which helps to stabilize the [HfCl 6 ] 2‐ octahedrons through suppressing the diffusion of Hf 4+ or Cl – ions away from [HfCl 6 ] 2‐ octahedrons or the break of the Hf–Cl bond during the NCs’ formation, thereby mitigating Hf 4+ as well as I ‐ vacancy defects of [HfCl 6 ] 2‐ octahedrons. As far as we know, Sb 3+ ‐ assisted passivation has rarely been achieved in the studies of perovskite NCs.…”

Halide perovskites: A dark horse for direct X‐ray imaging

“…Photoconductivity measurement indicated that the μτ product was increased from 4.9 × 10 −4 cm 2 V −1 for pristine CsPbBr 3 to 7.2 × 10 −4 cm 2 V −1 for RbCsPbBr 3 . As a result, the RbCsPbBr 3 detector delivered a much higher sensitivity of 8097 μC Gy air −1 cm −2 as compare to that of the CsPbBr 3 detector (918 μC Gy air −1 cm −2 ) 80 …”