Tuning the Photon Sensitization Mechanism in Metal‐Halide‐Perovskite‐Based Nanocomposite Films Toward Highly Efficient and Stable X‐Ray Detection

Abstract

Metal halide perovskites (MHPs) have emerged as promising X‐ray detection materials. However, most MHP‐based X‐ray detectors are incompatible for large‐area preparation and integration, and suffer from the serious ion migration issue. This work demonstrates a “perovskite‐in‐a‐host” nanocomposite structure for X‐ray detection, by embedding the perovskite nanocrystal (PNC) sensitizers in the organic interpenetrating charge transport channels to work as the X‐ray attenuation layer. Intriguingly, the photon sensitization mechanism can be readily tuned from indirect‐ to direct‐type X‐ray conversion by decreasing the ligand density on the PNC surface, which significantly increases the sensitivity to 5 696 µC Gyair–1 cm–2. Besides, the ion migration gets suppressed due to the ion blocking effect of the surrounding organic phase. Therefore, an ultra‐small dark current relative drift of 3.57 × 10–9 cm s–1 V–1 is achieved even under an extremely large electric field up to 5 100 V cm–1, ensuring a low detection limit down to 72 nGyair s–1. The superior sensitivity and biasing stability enable the high performance X‐ray imaging capability of the devices, which exhibit great potential in scaling up and integration for the flat panel imaging.

Halide Perovskites and Their Derivatives for Efficient, High‐Resolution Direct Radiation Detection: Design Strategies and Applications

“…Reproduced with permission. [249] Copyright 2022, Wiley-VCH GmbH. c) X-ray rocking curves, with peak FWHM distribution inset, and d) trap density as a function of profiling distance (from top surface) measured using drive-level capacitance profile technique, for MAPbBr 3 single crystals grown without and with DPSI ligand.…”

Perovskite band engineering for high-performance X-ray detection

“…Not only X-ray generated carriers transportation can be enhanced but also ion migration can be suppressed. Wei et al [34] fabricated X-ray detector based on poly (3-hexylthiophene-2,5-diyl) (P3HT)/ CsPbBr 3 perovskite nanocrystals (PNCs)/(6,6)-Phenyl-C 61 butyric acid methyl ester (PCBM) as two type-II heterostructures [Figure 3A]. Since the X-ray was sensitized, carriers generated by X-ray in PNCs can be separated and transported to P3HT and PCBM quickly due to the alignment of band structure [Figure 3B].…”

Plasmonically‐Enhanced Radioluminescence Induced by Energy Transfer in Colloidal CsPbBr3 Nanocrystals via Hybridization of Silver Nanoparticles

“…[5,[15][16][17][18] In particular, lead halide perovskites (CsPbX 3 , where X = I, Br, and Cl) and methylammonium lead halide perovskites (MAPbX 3 , where MA = CH 3 NH 3 ) have been successfully demonstrated as X-ray imagers. [18][19][20][21] Extensive efforts have been invested in improving the X-ray detecting efficiency of scintillators; for example, hybridizing organic molecules (2,5-diphenyloxazole, PPO) with CsPbBr 3 nanocrystals significantly enhances the radioluminescence (RL) of these nanocrystals. [22] A mixture of organic molecules (perylene dyad 9,9′-bis[perylene-3,4-dicarboxylic-3,4-(N-(2,5-ditert-butylphenyl))]) and CsPbBr 3 nanocrystals shows a redshifted RL spectrum, indicating the possibility of using reabsorption-free waveguides.…”