Atomistic Surface Passivation of CH ₃ NH ₃ PbI ₃ Perovskite Single Crystals for Highly Sensitive Coplanar-Structure X-Ray Detectors

Abstract

Organic-inorganic halide perovskites (OIHPs) are recognized as the promising next-generation X-ray detection materials. However, the device performance is largely limited by the ion migration issue of OIHPs. Here, we reported a simple atomistic surface passivation strategy with methylammonium iodide (MAI) to remarkably increase the ion migration activation energy of CH3NH3PbI3 single crystals. The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects, while not introducing extra mobile ions, which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100 V mm-1. The X-ray detectors hence exhibit a record-high sensitivity above 700,000 μC Gyair‐1 cm‐2 under continuum X-ray irradiation with energy up to 50 keV, which enables an ultralow X-ray detection limit down to 1.5 nGyair s-1. Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.

Recent Development in X-Ray Imaging Technology: Future and Challenges

“…Recently, solution-processed materials have been developed for advancing next-generation X-ray imaging technologies with low cost, high sensitivity, and flexibility. In particular, perovskites, featuring tunable bandgap, high photoluminescence quantum yields, narrow emission, and high charge-carrier mobility, have emerged as promising materials in photovoltaic devices, luminescence displays, and radiation detection [100][101][102][103]. The heavy atom-contained perovskites with efficient X-ray absorption show great potential in X-ray imaging applications.…”

Centimeter‐Sized Molecular Perovskite Crystal for Efficient X‐Ray Detection

“…The detector has a higher charge collection efficiency close to the crystal surface owing to a higher electric field strength. [30,31] The X-ray response of the TMCM-CdCl 3 crystal based device was recorded by modified DX-2700 X-ray diffractometer under a tungsten anode X-ray source at the continuous 40 kV acceleration voltage. The dose rates can be regulated by changing the X-ray tube current from 40 to 5 mA and number of the aluminum attenuators.…”

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

“…Jiajun Wei, Liting Tao, Liqi Li, Minxing Yan, Chenhao Wang, Wei Sun,* Deren Yang, and Yanjun Fang* DOI: 10.1002/adom.202102320 both indirect-and direct-type X-ray detection due to their constituent heavy atoms, large mobility-lifetime (µτ) product, high photoluminescence quantum yield, and solution-based low-cost preparation. [11][12][13][14][15][16] Among the multifarious kinds of perovskites, solution-grown perovskite single crystals demonstrate remarkable sensitivities and low detection limits in X-ray detection, such as MAPbI 3 , [17,18] (NH 4 ) 3 Bi 2 I 9 , [19] Cs 3 Bi 2 I 9 , [20] and MA 3 Bi 2 I 9 . [21][22][23] However, the limited size and low-throughput preparation of perovskite single crystals impede their further application on large-area flat panel X-ray imaging.…”