Inch-Sized Thin Metal Halide Perovskite Single-Crystal Wafers for Sensitive X-Ray Detection

Abstract

Metal halide perovskite single crystals are a promising candidate for X-ray detection due to their large atomic number and high carrier mobility and lifetime. However, it is still challenging to grow large-area and thin single crystals directly onto substrates to meet real-world applications. In this work, millimeter-thick and inch-sized methylammonium lead tribromide (MAPbBr3) single-crystal wafers are grown directly on indium tin oxide (ITO) substrates through controlling the distance between solution surface and substrates. The single-crystal wafers are polished and treated with O3 to achieve smooth surface, lower trap density, and better electrical properties. X-ray detectors with a high sensitivity of 632 µC Gyair−1 cm−2 under –5 V and 525 µC Gyair−1 cm−2 under –1 V bias can be achieved. This work provides an effective way to fabricate substrate-integrated, large-area, and thickness-controlled perovskite single-crystal X-ray detectors, which is instructive for developing imaging application based on perovskite single crystals.

Perovskite band engineering for high-performance X-ray detection

“…In other ways, polishing method like O 3 -UV treatment can be applied to passivate surface defects. Feng et al [44] Essentially, both the insertion of SnO 2 and the addition of small organic molecules are a means of defects passivation. They are regarded as modifiers of electrical properties, such as carrier mobility and work function.…”

Halide Perovskite: A Promising Candidate for Next‐Generation X‐Ray Detectors

“…Sensitivity is a key parameter for direct‐type X‐ray detection that characterizes the ability of the detector to respond to a specific irradiation quantity. [ 19,20 ] High sensitivity indicates that X‐rays can induce a large photocurrent for a given irradiation dose rate, and it has a close relationship with the imaging quality. Generally, sensitivity ( S ) is determined by the collected charge per unit area under irradiation, which can be calculated by [ 8,21 ] $$$$\begin{equation}S = \frac{{{I}_{\rm{p}} - {I}_{\rm{d}}}}{{D \times A}}\end{equation}$$$$where I p and I d are the photocurrent and the dark current, respectively, while D is the X‐ray dose rate, and A is the effective detection area.…”

“…Sensitivity: Sensitivity is a key parameter for direct-type X-ray detection that characterizes the ability of the detector to respond to a specific irradiation quantity. [19,20] High sensitivity indicates that X-rays can induce a large photocurrent for a given irradiation dose rate, and it has a close relationship with the imaging quality. Generally, sensitivity (S) is determined by the collected charge per unit area under irradiation, which can be calculated by [8,21]…”

MAPb(Br1–xClx)3 Hybrid Perovskite Materials for Direct X-ray Detection

“…Methylammonium lead tribromide (MAPbBr 3 ) is among the most studied hybrid halide perovskites for high-energy radiation detection, ,, being more stable than its iodide-based counterpart, methylammonium lead triiodide (MAPbI 3 ) . Within our team, MAPbBr 3 SC growth via modified inverse temperature crystallization (MITC) has been optimized in dimethylformamide (DMF) for direct X-ray radiation detection. , Their optoelectronic properties have been evaluated under X-ray illumination, and while the growth optimization allowed reaching a very good sensitivity, they always presented a large dark current density J dark (∼μA cm – 2 ), being several orders of magnitude above the specifications required for radiation detectors .…”

“…2,3,6,7,12 From a fundamental point of view, working with SCs is the most favorable way to directly access their intrinsic bulk properties, which is critical to identify the best compounds for practical applications. Methylammonium lead tribromide (MAPbBr 3 ) is among the most studied hybrid halide perovskites for high-energy radiation detection, 3,4,13 being more stable than its iodidebased counterpart, methylammonium lead triiodide (MAPbI 3 ). 14 Within our team, MAPbBr 3 SC growth via modified inverse temperature crystallization (MITC) has been optimized in dimethylformamide (DMF) for direct X-ray radiation detection.…”