Molecular Doping of Flexible Lead‐Free Perovskite‐Polymer Thick Membranes for High‐Performance X‐Ray Detection

Abstract

X-ray detectors have broad applications in medicine and industry. Although flexible lead-free perovskite films are competitive because of their lightweight and low toxicity, they are less efficient due to low charge transport. Herein, we report low-toxicity, flexible X-ray detectors based on p-type doped MA 3 Bi 2 I 9 (MA = methylammonium) perovskitefilled membranes (PFMs). Strong coordination between dopant 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) and MA 3 Bi 2 I 9 and the establishment of charge-transfer complex (CPX) improved the conductivity by four times. The flexible X-ray detector achieved a high sensitivity of 2065 μC Gy air À 1 cm À 2 and an ultra-low detection limit of 2.71 nGy air s À 1 , which is among the highest values in all environmentally friendly flexible X-ray detectors. Importantly, the PFMs retained excellent charge transport under mechanical stress. All of those make flexible MA 3 Bi 2 I 9 membranes more competitive as next-generation X-ray detection.

Dense Perovskite Thick Film Enabled by Saturated Solution Filling for Sensitive X-ray Detection and Imaging

“…Compared with traditional α-Se and CZT materials, metal halide perovskites have characteristics such as easy preparation, containing elements with larger atomic numbers, and higher carrier mobility lifetime products (μτ), which make them ideal absorbing materials for X-ray detection. − Both single- and polycrystalline devices exhibit excellent X-ray detection performance. Compared with their single-crystalline counterparts, polycrystalline thick films can be deposited in large sizes, which offer significant advantages in flat panel detectors. − Various approaches have been developed to prepare large-sized polycrystalline perovskite thick films, such as blade-coating, evaporation, hot-pressing sintering, , spray-coating, screen printing, , and nylon film filling. − Kim et al developed a screen-printing method to prepare an 830 μm-thick perovskite thick film on a 10 cm × 10 cm TFT substrate . The obtained X-ray imaging panel had an X-ray sensitivity of 11 000 μC Gy air –1 cm –2 and produced a clear X-ray image of the hand.…”

Post‐Treatment of Metal Halide Perovskites: From Morphology Control, Defect Passivation to Band Alignment and Construction of Heterostructures

“…Organic-inorganic metal halide perovskites have been proved promising for photovoltaic, light emitting diode, and radiation detection applications. [1][2][3][4][5][6] Due to the unique photoelectrical properties, such as high absorption coefficient, long charge diffusion length, tunable bandgaps, etc., [7][8][9][10][11] perovskite solar cells (PSCs) have achieved a certified power conversion efficiency (PCE) of 26.1% in the lab. [12][13][14][15][16][17][18][19][20][21][22][23][24] Evolved from dye-sensitized solar cells and organic solar cells, diversified device architectures and processing techniques have been developed for fabricating PSCs.…”

Cs3Cu2I5 Nanocrystals with Near-Unity Photoluminescence Quantum Yield for Stable and High-Spatial-Resolution X-ray Imaging

“…X-rays are a kind of high-energy ionizing radiation with strong penetrating ability, which are widely used in various fields such as medical diagnosis, industrial inspection, high-energy physics, and public safety testing. − Scintillator-based indirect X-ray detectors can convert high-energy X-ray photons into low-energy ultraviolet or visible photons, which can be further detected by photodetectors such as amorphous silicon photodiodes, photomultiplier tubes, charge-coupled devices, or complementary metal-oxide semiconductor detectors. − The scintillator plays an important role in the above-mentioned process. Therefore, scintillators have been receiving great research attention, and, so far, commercial scintillators utilizing materials such as CdWO 4 , Bi 4 Ge 3 O 12 , LYSO, and CsI:Tl have been developed.…”