Medical X-ray imaging procedures require digital flat detectors operating at low doses to reduce radiation health risks1,2. Solution-processed organic–inorganic hybrid perovskites have characteristics that make them good candidates for the photoconductive layer of such sensitive detectors3,4,5,6,7. However, such detectors have not yet been built on thin-film transistor arrays because it has been difficult to prepare thick perovskite films (more than a few hundred micrometres) over large areas (a detector is typically 50 centimetres by 50 centimetres). We report here an all-solution-based (in contrast to conventional vacuum processing) synthetic route to producing printable polycrystalline perovskites with sharply faceted large grains having morphologies and optoelectronic properties comparable to those of single crystals. High sensitivities of up to 11 microcoulombs per air KERMA of milligray per square centimetre (μC mGyair−1 cm−2) are achieved under irradiation with a 100-kilovolt bremsstrahlung source, which are at least one order of magnitude higher than the sensitivities achieved with currently used amorphous selenium or thallium-doped cesium iodide detectors. We demonstrate X-ray imaging in a conventional thin-film transistor substrate by embedding an 830-micrometre-thick perovskite film and an additional two interlayers of polymer/perovskite composites to provide conformal interfaces between perovskite films and electrodes that control dark currents and temporal charge carrier transportation. Such an all-solution-based perovskite detector could enable low-dose X-ray imaging, and could also be used in photoconductive devices for radiation imaging, sensing and energy harvesting.
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N.-G.P. acknowledges partial financial support from the National Research Foundation of Korea (NRF) grants funded by the Ministry of Science, ICT Future Planning (MSIP) of Korea under contracts NRF-2012M3A6A7054861 and NRF-2014M3A6A7060583 (Global Frontier R&D Program on Center for Multiscale Energy System) and NRF-2016M3D1A1027664 (Future Materials Discovery Program). Y.C.K., I.T.H. and S.Y.L. are indebted to all the members of SAIT (especially H. Kim and Y. Kim) and the Healthcare & Medical Equipment Division of Samsung Electronics (S. M. Yoon) for their help with the material characterization (SEM, X-ray diffraction, time-resolved photoluminescence and time-of-flight spectroscopy), X-ray detector fabrication, tape-automated bonding ROIC for the detector driving for its characterization, imaging processes and interpretation.