Printable organometallic perovskite enables large-area, low-dose X-ray imaging

• Published in: Nature (London) Vol. 550; no. 7674; pp. 87 - 91
• Main Authors: Kim, Yong Churl, Kim, Kwang Hee, Son, Dae-Yong, Jeong, Dong-Nyuk, Seo, Ja-Young, Choi, Yeong Suk, Han, In Taek, Lee, Sang Yoon, Park, Nam-Gyu
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05.10.2017; Nature Publishing Group
• Subjects: 639/624; 639/624/1111; Addition polymerization; Bremsstrahlung; Cesium; Crystals; Current carriers; Dark current; Detectors; Digital imaging; Energy harvesting; Equipment and supplies; Health risks; Humanities and Social Sciences; Imaging; Interlayers; Iodides; Irradiation; letter; Medical imaging; Methods; multidisciplinary; Optoelectronics; Perovskite; Perovskites; Photovoltaic cells; Polymer matrix composites; Polymers; Radiation; Radiography; Radiology; Science; Selenium; Single crystals; Technology application; Thallium; Thick films; Thin films; X-rays
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature24032

Highly sensitive all-solution-based detectors based on printable polycrystalline organometallic perovskite thick films enable X-ray imaging at low radiation doses and over large areas. Printable perovskites for X-ray devices Organometallic perovskite materials have received considerable attention in recent years owing to their high sensitivity to light, which has been exploited in a range of photoconductive and photovoltaic devices. X-ray detection is another particularly promising application for these materials because medical X-ray imaging machines that operate under lower doses would reduce radiation exposure. In Taek Han and colleagues demonstrate a flat-panel X-ray detector made by solution processing polycrystalline perovskites on a conventional thin-film transistor pixelated backplane, with sensitivities that are at least an order of magnitude higher than those of current commercial detectors. The approach could make low-dose X-ray imaging widely available and may also be extended to other photoconductive devices. Medical X-ray imaging procedures require digital flat detectors operating at low doses to reduce radiation health risks 1 , 2 . Solution-processed organic–inorganic hybrid perovskites have characteristics that make them good candidates for the photoconductive layer of such sensitive detectors 3 , 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 mGy air −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.