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

Abstract

Medical X-ray imaging procedures require digital flat detectors operating at low doses to reduce radiation health risks. Solution-processed organic-inorganic hybrid perovskites have characteristics that make them good candidates for the photoconductive layer of such sensitive detectors. 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 cm) 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.

A global plan for nature conservation

“…The 2015 Paris climate agreement states that global warming must be limited to a rise in temperature of less than 2 o C above pre-industrial levels to avoid the greatest impacts of climate change 1 . This goal has served as a rallying point for global efforts to limit carbon emissions.…”

Luminescent CH3NH3PbBr3/β‐Cyclodextrin Core/Shell Nanodots with Controlled Size and Ultrastability through Host‐Guest Interactions

“…20 nm). [1] These unique properties make them to be very promising candidates for the applications in lightemitting diodes (LEDs), [2] lasers [3] and solar cells. [4] Since the first report of a solution-based synthesis of colloidal CH 3 NH 3 PbBr 3 nanocrystals (MAPbBr 3 NCs), [5] great efforts have been made to control their size and geometry [6] that are required for their use in fabricating optoelectronic devices with excellent performances.…”

CH3NH3PbI3 and HC(NH2)2PbI3 Powders Synthesized from Low‐Grade PbI2: Single Precursor for High‐Efficiency Perovskite Solar Cells

“…[16] Owing to these superior properties, organolead halide perovskites have applicationst hat can be extended to X-ray detectors, lightemitting diodes, lasing, water splitting, and memristors, which also show excellent characteristics. [16][17][18][19][20][21][22][23] Despite the wide area of applications, the superior properties of PSCs critically rely on the quality of the perovskite layer, which depends on the experimental environment, such as the moisturel evel and/or temperature; [24][25][26][27][28] perovskite-coating procedures, including Lewis acid-base adduct approacha nd solvente ngineering; [8,10,29,30] and the purity of the raw materials. [31] Althoughc oating procedures to obtainh igh-quality perovskite seem to be established, because the PCEs of some PSCs surpass those of high-efficiency thin-film technologies (CIGS and CdTe), high PCEs can only be achieved by using highly pure PbI 2 .T he requirement for ah igh purity exceeding 99.99 %i sd ue to the fact that undesired materials in the raw materials, such as impurities, hydrated sources, and stabilizers, have often been found to be trap states,r esulting in as erious decreasei nc harge-carrier lifetimea nd the PL yield.…”