Rheological engineering of perovskite suspension toward high-resolution X-ray flat-panel detector

Abstract

Solution-processed polycrystalline perovskite film is promising for the next generation X-ray imaging. However, the spatial resolution of current perovskite X-ray panel detectors is far lower than the theoretical limit. Herein we find that the pixel level non-uniformity, also known as fixed pattern noise (FPN), is the chief culprit affecting the signal-to-noise ratio and reducing the resolution of perovskite detectors. We report a synergistic strategy of rheological engineering the perovskite suspensions to achieve X-ray FPDs with pixel-level high uniformity and near-to-limit spatial resolution. Our approach includes the addition of methylammonium iodide and polyacrylonitrile to the perovskite suspension, to synergistically enhance the flowability and particle stability of the oversaturated solution. The obtained suspension perfectly suits for the blade-coating process, avoiding the uneven distribution of solutes and particles within perovskite films. The assembled perovskite panel detector exhibits greatly improved FPN value (1.39%), high sensitivity (6.3×105 μC Gyair-1 cm−2), low detection limit (14.27 nGyair·s-1) as well as good working stability, close to the performance of single crystal detectors. Most importantly, the detector achieves a resolution of 0.51 lp/pix, exceeding all previous perovskite X-ray flat-panel detectors.

Mechanical-Chemical Coupled Synthesis for Long-Range Ordered Perovskites

“…Synthesis of highly-oriented directionally-aligned crystals represents an important materials advancement, and has yielded substantial improvements in functionalities in various disciplines, such as superior charge transport in semiconductors [1][2][3] , highly controllable phononic properties in thermal management 4,5 , and more efficient mechano-electric conversion in piezoelectric and acoustic devices 6,7 . Recently, halide perovskite materials have emerged as a multifunctional material with application potential in fields spanning solar energy harvesting [8][9][10] , optoelectronic sensing 11,12 , high energy radiation detection 13,14 , light emission diode 15,16 , ferro/piezo/thermoelectrics [17][18][19] , and several others. The development of advanced synthesis methodologies for these materials, particularly those that exhibit oriented lattice structures with long-range order and minimized lattice disorders, such as point defects, lattice mismatches, or inter-grain amorphisms, presents a significant opportunity 20 .…”