Perovskite Photodetectors for Imaging and Computing

Solution processable perovskites are revolutionising the research field of direct X-ray detectors. Here, the authors discuss the opportunities, challenges, and research strategies for perovskite planar X-ray detectors.

Scintillators are materials of great interest for versatile and fast radiation detection systems. This Review discusses recent advances and strategies to improve the light yield, decay time, and coincidence timing resolution of all-inorganic and hybrid organic-inorganic perovskite scintillators.

Halide lead perovskites have emerged recently as possible candidates for high performance radiation detectors besides efficient solar cells. Here Wei et al. review the recent progress on perovskite based radiation detectors and suggest that they may compete with the conventional counterparts.

Low carrier mobility and degradation over time are key challenges to address in metal-halide perovskite photodetectors. Here, ultrasensitive photodetectors are reported based on inkjet-printed nanocrystalline films of a mixed-phase raisin bread halide perovskite, integrated on a graphene platform.

Feng et al. report a dynamic template-assisted strategy for depositing perovskite nanowire arrays across areas 12 times larger than the template itself, on diverse substrates. Large-area pixelated photodetectors with a responsivity of 1660A W⁻¹, detectivity of 3.9E14 Jones, and linear dynamic range of 160.3 dB are achieved.

Zhang et al. report a bulky Schottky junction constructed by interpenetrated macroporous-carbon electrode for hole extraction and perovskite network for electron trapping under X-ray irradiation. The efficient extraction of carriers enables a dry battery-powered portable X-ray radiation alarm.

Signal transmission without the interference from ambient light is prerequisite for optical communications. Min et al. design an asymmetric 2D-3D-2D perovskite photodetector with frequency-selective photoresponse for real-time high fidelity optical communications under strong light interference.

The water stability of perovskites remains challenging due to their intrinsic ionic nature. Here, the authors present water stable perovskite X-ray imager driven by strong cation-π interactions between organic cations and a complete release of microstrain during dimension transformation process.

Liu et al. report the design of organic cation to selectively enhance in-plane distortion for localizing excitons and suppress out-of-plane and intra-octahedral distortions for minimizing the formation of self-trapped excitons, enabling 2D perovskites with fast X-ray scintillation response (0.62 ns) and high light yield (19,700 photons MeV⁻¹).

Yang et al. report in-situ growth of ZnS(Ag)-CsPbBr3 heterostructures through all solid-phase synthesis for X-ray scintillators. The multiple contact sites promote light yield via efficient energy transfer from ZnS(Ag) into CsPbBr3 and enable fast decay for high-speed X-ray imaging at 200 fps.

Efficient light extraction in perovskite X/γ-ray scintillators is hindered by the small Stokes shift of exciton luminescence. Here, Jin et al. exploit the intrinsic strain in 2D perovskite as “self-wavelength shifting” to reduce the self-absorption effect without sacrificing the device response speed.

Xu et al. report reconfigurable phototransistors based on MAPbI₃/Bi₂O₂Se heterostructure, with momentum conservation promotes hot carrier extraction and interlayer carrier transport. Heterotransistor array enables traffic light signal detection under dim light, assisted by YOLOv4 neural network.

In-sensor computing requires detectors with polarity reconfigurability and linear responsivity. Pang et al. report a CsPbBr3 perovskite single crystal X-ray detector for edge extraction imaging with a data compression ratio of 46.4% and classification task with an accuracy of 100%.

Differential spectrometers recognise different wavelength via their differential photodetector responsivity. The authors combine an 8-pixel hemispherical perovskite photodetector with neural network algorithms to realise 3D trajectory tracking and 2D location tacking with colour classification.