Perovskite sensors

Researchers from Westlake University, Hangzhou Dianzi University and Beijing BOE Optoelectronics Technology have demonstrated a monolithically integrated, active-matrix perovskite neuromorphic photodetector array that combines high-resolution imaging with in-sensor visual processing and prediction capabilities.

The team developed a 256×256 pixel array (65,536 pixels) with a density of 254 pixels per inch, fabricated by integrating blade-coated formamidinium lead iodide (FAPbI₃) perovskite films onto thin-film transistor (TFT) active-matrix backplanes. This architecture enables large-area operation with low crosstalk, addressing a key limitation of earlier dot-type or passive crossbar neuromorphic arrays that lack the scale required for high-resolution spatiotemporal imaging.

Researchers from Soochow University, Northwestern Polytechnical University, Yangzhou University and King Saud University have developed a broadband neuromorphic visual sensor capable of stable, all-day operation across both visible and near-infrared (Vis–NIR) spectral regimes. Inspired by the scotopic (low-light) vision of the cat eye, the device integrates optical sensing, temporal encoding, and synaptic plasticity within a single architecture, enabling efficient spatiotemporal perception under dynamically varying illumination.

The device is based on a vertically coupled heterostructure combining a narrow-bandgap FASn_0.5Pb_0.5I₃ perovskite absorber with defect-engineered SnS₂. This design leverages sulfur vacancy-mediated non-equilibrium carrier transport and trap-state dynamics to emulate retina-like temporal integration. Photogenerated carriers are captured and gradually released by defect states, creating a time-dependent transport process that naturally reproduces synaptic plasticity and temporal weighting without the need for complex external circuitry.

Researchers from China's Harbin Normal University and Air Force Engineering University have developed a lightweight, flexible wearable system that combines radiation shielding and real-time detection using CsPbBr₃ perovskite-based composite films.

The team addressed a longstanding challenge in radiation protection: integrating passive shielding and active monitoring into a single, wearable platform. Conventional lead-based materials provide strong attenuation but are heavy, rigid, and incapable of real-time response. In contrast, the newly developed system leverages the intrinsic high atomic number (Z) elements in CsPbBr_{3 -} cesium (Cs), lead (Pb), and bromine (Br) - to enable efficient photon attenuation while maintaining flexibility and low weight.

Researchers from the University of Potsdam, Fraunhofer Institute for Applied Polymer Research (IAP), Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Izmir Institute of Technology, Kastamonu University and Delft University of Technology have developed a flexible perovskite-based X-ray detector that combines record-level sensitivity with mechanical robustness, addressing a longstanding gap between high-performance rigid devices and flexible alternatives.

Metal halide perovskites (MHPs) are attractive for radiation detection due to their strong X-ray attenuation, high carrier mobility, and low exciton binding energy. However, top-performing devices have traditionally relied on rigid single crystals, while flexible thin-film counterparts have suffered from reduced sensitivity due to limited thickness and inferior crystallinity. To overcome this, the team introduced a polymer–perovskite composite embedded within a hydrophilic Teflon (PTFE) membrane approximately 200 µm thick, enabling both sufficient X-ray absorption and mechanical flexibility.

Researchers from China's Jiangsu University, Zhejiang Institute of Quality Sciences and Tianjin University have developed an additive-engineering strategy combined with polymer encapsulation to significantly improve the performance and stability of lead-free CsSnI₃ perovskite photodetectors.

Tin-based perovskites such as CsSnI₃ are considered strong candidates to replace lead-based materials due to their lower toxicity, cost advantages, and favorable optoelectronic properties, including tunable bandgaps, high absorption coefficients, and strong carrier mobility. These features make them particularly suitable for photodetection across the visible to near-infrared range. However, their practical deployment has been hindered by poor stability and performance degradation, primarily driven by the oxidation of Sn²⁺ to Sn⁴⁺.

Researchers from China's Hebei University and Shaanxi Normal University have developed a portable visual sensing platform for rapid, on-site detection of trace water content, leveraging H₂O-triggered lattice regulation in lead halide perovskite nanocrystals (HPNCs). The approach combines perovskite photophysics with a water-activated redox reaction to enable accurate, instrument-free analysis with performance comparable to the Karl Fischer (K–F) titration method.

Accurate trace water detection is critical across industries including chemical manufacturing, pharmaceuticals, food processing, and fuel systems, where even small amounts of water can degrade product quality, reduce stability, or introduce safety risks such as unwanted reactions or system failures. While K–F titration remains the standard technique, it requires specialized instrumentation and trained personnel, limiting its use to laboratory environments and preventing real-time, on-site monitoring.

Researchers at Jilin University, Nanchang University, Nanjing University of Posts & Telecommunications, Chinese Academy of Sciences and Westlake Institute for Optoelectronics have developed a new mechanism for high-performance narrowband photodetection in perovskite single crystals, based on a dynamically tunable space charge region driven by mobile ions.

Narrowband photodetectors are critical for applications such as environmental monitoring and biomedical sensing, where precise wavelength selectivity is required. While perovskites offer attractive optoelectronic properties and tunable bandgaps, their performance has traditionally fallen short of systems that combine broadband detectors with external optical filters. The researchers address this limitation by introducing a dynamic space charge region (DSCR) model that fundamentally alters how photocarriers are generated and collected.

Researchers from Rice University, Northwestern University, City University of New York, University of Rennes (CNRS), University of Lille (CNRS) and University of Nebraska-Lincoln have developed a new family of FA-based two-dimensional metal halide perovskites that come very close to a “perfect” crystal at room temperature. 

These hybrid (organic–inorganic) semiconductors are engineered to achieve near-maximal crystallographic symmetry, adopting a tetragonal P4/mmm space group without in-plane or out-of-plane octahedral distortions. In contrast to most 2D perovskites, whose softer lattices tend to distort and lower symmetry, the new materials maintain a highly ordered framework inspired by three-dimensional cubic (α-phase) FAPbI₃ (FA = formamidinium).

A research team led by Ulsan National Institute of Science and Technology (UNIST) has developed a new Meniscus Pixel Printing (MPP) technique that enables the direct, mask-free patterning of perovskite photodetectors onto contact lenses - paving the way for ultralight, eye-mounted extended reality (XR) systems and hands-free robotic interfaces.

(a) Schematic of the MPP. (b) Optical images of the MPP process with a 100 µm nozzle on the substrate. The scale bar is 200 µm. (c) Conceptual illustration of dwell time-dependent dot sizes control. (d) Schematic of the Solution-mediated perovskite crystallization pathway following MPP. (e) The optical images show the crystallization during the annealing process. The scale bar is 5 mm. (f) SEM image of the resulting perovskite layer. The scale bar is 10 µm. Image from: Advanced Functional Materials 

Integrating light sensors into a contact lens remains a challenge. Traditional lithographic and inkjet methods struggle to conform to the steep curvature of a lens surface and demand costly, multi-step processing. The team’s MPP approach addresses these obstacles by harnessing a self-confined liquid meniscus formed at the tip of a micro-pipette. In this configuration, the pipette briefly touches the substrate, forming a stable ink bridge that deposits a methylammonium lead iodide (MAPbI₃) perovskite dot with precise size control governed by dwell time and retraction speed.

Researchers from the University of Barcelona, Jaume I University, Slovak University of Technology and University of Valencia have engineered ultrasensitive photodetectors based on inkjet-printed nanocrystalline films of mixed-phase “raisin bread” CsPbBr₃/Cs₄PbBr₆ perovskite integrated onto graphene. By embedding photoactive CsPbBr₃ nanocrystals within a wider-bandgap Cs₄PbBr₆ matrix, the team creates a composite architecture that enhances charge confinement while simultaneously improving environmental stability relative to conventional perovskite films.

The raisin-bread morphology plays a central role in suppressing non-radiative recombination and mitigating degradation pathways that typically limit metal-halide perovskites in photodetector operation. In this configuration, the Cs₄PbBr₆ host passivates the surface of CsPbBr₃ nanodomains and acts as a protective scaffold, helping preserve optoelectronic properties over extended operation under ambient conditions. Coupled with solution-based inkjet deposition, this strategy demonstrates that complex phase-engineered perovskite microstructures can be reproducibly formed over large areas in a maskless, vacuum-free process, supporting low-cost, scalable manufacturing.