Dual-interface MXene engineering for low-noise perovskite photodetectors in optical communication and health monitoring

Metal halide perovskite photodetectors (PDs) are attractive for next-generation optical communication and biomedical sensing owing to their high absorption coefficients, bandgap tunability, and solution-processability. However, their practical deployment is hindered by interfacial defects and ion migration, which result in high dark currents, noise, and limited operational stability. Here, we report a dual-interface (DI) engineering strategy that incorporates Ti 3 C 2 T x MXene simultaneously at the buried and top interfaces of the perovskite layer. This approach effectively passivates undercoordinated Pb 2+ /I − sites, suppresses trap-assisted recombination, and mitigates ion migration, thereby enabling ultralow-noise and fast-response devices. The optimized DI PD exhibits a suppressed dark current, a detectivity of 1.94 × 10 12 Jones, a responsivity of 0.44 A W −1 , and rise/fall times of 1.65/1.00 μs at 656 nm. The device retains >97 % of its performance after 60 days of nitrogen storage. Application demonstrations confirm error-free visible-light communication up to 10 kHz and precise photoplethysmography monitoring under varying illumination. This work highlights MXene-based DI engineering as a universal and scalable strategy for advancing high-performance perovskite PDs in data communication and healthcare technologies.