A Flexible MXene‐Black Phosphorus/Zinc Oxide Hybrid Structure with Excellent UVA‐Specific Photoelectric Sensing Properties for Human Skin Protection

Abstract Ultraviolet A (UVA) radiation causes various irreversible damages to human skin, so the research about UVA‐specific sensing device is urgent. 2D black phosphorus (BP) is used in many photosensors due to its advantages of high carrier mobility and tunable bandgap, but its application for UVA‐specific photosensor is not reported. Here, a MXene‐BP/Zinc oxide (ZnO) hybrid structure with lamellar‐spherical interfaces like finger lime fruit is prepared by the layer‐by‐layer assembly (LLA) method, and p‐n junctions are constructed between BP and ZnO with the Ti 3 C 2 T x electrode, showing excellent photoelectric performance. Density functional theory (DFT) calculations demonstrate that the enhanced performance is attributed to the rapid separation of photogenerated carriers in the presence of a built‐in electric field at interface. Furthermore, a flexible MXene‐BP/ZnO based UVA‐specific photosensor is prepared, which shows a specific response to UVA as high as 7 mA W −1 and excellent mechanical stability, maintaining 98.46% response after 100 bending cycles. In particular, the integrated anti‐UVA skin protection device shows excellent UVA‐specific identification and wireless transmission capability, which can provide timely UVA exposure information and skin protection warning for the visually impaired. This work demonstrates a new approach for further developments of advanced photoelectric sensing technology toward improving people's skin health protection.