Mechanically Compatible UV Photodetectors Based on Electrospun Free‐Standing Y³⁺‐Doped TiO₂ Nanofibrous Membranes with Enhanced Flexibility

Abstract

Abstract Free‐standing flexible TiO 2 nanofibrous membranes (NFMs) are highly desired for the construction of high‐performance wearable electronic devices. Nevertheless, tremendous challenges still exist due to the fragile characteristics of the polycrystalline TiO 2 nanofibers. Here, ultra‐flexible TiO 2 NFMs with robust fatigue strength and photoelectric properties are achieved via a simple element doping approach and the electrospinning technique. The 2 mol% Y 3+ ‐doped NFM‐based photodetector exhibits excellent UV detecting performance at 3 V under 350 nm illumination, that is, responsivity of 4.5 A W −1 , detectivity of 1.6 × 10 11 Jones, and photocurrent of ≈1.6 µA. By effectively tuning the distribution and bonding state of Y 3+ ions, the NFM shows significantly enhanced flexibility, where its original photocurrent is successfully maintained in various bending states (angle, radius, spiral state). Importantly, the resultant Y 3+ ‐doped TiO 2 NFM maintains ≈60% of its original photocurrent after bending at ≈145° for more than 20 000 times. A plausible prototype accounts for the effective bending deformation mechanism is proposed on the basis of the systematic analyses of the microstructural characteristics and the stress distribution achieved by using the finite element method. Finally, a wearable UV monitoring system that outputs real‐time photocurrent signals with different motion combinations of the remote‐controlled robot is demonstrated.