Self-powered flexible solar-blind ultraviolet photodetectors enabled by freestanding MXene/γ-Ga₂O₃ quantum dots...

Flexible solar-blind ultraviolet photodetectors hold immense promise for wearable electronics and environment monitoring yet face critical challenges in balancing mechanical robustness with photoresponse performance. This work demonstrates a novel, to the best of our knowledge, self-powered photodetector based on a Schottky junction formed between solution-processed γ-Ga₂O₃ quantum dots (QDs) and a freestanding Ti₃C₂T_x MXene film. The MXene film contributes metallic conductivity, mechanical flexibility, and a hydrophilic surface that facilitates solution-based assembly of γ-Ga₂O₃ QDs. The built-in electric field at the γ-Ga₂O₃ QDs/MXene interface enables efficient charge separation, allowing self-powered operation without external bias. Under 250 nm illumination, the device exhibits a photocurrent 10× higher than that of a rigid FTO-based counterpart. Notably, the photoresponse is further enhanced by applied tensile strain, which improves the conductivity of the MXene electrode. The device demonstrates millisecond-scale response to transient UV signals (e.g., arc discharges) and maintains stability after repeated bending. This strain-engineered architecture provides a promising platform for flexible optoelectronics capable of reliable operation in extreme conditions.