Strain-enhanced image recognition via piezo-phototronic effect in MnSe/α-In₂Se₃ heterostructure photodetector

The discovery of two-dimensional (2D) van der Waals materials has created unprecedented opportunities for flexible optoelectronics and bio-inspired neuromorphic systems. Here, we present a flexible broadband MnSe/α-In₂Se₃ p–n heterojunction photodetector that simultaneously achieves outstanding optoelectronic performance (1.28 A/W photoresponsivity, 9.11 × 10⁸ Jones detectivity, 353% external quantum efficiency at 450 nm) and strain-tunable response via the piezo-phototronic effect, demonstrating 203.9% enhancement under 0.303% tensile strain and 50.4% suppression under compression. The strain-modulated photoresponse enables direct coupling between optical and mechanical stimuli, where mechanical stimuli are directly converted into photocurrent variations without analog-to-digital conversion. Inspired by this mechanism, we develop a visuo-tactile fusion platform that integrates strain-gated signals as a fourth sensory channel. Implemented in an all-in-one architecture, the system achieves 86% recognition accuracy for Gaussian-blurred CIFAR-10 dataset with only 50 training epochs, while reducing system complexity compared to conventional multi-sensor platforms. This work not only demonstrates a novel heterostructure design for multi-dimensional optoelectronics but also reveals the potential of the piezo-phototronic effect in bio-inspired multisensory integration systems.