Piezo-phototronic effect promoted carrier separation in coaxial p-n junctions for self-powered photodetector

Sustainable and flexible photodetectors that simultaneously achieve sufficient responsivity and ultrafast speed is urgently needed to meet the booming of big data and portable electronics in our daily life. Herein, we demonstrate fiber-shaped photodetectors constructed by vertical organic-inorganic heterostructures, which achieves self-powered behavior and promoted photoresponse under series of coaxial p-n junctions and piezo-phototronic mechanism. Tunable photoresponse and ultrafast response and recovery (< 40 ms) are realized at zero bias by controlling bend-induced piezo-potentials of the photodetector. For the bended device with 1.96% strain, the photoresponse is enhanced 81.2% by the piezo-phototronic effect compared to the device under no strain. FEM simulation indicates that the non-uniform strain and piezo-potential distribution on the bended fiber device promotes carrier separation in the coaxial interfaces of p-n junctions, and thus improving the light detection ability. The present work provides a promising strategy for improving fiber-shaped photodetectors as well as a new idea for self-powered and ultrafast light detection in portable and wearable applications.