Flexible and stretchable photodetectors constructed by integrating photosensor, substrate, and electrode in one polymer matrix

Flexible photodetector (FPD) is a crucial component in modern wearable/flexible systems and plays a vital role in healthcare, environmental monitoring, flexible display, and other fields. However, achieving satisfactory interfacial adhesion among the electrode, photoactive material, and flexible substrate at the same time to fabricate FPDs with high flexibility, stretchability, stability, and mechanically compliance is still a challenge. In this study, we propose a green and eco-friendly water-system processing strategy to construct all-in-one FPDs, using borate ester polymers (BPs) as both the co-matrix of the photoactive layer substrate and the conductive ink. The flexible substrate exhibits a high adaptation to the conductive ink, and thus, efficient interface charge transfer with the complicated pattern electrode. The resulting FPD exhibits stable photoresponse under different bending angles and large mechanical strains. Even after 2000 cycles of light stimulation test at a whole device elongation of 50%, the FPD exhibits no significant decrease in the photoresponse performance. Such devices may provide new opportunities for multifunctional electronic skin and wearable electronic devices.