Efficient organic self-powered photoelectrochemical photodetectors based on conjugated polymers/fullerene heterojunctions

A new class of all-organic self-powered photoelectrochemical photodetectors (OPEC PDs) based on PDTBT-Qx/PC71BM were successfully constructed and the performance of PDTBT-Qx/PC71BM OPEC PDs was systematically evaluated. The synthesized copolymer PDTBT-Qx exhibited two dominant absorption peaks at around 370 nm and 700 nm and excellent thermal stability. Moreover, the energy level of PDTBT-Qx matches well with that of PC71BM, meaning good compatibility with PC71BM. Therefore, we applied PDTBT-Qx/PC71BM blend films as photoanode layers to fabricate a new class of OPEC PDs with a configuration of FTO/PDTBT-Qx/PC71BM/electrolyte/Pt/FTO. Compared with the photodetectors based on pure PC71BM films, the PDTBT-Qx/PC71BM OPEC PDs exhibited good UV-visible photoresponse with large responsivity (16.36 mA W-1 at 365 nm and 19.25 mA W-1 at 620 nm) and fast response speed (tau r/tau d values are 15 ms/20 ms at 365 nm and 20 ms/31 ms at 620 nm) without bias due to strong absorption of PDTBT-Qx and the increment of exciton dissociation efficiency at the interface between PDTBT-Qx and PC71BM. Additionally, the PDTBT-Qx/PC71BM OPEC PDs do not require a harsh preparation environment, and all the fabrication processes are conducted in air. All the results indicate the excellent self-powered photodetection ability of PDTBT-Qx/PC71BM OPEC PDs, suggesting a promising configuration in the field of optoelectronic applications. A new class of all-organic self-powered photoelectrochemical photodetectors (OPEC PDs) based on PDTBT-Qx/PC71BM were successfully constructed and the performance of PDTBT-Qx/PC71BM OPEC PDs was systematically evaluated.