Organic-inorganic face-to-face ZnO NRs-based self-powered UV photodetectors: Heterojunction with poly(3,4-ethylenedioxyselenophene) and enhanced responsivity by carbon quantum dots

In this study, a novel organic-inorganic self-powered UV photodetector (UV PD) is realized by the face-to-face assembling of poly(3,4-ethylenedioxyselenophene) (PEDOS)/FTO and ZnO nanoarrays (ZnO NRs)/FTO. The ZnO NRs are further modified with carbon quantum dots (CQDs) to achieve high-performance capability of UV PD. As a hole transport material, PEDOS can enhance the charge transfer ability and form p-n heterojunction with ZnO NRs, which can separate the electron-hole pairs under the effect of the built-in electric field, making the UV PD achieve better photoelectric performance without external bias. In addition, a pyroelectric effect is found between ZnO NRs and CQDs and can greatly improve the photoresponsivity and shorten the response time of UV PD. The UV PD from CQDs-ZnO NRs/PEDOS has the excellent performance with photoresponsivity of 22.62 mA W−1 and response speed of 0.09 s/0.12 s (rise time/decay time) under the low ultraviolet light intensity (0.32 mW cm−2, wavelength 365 nm) at 0 V bias. This work provides an effective route to modulate the performance of UV PDs.