Flexible self-powered ultraviolet photodetector based on the GQDs: zinc oxide nanoflower heterojunction

Abstract

In this study, we present a flexible UV photodetector with a PET/ITO/GQDs: ZnO/PEDOS/ITO/PET structure, utilizing ZnO nanoflowers (ZnO NFs) which are more suitable for flexible devices. The close contact between the petal-like ZnO flakes helps maintain the integrity of the ZnO layer and mitigate cracking issues, while Graphene quantum dots (GQDs) fill the gaps between ZnO NFs, providing structural support and improving bending stability. Additionally, Se atoms in the PEDOS structure and oxygen-rich functional groups at the edges of GQDs interact with oxygen vacancies on the ZnO NFs surface, enhancing electron transport and further improving device performance. This flexible photodetector shows a high responsivity of up to 2.23 mA/W under room temperature and 0 V external bias (365 nm), with a detectivity of 1.949×10¹⁰ Jones, and response times of 0.074 s and 0.082 s. The device demonstrates good light response under different bending angles and after multiple bending cycles, maintaining its detection capability even after 1000 bends, with a responsivity of 1.02 mA/W and a detectivity of 9.930×10⁹ Jones. This indicates that the device possesses excellent flexibility and stability.