SnS/PEDOT:PSS Heterostructure-Based High Performance UV-Visible Photodetectors

This letter proposes a SnS2/PEDOT:PSS based heterojunction UV-visible light photodetector fabricated on ITO coated flexible PET substrate using the low-cost sol-gel spin coating method. The device shows respective responsivity, external quantum efficiency (EQE), detectivity and sensitivity of 182.89 A/W, $7.55\times 10^{{4}}$ %, $1.44\times 10^{{12}}$ Jones, and 4.40 at 300 nm (UV); 837.31 A/W, $2.30\times 10^{{5}}$ %, $5.24\times 10^{{12}}$ Jones and 20.15 at 450 nm (visible); and 706.94 A/W, $1.25\times 10^{{5}}$ %, $4.42\times 10^{{12}}$ Jones, and 17.01 at 700nm (visible). The transient measurement gives a rise-time ( $\text{t}_{\text {r}})$ of $27~\mu \text{s}$ and a fall time ( $\text{t}_{\text {f}})$ of $36~\mu \text{s}$ at 450 nm and −1 V bias. The high EQE is attributed to the photomultiplication effect resulted from the interfacial trap induced charge injection in organic photodetectors.