Deep Ultraviolet Photodetector with Ultrahigh Responsivity based on a Nitrogen‐Doped Graphene‐Modified Polypyrrole/SnO₂ Organic/Inorganic p–n Heterojunction

Abstract

Abstract Deep ultraviolet monitoring is realized via a high crystal quality SnO 2 microwire (MW)‐based photodetector (PD). This is then combined with 2D nitrogen‐doped graphene (NGr), conducting polymer polypyrrole (PPy), and an in situ polymerization‐fabricated composite film PPy‐NGr to construct an organic–inorganic p–n heterojunction PD. The long response time brought on by the oxygen adsorption of SnO 2 MW is greatly decreased via coating with the aforementioned materials. A defect response is created by the surface dangling bonds of SnO 2 MW, which can be effectively suppressed by the PPy. Absorption in the deep ultraviolet region (<240 nm) by PPy results in a blue shift of the response peak of the PPy/SnO 2 heterojunction PD compared to that of a single SnO 2 PD. The introduction of NGr improves the detection performance by providing a smoother energy band migration to reduce photogenerated carrier recombination and stacking at the potential barrier. The ultrahigh responsivity of PPy‐NGr/SnO 2 PD is 4594.25 A W −1 and the detectivity is 6.47 × 10 11 Jones, 40 and nine times greater, respectively, than those of a PPy/SnO 2 PD under a 5 V reverse bias and 240‐nm light irradiation (18.75 µW cm −2 ). The novel strategy provides a reference for the future design of high‐performance heterojunction PDs.