Performance boosting of Sb2Se3 photodetectors by a sol–gel auto-combustion ZnO overlayer

•A sol–gel auto-combustion ZnO was firstly introducing in Sb2Se3 photodetector.•A (C4H10O6Zn: H12N2O12Zn = 6:4) ratio ZnO has higher crystallinity and light absorption.•The sol–gel auto-combustion ZnO protects Sb2Se3 from further oxidation.•The Sb2Se3/(6:4)ZnO PD show increased on/off ratio (22 times) and D* (10 times).•This work provides a new idea for Sb2Se3 and other heat-labile photodetectors. Antimony selenide (Sb2Se3) is a promising material for low-cost, high-performance optoelectronic devices. In this study, a sol–gel auto-combustion ZnO overlayer was introduced into the Sb2Se3 photodetector (PD) for the first time. The sol–gel auto-combustion method is simple, efficient and low-cost, and when the solution ratio of the ZnO overlayer (Zn(CH3COO)2·2H2O: Zn(NO3)2·6H2O) is optimized to 6:4, the constructed heterojunction improves the electron transport efficiency and shows the best performance. The results showed that the ameliorated PD exhibits higher on/off ratio (6054), responsivity (R) (23.5 mA W−1) and detectivity (D*) (2.1 × 1011 Jones) than the original device, which are improved by 22 times, 6 times and 10 times @ 660 nm, respectively. This work can enlighten the synthesis and application of low temperature ZnO thin film that can be applied for high performance Sb2Se3 PDs and other optoelectronic devices with heat-labile materials.