Inkjet-Printed PbS QD-Graphene Infrared Photodetector with Enhanced Responsivity

Infrared photodetectors are crucial for detection, identification, and analysis, making them of paramount importance in both military and civilian applications. Graphene-based photodetectors integrated with colloidal quantum dots (CQDs) show great promise in the infrared spectrum, however, challenges remain in optimizing their performance and scalability. In this work, we present an innovative approach for fabricating high-performance infrared photodetector arrays by inkjet printing of colloidal lead sulfide (PbS) QDs onto graphene-based field-effect transistors (FETs) arrays. The incorporation of inorganic ligands Na₃AsS₄ significantly enhances the photodetector's responsivity up to 1276 A W⁻¹, which is nine times the responsivity of traditional ligand-functionalized devices. Additionally, the response time of the inorganic ligand device is 19 ms, two orders of magnitude faster than that of the EDT-functionalized device, due to the short-chain inorganic ligands significantly enhancing the charge transfer efficiency of the device. Furthermore, the inkjet printing technology is employed to enable precise deposition, thereby promoting the scalable fabrication of compact and high-resolution photodetector arrays. These findings highlight the potential of inkjet-printed QD–graphene photodetector arrays in infrared imaging and sensing applications, paving the way for large-scale fabrication of high-performance optoelectronic devices.