Multifunctional and High‐Performance FAPBI₃ Quantum Dots/Graphene UV Photodetectors by the Modulation of Photoconductivity

Abstract

Low‐dimensional devices with different photoconductive effects attract much attention in optoelectronics. In this work, negative photoconductivity (NPC) monolayer graphene photodetectors are fabricated by chemical vapor deposition (CVD), and a positive photoconductivity (PPC) photodetector is realized by decorating perovskite FAPbI3 quantum dots prepared by a simple and cost‐effective non‐polar solvent synthesis method on a graphene surface. The graphene‐based photodetector exhibits an NPC characteristic, which is attributed to the absorption and desorption of water molecules on the graphene surface. The responsivity of the photodetector with an NPC characteristic is −0.86 A W−1 under intense ultraviolet light irradiation, and the detectivity is −2.45 × 109 Jones. The FAPbI3 quantum dots/graphene photodetector with a PPC feature has a responsivity of 8.03 A W−1 and a detectivity of 1.89 × 1010 Jones under the irradiation of ultraviolet light of 365 nm and 55.3 mW cm−2 intensity. Due to the intense light absorption of perovskite combined with the extremely high mobility of graphene, photodetectors have high exciton separation and photocurrents when the devices are irradiated by ultraviolet light. Individual photodetectors are successfully created with NPC and PPC effects; the critical analysis for the different photoconductive mechanisms is provided, which will benefit the development of future multifunctional systems.

Colloidal quantum dots and two‐dimensional material heterostructures for photodetector applications

“…In recent years, 2D materials, such as graphene, BP, and TMDs, have gained significant attention and have shown great potential for photodetection applications 33,88–90 . Various methods have been developed for the fabrication of high‐quality single‐layer and multi‐layer 2D materials with controlled thickness and large‐scale production, including mechanical exfoliation, chemical vapor deposition (CVD), and epitaxial growth, liquid‐phase exfoliation, sputtering, solution‐processed methods, wet chemical approaches, and ternary‐solvent methods, and so on 15,91 …”

“…In recent years, 2D materials, such as graphene, BP, and TMDs, have gained significant attention and have shown great potential for photodetection applications. 33,[88][89][90] Various methods have been developed for the fabrication of high-quality single-layer and multi-layer 2D materials with controlled thickness and large-scale production, including mechanical exfoliation, chemical vapor deposition (CVD), and epitaxial growth, liquid-phase exfoliation, sputtering, solution-processed methods, wet chemical approaches, and ternary-solvent methods, and so on. 15,91 Owing to the weak van der Waals forces presented between the stacked layers of 2D materials, simple and cost-effective mechanical exfoliation methods continue to be the most commonly used approaches for fabricating single-layer and multi-layer 2D materials.…”