High-performance and stable hybrid photodetector based on a monolayer molybdenum disulfide (MoS2)/nitrogen doped graphene quantum dots (NH2 GQDs)/all-inorganic (CsPbBr3) perovskite nanocrystals triple junction

A high-performance and stable hybrid photodetector (PD) based on a monolayer MoS2/NH2 GQDs/CsPbBr3 triple junction is demonstrated in this work. The NH2 GQDs was introduced between the monolayer MoS2 and CsPbBr3 to enhance carrier transport and separation process, and optical absorption in the triple junction. The MoS2/NH2 GQDs/CsPbBr3 triple junction was characterized with several techniques. The ultraviolet-visible (UV-vis) and photoluminescence (PL) spectrometers reveal that the absorption and emission of the triple junction have significantly enhanced compared with that of the MoS2/CsPbBr3 bilayer junction, without the NH2 GQDs. In addition, the temperature-dependent photoluminescence (TDPL) confirms that the generated excitons in the hybrid triple structure tend to separate more easily during the device operation process. The hybrid photodetector shows a responsivity (R = 9.39 A/W), specific detectivity (D* = 3.32 x 10(12) J), and external quantum efficiency (EQE = 791%). Moreover, the performance of the hybrid photodetector not only outdo the performance of reported PDs based on 2D material (2DM)/perovskite and 2DM/2DM bilayer heterostructure, but also performance of PDs based on 2DM/2DM/2DM and silicon/2DM/2DM triple layer heterostructure. The enhanced performance of the hybrid PD was due to the excellent alignment between the MoS2, NH2 GQDs, and CsPbBr3, which enabled the triple junction to reduce recombination process and increase photon-absorption rate. These results pave the way for incorporating the NH2 GQDs with 2DM and perovskite to fabricate low-cost and high-performance optoelectronics.