Enhanced Photoresponsivity of Perovskite QDs/Graphene Hybrid Gate-Free Photodetector by Morphologically Controlled Plasmonic Au Nanocrystals

摘要

Owing to their excellent carrier mobility, high absorption coefficient,exceptional quantum efficiency, and low-cost solution processability,perovskite quantum dots (PQDs) are a promising candidate forphotodetection. However, PQDs-based photodetectors typically show pooroptoelectronic performances, mainly limited by their weak light–matterinteraction. In this work, MAPbBr3 PQDs are hybridized with graphene(Gr) and morphologically controlled plasmonic gold nanocrystals (AuNCs) todemonstrate a superior photodetector at 432 nm through a synergetic effect.The experimental results indicate that three shaped AuNCs (i.e., sphere, theoctahedron (OD), and rhombic dodecahedron (RD)) all contribute to betterphotodetection behaviors due to surface trap state passivation and enhancedcharge carrier densities with longer lifetime compared to that of pristinePQDs. In particular, the PQDs/RD-AuNCs/Gr system demonstrates arecord-high responsivity of 2.7 × 105 A W~（?1）, a detectivity of 4.9 × 10~（13） Jones,and external quantum efficiency (EQE) of 7.9 × 10~7 at 1.6 μW cm~（?2）illumination power density of 432 nm wavelength with a lowest appliedvoltage of 1.0 V for a gate-free PQDs/AuNCs/Gr-based photodetector.Furthermore, to the authors’ knowledge, this device shows the highestresponsivity among the PQDs/AuNCs/Gr-based electrostatic gate-free lateralconfiguration photodetectors.