Published in

Wiley, Advanced Materials, 29(35), 2023

DOI: 10.1002/adma.202211198

Links

Tools

Export citation

Search in Google Scholar

Optical Switching of Hole Transfer in Double‐Perovskite/Graphene Heterostructure

This paper was not found in any repository, but could be made available legally by the author.
This paper was not found in any repository, but could be made available legally by the author.

Full text: Unavailable

Green circle
Preprint: archiving allowed
Orange circle
Postprint: archiving restricted
Red circle
Published version: archiving forbidden
Data provided by SHERPA/RoMEO

Abstract

AbstractSynergically combining their respective ultrahigh charge mobility and strong light absorption, graphene (Gr)/semiconductor heterostructures are promising building blocks for efficient optoelectronics, particularly photodetectors. Charge transfer (CT) across the heterostructure interface crucially determines device efficiency and functionality. Here, it is reported that hole‐transfer processes dominate the ultrafast CT across strongly coupled double‐perovskite Cs2AgBiBr6/graphene (DP/Gr) heterostructures following optical excitation. While holes are the primary charges flowing across interfaces, their transfer direction, as well as efficiency, show a remarkable dependence on the excitation wavelength. For excitation with photon energies below the bandgap of DPs, the photoexcited hot holes in Gr can compete with the thermalization process and inject into in‐gap defect states in DPs. In contrast, above‐bandgap excitation of DP reverses the hole‐transfer direction, leading to hole transfer from the valence band of DPs to Gr. Experimental evidence that increasing the excitation photon energy enhances CT efficiency for both below‐ and above‐bandgap photoexcitation regimes is further provided, unveiling the positive role of excess energy in enhancing interfacial CT. The possibility of switching the hole‐transfer direction and thus the interfacial photogating field by tuning the excitation wavelength, provides a novel way to control the interfacial charge flow across a DP/Gr heterojunction.