Near‐Infrared and Visible‐Range Optoelectronics in 2D Hybrid Perovskite/Transition Metal Dichalcogenide Heterostructures.

The application of ultrathin 2D perovskites in near‐infrared and visible‐range optoelectronics is limited owing to their inherent wide bandgaps, large excitonic binding energies, and low optical absorption at higher wavelengths. Here, it is shown that by tailoring interfacial band alignments via conjugation with low‐dimensional materials like monolayer transition metal dichalcogenides (TMD), the functionalities of 2D perovskites can be extended to diverse, visible‐range photophysical applications. Based on the choice of individual constituents in the 2D perovskite/TMD heterostructures, first principles calculations demonstrate widely tunable type‐II bandgaps, carrier effective masses, and band offsets to enable an effective separation of photogenerated excitons for enhanced photodetection and photovoltaic applications. In addition, the possibilities of achieving a type‐I band alignment for recombination‐based light emitters as well as a type‐III configuration for tunneling devices are shown. Further, the effect of strain on the electronic properties of the heterostructures are evaluated to show a significant strain tolerance, making them prospective candidates in flexible photosensors. [ABSTRACT FROM AUTHOR]