Optoelectronics based on Transition Metal Dichalcogenide/2D Perovskite Heterostructures*

The use of 2D perovskites in visible-range optoelectronics has been limited due to their wide bandgaps, low optical absorption, and large exciton binding energies. [1,2] Here, through density functional theory calculations, we show that conjugating transition metal dichalcogenides (TMD) with 2D perovskites (here, BA₂PbBr₄, BA=C₄H₉NH₃⁺) to form heterostructures could enable different applications based on the bandstructure at the hetero-interface.
The MoS₂/2D perovskite junction demonstrates a type-II nature with a lower interface bandgap and the possibility of interlayer excitons which could be useful for photodetection and photovoltaics. On the other hand, light-emitting devices could be realized using the WSe₂/2D perovskite system that exhibits a type-I alignment, with bandgap in the visible region. Further, the electronic properties of the TMD/2D perovskite heterostructures show good tolerance to uniaxial and biaxial tensile strains. Along with this, the improved air stability and efficient charge transfer across the interface can enable the use of these heterojunctions in next-generation flexible optoelectronic devices.
References:
[1] K. Leng et al., Nat. Rev. Mater. (2020).
[2] L. Dou et al., Science (80-. ). 349, 1518 (2015).