Forster energy transfer boosts indirect anisotropic interlayer excitons in 2L-MoSe2/perovskite heterostructures

TL;DR

This study demonstrates that energy transfer from ReS2 significantly enhances photoluminescence and induces optical anisotropy in interlayer excitons within 2L-MoSe2/perovskite heterostructures, opening new possibilities for polarization-sensitive optoelectronics.

Contribution

It reveals that Forster resonance energy transfer boosts emission and transfers optical anisotropy to interlayer excitons in 2D heterostructures, a novel approach for device applications.

Findings

PL increased by approximately eight-fold at room temperature due to FRET.

Emission intensity of indirect IXs nearly doubled at 78 K.

Optical anisotropy of ReS2 is transferred to 2L-MoSe2 and IXs, producing linear dichroism of ~1.1.

Abstract

Interlayer excitons (IXs) in two-dimensional (2D) van der Waals heterostructures have attracted considerable attention due to their unique optical and electronic properties. Owing to the spatially indirect nature, the radiative emission efficiency highly sensitive to interlayer twist angles. Further considering that their uniformly oriented out-of-plane dipole moments limit directional emission, strategies to simultaneously improve emission efficiency and induce optical anisotropy warrant in-depth investigation. In this work, we report significant photoluminescence (PL) enhancement and optical anisotropy of IXs in 2L-MoSe2/perovskite heterostructures mediated by energy transfer from ReS2. We attribute this enhancement to Forster resonance energy transfer (FRET), which increases the 2L-MoSe2 emission by approximately eight-fold at room temperature, and nearly doubles the emission intensity of momentum-indirect IXs in 2L-MoSe2/perovskite heterostructures at 78 K. Importantly, the optical anisotropy of ReS2 can be effectively imprinted onto 2L-MoSe2 and associated indirect IXs during the energy transfer process, yielding a linear dichroism of approximately 1.1 for both intralayer excitons and IXs with identical polarization directions. These findings expand the scope of IX study beyond direct bandgap materials with strong intrinsic emission to include systems with indirect bandgaps, offering new avenues for realizing high-performance polarization-sensitive optoelectronic devices.