Optical signatures of Förster-induced energy transfer in organic/TMD heterostructures

Abstract

Hybrid van der Waals heterostructures of organic semiconductors and transition metal dichalcogenides (TMDs) are promising candidates for various optoelectronic devices, such as solar cells and biosensors. Energy-transfer processes in these materials are crucial for the efficiency of such devices, yet they are poorly understood. In this work, we develop a fully microscopic theory describing the effect of the Förster interaction on exciton dynamics and optics in a WSe2/tetracene heterostack. We demonstrate that the differential absorption and time-resolved photoluminescence can be used to track the real-time evolution of excitons. We predict a strongly unidirectional energy transfer from the organic to the TMD layer. Furthermore, we explore the role temperature has in activating the Förster transfer and find a good agreement to previous experiments. Our results provide a blueprint to tune the light-harvesting efficiency through temperature, molecular orientation and interlayer separation in TMD/organic heterostructures.

van der Waals 2D transition metal dichalcogenide/organic hybridized heterostructures: recent breakthroughs and emerging prospects of the device

“…Nonradiative Förster resonance energy transfer (FRET) encompasses the efficient transfer of an excited electron–hole pair from an emitter (donor) to an absorbing medium (acceptor), facilitating the directed flow of energy from the donor to the acceptor. 128,140,184 The electron–hole coupling occurs through near-field interactions, wherein no photons are emitted and can be understood to the quenching of donor dipoles in the presence of a lossy medium. Several key factors influence the efficiency of nonradiative energy transfer, including the spectral overlap between the donor's emission and the acceptor's absorption, the spatial separation between the donor and the acceptor, the dimensionality of the materials involved, and the relative alignment of the donor and acceptor dipole moments.…”