Synergistic energy and charge transfer dynamics in LD/3D perovskite heterojunctions for optoelectronic applications.

The functionality of low-dimensional (LD)/three-dimensional (3D) heterojunctions is governed by factors such as lattice mismatch, surface potential, and controlled growth conditions, all of which critically influence charge and energy transfer dynamics. By strategically tuning the heterointerface through optimised organic cations and conjugated ligands, efficient charge transfer and reduced recombination losses can be achieved, leading to improved power conversion efficiency for solar cells and luminescence quantum yield for light-emitting devices. This perspective explores the fundamental photophysical processes at the LD/3D interface, including exciton dissociation, charge carrier trapping, and electron-phonon coupling, which play a key role in determining device performance. We discuss the interplay of charge and energy transport mechanisms, focusing on Dexter energy transfer (DET), Förster resonance energy transfer (FRET), and triplet energy transfer (TET), and their impact on minimising non-radiative recombination and optimising charge extraction. Furthermore, we highlight how heterojunction engineering influences quasi-Fermi level splitting, built-in potential formation, and defect passivation, contributing to enhanced stability and long-term operational durability. A comprehensive understanding of these synergistic processes offers new pathways for the design of advanced perovskite-based optoelectronic devices, paving the way for next-generation high-performance photovoltaics and light-emitting applications.