Molecular and Nanoscale Control of Exciton Transfer in TADF-Sensitized Fluorescence

Abstract TADF-sensitized fluorescence (TSF), also known as hyperfluorescence, combines efficient triplet exciton harvesting with the narrowband emission of fluorescent emitters. Yet, its performance depends on the interplay between exciton conversion, energy transfer, and molecular organization across different length scales. Herein, we review recent progress in nanoscale exciton-transfer engineering for TSF, with emphasis on molecular excited-state dynamics, sensitizer-dopant spatial control, diversified energy-transfer pathways, and interlayer sensitization. These approaches regulate exciton conversion and lifetime, balance Förster and Dexter energy transfer, and control exciton distribution within emissive layers and across interfaces. We also discuss emerging directions including kinetic matching, spatial organization, and multiscale modeling for understanding the links between molecular structure, energy-transfer dynamics, and device performance. This Mini-Review provides profound insights into transforming random blend systems into controllable nanoscale exciton-transfer networks, paving the way for efficient narrowband TSF OLEDs.