Aggregation-assisted energy gap modulation controls delayed emission in hybrid charge-transfer emitters.

ABSTRACT: Exploring the impact of molecular aggregation on excited-state energy landscapes is key to tailoring long-lived delayed emission in organic materials. Here, we demonstrate aggregation-assisted energy gap modulation governing the balance between delayed fluorescence (DF) and room-temperature phosphorescence (RTP) in the indole-based hybrid charge-transfer emitters - HD and its brominated analogue BrD. In HD, J-aggregation, facilitated by a collinear molecular arrangement, significantly reduces the singlet-triplet energy gap (ΔE _ST), enhances reverse intersystem crossing (RISC), and increases the efficiency of radiative decay from the regenerated singlet state, thereby favouring DF. In contrast, BrD forms H-aggregates through strong π-π interactions, which increase ΔE

SUBMITTER: Vinod K 

PROVIDER: S-EPMC12309850 | biostudies-literature | 2025 Jul

REPOSITORIES: biostudies-literature