Red and Near‐Infrared Thermally Activated Delayed Fluorescence Emitters Based on a Dibenzo[f,h]pyrido[2,3‐b]quinoxaline Acceptor
Year: 2025
Type: article
Abstract: Recently, there has been growing interest in deep red (DR) and near‐infrared (NIR) thermally activated delayed fluorescence (TADF) emitters due to their potential use in applications in bioimaging and night‐vision displays. Herein, we designed and synthesized a series of red/NIR TADF emitters, DMAC, PXZ, and DPACz, that all contain the same electron‐accepting PyBP (dibenzo [f, h] pyrido [2,3‐b]quinoxaline) moiety. These compounds emit at 643 nm for DMACPyBP, 722 nm for DPACz PyBP, and 743 nm for PXZPyBP in toluene solution, while their thin films singlet‐triplet energy gaps (ΔEST) are <0.1 eV. DMACPyBP, with the weakest donor, has the highest ΦPL of 62.3 %, the smallest ΔEST of 0.03 eV, and a fast reverse intersystem crossing rate constant (kRISC) of 0.5×105 s−1 in a 1 wt% doped film in CBP. In contrast, PXZPyBP, containing the strongest donor, has a lower ΦPL (21.2 %), a relatively larger ΔEST (0.10 eV), and a slower kRISC (0.04×105 s−1). Thus, our work highlights the molecular design challenges involved in pushing emission into the NIR region while maintaing both TADF and high ΦPL in PyBP‐based donor‐acceptor emitters.
Source: Chemistry - An Asian Journal
Institutions: University of St Andrews, London South Bank University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,520
OpenAlex ID: W4407987786