Thermally enhanced luminescence (TEL)
We have been expanding the tool-box available to the field of Thermally Activated Delayed Fluorescence (TADF) and Room-Temperature Phosphorescence (RTP), and their novel thermal enhancement mechanism by developing low cost and modular donor(s)–acceptor (D-A/D2-A/D4-A) based solid-state light emitters. As a part of this effort, we developed thermal induced conformational change(TICC) as a mechanism for Thermally Enhanced Luminescence(TEL) at elevated temperatures above RT. The TEL at above RT developed so far is the earliest instance of a synthetic D-A conjugate in which the donor part rapidly tweaks its position when external thermal energy is supplied, and then switches back to the original position during cooling, which is a promising approach for the future design of controllable state-mixing systems. The ultimate goal of this approach is the design of novel conjugates that can ultimately lead to high quantum efficiency with shorter lifetimes via harvesting of both singlet and triplet states.
Most recently, we have been developing a new family of carbazole-quinoline conjugates that exhibit high PLQY and TEL above RT in doped films. So far, we planned to use these systems in state-mixing due to rotation of the donor, that can result high efficiency device operation. These initial results show how the development of new carbazole-quinoline conjugates brings about TEL that hitherto was not possible.