Thermal modulation for dual-mode high-temperature afterglow

High-temperature afterglow (HTA) materials have attracted significant attention due to their potential applications. However, triplet excitons are highly susceptible to thermal stimulation, leading to rapid deactivation, which limits the ability of organic afterglow materials to sustain long afterglow emission at high temperatures. In this work, a universal and effective strategy is proposed, wherein aromatic carboxylic acids (AMA) are dissolved in a hot boric acid (BA) solution, followed by drying and melt dehydration processing, successfully synthesizing a series of HTA materials. The BO matrix provides a rigid and thermally stable environment, effectively constraining molecular vibrations and preventing non-radiative transitions of triplet excitons. In this HTA material, both triplet hot exciton afterglow (HEA) and thermally activated delayed fluorescence (TADF) dual-mode emission are realized, along with tunable afterglow colors from blue to green. TCPB@BO demonstrates visible blue afterglow with a duration of 0.5 s and a long lifetime of 175 ms at 543 K. This synthetic strategy not only expands the application of HTA materials in anti-counterfeiting, but also offers protective solutions for temperature monitoring in electric vehicle batteries and chips in servers, with broad application prospects. It provides an innovative approach to preventing the detrimental effects of thermal damage in high-tech devices.