Optimizing combination between thianthrene and benzophenone toward efficient room-temperature phosphorescence and oxygen sensing

Abstract

Purely organic room-temperature phosphorescence (RTP) materials show broad prospects for various applications due to their characteristics such as stimuli-responsiveness and high exciton utilization. A key challenge for improving the performance of purely organic RTP materials lies in suppressing non-radiative decay while enhancing spin–orbit coupling (SOC). To this end, we systematically combined benzophenone (BP) with thianthrene (TA) at different modification sites and with varying numbers of substituents, creating a class of high-efficiency RTP materials by leveraging the folded conformation of TA groups and introducing intramolecular charge transfer (ICT) to enhance SOC. Benefiting from the separated fluorescence–RTP dual emission of these materials, highly sensitive ratiometric optical oxygen sensing can be achieved with a Stern–Volmer coefficient of up to 10.65 kPa⁻¹. This study not only deepens the understanding of the structure–property relationship of TA-based RTP materials but also provides an effective strategy for performance enhancement and functional development of purely organic RTP materials.