Room-Temperature Phosphorescence Achieved by Doping With Carbazole Derivatives in a Dimethyl Terephthalate Host

The host-guest doping strategy provides an effective approach to enhance the performance of organic room-temperature phosphorescence (RTP) and significantly expands the diversity of RTP materials. Nevertheless, achieving readily accessible and efficient host-guest RTP systems remains a significant challenge. Herein, we report a series of host-guest systems employing carbazole (Cz) derivatives as guest molecules and dimethyl terephthalate (DTT) as the host matrix. By tailoring substituents on the carbazole, the energy levels of the guest are finely regulated to achieve optimal matching with the host, enabling tunable RTP emission through modulation of the triplet-state energy gap. Notably, the optimized Cz@DTT system exhibits a long phosphorescence lifetime of up to 429.3 ms. Moreover, DTT demonstrates excellent versatility by forming efficient RTP systems with four distinct carbazole analogue guest molecules. This work establishes DTT as an easily accessible and highly adaptable host for RTP materials, offering a practical alternative to conventional polymer-based hosts.