High Performance of Simple Organic Phosphorescence Host-Guest Materials

<p><b>The study of purely organic room-temperature phosphorescence (RTP) has drawn </b><b>increasing attention </b><b>because of its considerable theoretical research and practical application </b><b>value</b><b>. Currently, organic RTP materials with both high efficiency (<i>Ф</i><sub>P</sub> > 20%) and a long lifetime (<i>τ</i><sub>P</sub> > 10 s) in air are still </b><b>scarce due to</b><b> the lack of related design guidance. Here, we </b><b>report</b><b> a new strategy to increase the phosphorescence performance of organic materials by integrating the RTP host and RTP guest in one doping system to form </b><b>a </b><b>triplet exciplex. With these materials, the high-contrast </b><b>labelling</b><b> of tumours in living mice and encrypted patterns in thermal printing are both successfully realized for the first time</b><b> by</b><b> taking </b><b>advantage of both</b><b> the long afterglow time (up to 25 min in aqueous media) and high phosphorescence efficiency (43%).</b></p>