Achieving Efficient Organic Room-Temperature Phosphorescence through Acceptor Dendronization

, and suppress molecular motion. Consequently, it promotes intersystem crossing and triplet radiative transition while inhibiting nonradiative transition, thereby efficiently enhancing RTP emission. A proof-of-concept acceptor-dendronized dendrimer exhibits long phosphorescence lifetimes in the millisecond range in ambient solution and near 100% photoluminescent quantum yields in the doped films. This is the first reported RTP dendrimer to date. An OLED fabricated using this dendrimer in a sky-blue emission achieves an external quantum efficiency of 25.1%, which represents the state-of-the-art efficiency based on solution-processed RTP-OLEDs to date. Our findings offer definitive guidelines for the molecular engineering of RTP materials and pave the way for innovative RTP systems in diverse optoelectronic applications.