“Impurity”-driven tunable organic room temperature phosphorescence <i>via</i> conformational regulation in multi host/guest systems

, singlet-to-singlet (SSET) and triplet-to-triplet (TTET). It presents a novel trace doping strategy for developing RTP materials with tunable optical features by synergistically controlling the ground and excited state geometries of a single guest molecule, which is rarely reported in the literature. Furthermore, by employing a suitable host matrix, we successfully stabilized a linear conformer of guest DPB in the ground state, which is otherwise unstable, and resulted in improved quantum yield. Simultaneously, we report unusual RTP from commercial BDCA, which we suspect to be caused by the presence of diphenylbenzil-based impurities, reiteratively emphasizing the importance of exercising caution whenever a system exhibits unusual properties.