A Pure‐Red Doublet Emission with 90 % Quantum Yield: Stable, Colorless, Iodinated Triphenylmethane Solid
Chenghao Liu, Ehsan Hamzehpoor, Yoko Sakai‐Otsuka, Thaksen Jadhav, Dmitrii F. Perepichka
Abstract
Abstract Red luminescence is found in off‐white tris(iodoperchlorophenyl)methane ( 3I‐PTM H ) crystals which is characterized by a high photoluminescence quantum yield (PLQY 91 %) and color purity (CIE coordinates 0.66, 0.34). The emission originates from the doublet excited state of the neutral radical 3I‐PTM R , which is spontaneously formed and becomes embedded in the 3I‐PTM H matrix. The radical defect can also be deliberately introduced into 3I‐PTM H crystals which maintain a high PLQY with up to 4 % radical concentration. The immobilized iodinated radical demonstrates excellent photostability (estimated half‐life >1 year under continuous irradiation) and intriguing luminescent lifetime (69 ns). TD‐DFT calculations demonstrate that electron‐donating iodine atoms accelerate the radiative transition while the rigid halogen‐bonded matrix suppresses the nonradiative decay.