Zheng Yin1,2, Mingxing Gu3, Huili Ma3, Xueyan Jiang3, Jiahuan Zhi3, Yafei Wang1, Huifang Yang1, Weiguo Zhu1,2, Zhongfu An3. 1. National Experimental Demonstration Center for Materials Science and Engineering, Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials, Jiangsu Collaborative Innovation Center of Photovoltaic Science and Engineering, Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications, School of Materials Science & Engineering, Changzhou University, Changzhou, 213164, China. 2. College of Chemistry, Xiangtan University, Xiangtan, 411105, China. 3. Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China.
Abstract
It is an enormous challenge to achieve highly efficient organic room-temperature phosphorescence (RTP) with a long lifetime. We demonstrate that, by bridging the carbazole and halogenated phenyl ring with a methylene linker, RTP phosphors CzBX (X=Cl, Br) present high phosphorescence efficiency (ΦPh ). A ΦPh up to 38 % was obtained for CzBBr with a lifetime of 220 ms, which is much higher than that of compounds CzPX (X=Cl, Br) with a C-N bond as a linker (ΦPh <1 %). Single-crystal analysis and theoretical calculations revealed that, in the crystal phase, intermolecular π-Br interactions accelerate the intersystem crossing process, while tetrahedron-like structures induced by sp3 methylene linkers restrain the nonradiative decay channel, leading to the high phosphorescence efficiency in CzBBr. This research paves a new road toward highly efficient and long-lived RTP materials with potential applications in anti-counterfeiting or data encryption.
It is an enormous challenge to achieve highly efficient organic room-temperature phosphorescence (RTP) with a long lifetime. We demonstrate that, by bridging the <n class="Chemical">span class="Chemical">carbazole and halogenated phenyl ring with a methylene linker, RTP phospn>hors <span class="Chemical">CzBX (X=Cl, Br) present high phosphorescence efficiency (ΦPh ). A ΦPh up to 38 % was obtained for CzBBr with a lifetime of 220 ms, which is much higher than that of compounds <span class="Chemical">CzPX (X=Cl, Br) with a C-N bond as a linker (ΦPh <1 %). Single-crystal analysis and theoretical calculations revealed that, in the crystal phase, intermolecular π-Br interactions accelerate the intersystem crossing process, while tetrahedron-like structures induced by sp3 methylene linkers restrain the nonradiative decay channel, leading to the high phosphorescence efficiency in CzBBr. This research paves a new road toward highly efficient and long-lived RTP materials with potential applications in anti-counterfeiting or data encryption.