Acquiring Charge‐Transfer‐Featured Single‐Molecule Ultralong Organic Room Temperature Phosphorescence via Through‐Space Electronic Coupling
Kuan Chen, Yanju Luo, Ming Sun, Chuanhao Liu, Mengjiao Jia, Caixia Fu, Xingsha Shen, Chuan Li, Xujun Zheng, Xuemei Pu, Yan Huang, Zhiyun Lu
Abstract
Abstract Although long‐lived triplet charge‐transfer ( 3 CT) state with high energy level has gained significant attention, the development of organic small molecules capable of achieving such states remains a major challenge. Herein, by using the through‐space electronic coupling effect, we have developed a compound, namely NIC‐DMAC, which has a long‐lived 3 CT state at the single‐molecule level with a lifetime of 210 ms and a high energy level of up to 2.50 eV. Through a combination of experimental and computational approaches, we have elucidated the photophysical processes of NIC‐DMAC, which involve sequential transitions from the first singlet excited state (S 1 ) that shows a 1 CT character to the first triplet excited state (T 1 ) that exhibits a local excited state feature ( 3 LE), and then to the second triplet excited state (T 2 ) that shows a 3 CT character (i.e., S 1 ( 1 CT)→T 1 ( 3 LE)→T 2 ( 3 CT)). The long lifetime and high energy level of its 3 CT state have enabled NIC‐DMAC as an initiator for photocuring in double patterning applications.