Ambient Phosphor with High Efficiency and Long Lifetime in Poly(Methyl Methacrylate) Through Charge‐Transfer‐Mediated Triplet Exciton Formation for Photolithography Applications
Ruyi Liu, Chuanhao Liu, Caixia Fu, Zhenzhen Zhu, Kuan Chen, Chuan Li, Lingjie Wang, Yan Huang, Zhiyun Lu
Abstract
Abstract Currently, purely organic compounds showing ambient phosphorescence with high efficiency ( Φ P ) and ultra‐long lifetime ( τ P ) are quite rare and often need to be achieved in hydrophilic poly(vinyl alcohol)‐based hosts. This severely limits their applications. Here, we provide a solution to this issue by constructing an ortho ‐linked donor‐acceptor (D−A) dyad whose D moiety has not only a long‐lived T 1 state to achieve a long τ P , but also a T n state that is close to the S 1 state of the dyad to trigger effective spin‐orbit charge transfer intersystem crossing (SOCT‐ISC). The rationality of this strategy was validated by a new phosphor OF‐BCz that is able to show a τ P of 1.92 s and a Φ P of 30 % even in a less rigid matrix of poly(methyl methacrylate) (PMMA). Excitingly, OF‐BCz exhibited its potential as both a photocuring initiator and an in situ quality indicator, allowing for the visual detection of defects in photolithographic patterning.