Long‐Persistent Luminescence of Organic Molecules With Low Photoluminescence Quantum Yield Induced by Efficient Energy Transfer

ABSTRACT Organic small‐molecule luminophores (SMLs) with low photoluminescence quantum yield (PLQY, Φ PL < 0.1) are commonly found in the field of optical research. However, existing strategies fail to induce their afterglow emission, as the excited‐state energy of these molecules is almost dissipated through non‐radiative transitions, which severely limits their practical applications. Here, we report a breakthrough strategy for converting non‐emissive SMLs into highly efficient delayed emitters. By constructing efficient energy transfer between low‐PLQY SMLs (acceptors) and energy donors within a thermoplastic polymer matrix, we achieve the first demonstration of delayed emission in such materials, with a delayed quantum yield of 28.9% and a delayed lifetime of 534 ms. In addition, the doped films offer distinct advantages in flat‐panel display applications, successfully achieving large‐area, high luminescence, and uniform ultraviolet projection display. This work marks a significant breakthrough in low‐PLQY molecular afterglow materials, laying a crucial material foundation and technical support for emerging applications, such as new display devices and ultraviolet projection technologies.