2023 Volume 81 Issue 5 Pages 492-500
Phosphorescence is a unique luminescence property with a number of advantages that are complementary to those of fluorescence. However, achieving efficient room-temperature phosphorescence (RTP) using metal-free organic molecules is a challenging task owing to the spin-forbidden nature of phosphorescence. Extensive research in the last decade has revealed that decent RTP can be obtained from organic crystals based on the suppression of nonradiative decay. Nonetheless, once the rigid crystalline lattice is destroyed by applying mechanical stimuli, such RTP often disappears. We have recently developed heteroaromatic 1,2-diketones as a novel scaffold of organic RTP. Unlike conventional phosphors, the diketones exhibit efficient RTP in various noncrystalline states/environments. This article describes the RTP of halogenated thienyl diketone derivatives, focusing on their response to mechanical stimuli and the multiple and indispensable roles of halogens therein.
