Unraveling the Crystallization Mechanism of Trinuclear Au Complexes Through Crystal Size-Dependent Luminescence

The trinuclear Au complex, DT4, demonstrates room-temperature phosphorescence (RTP) in the crystalline state, along with size-dependent polymorphism. The phase transition between the crystal polymorphs of DT4 can be directly observed in real time during crystal growth through changes in RTP color. This study aims to elucidate the crystallization mechanism of DT4, focusing specifically on determining the critical particle size at which crystal-to-crystal phase transitions occur during crystal growth. Graphical Abstract The gold complex, DT4, demonstrates a crystal size-dependent room-temperature phosphorescence color that can be observed during crystal growth from a solution. The luminescence properties and crystal size were continuously monitored throughout the growth process, facilitating the accurate determination of a critical particle size of approximately 3 mu m. The phase transition from the metastable to the stable phase occurs predominantly at this size.