One-step preparation of silica microspheres with super-stable ultralong room temperature phosphorescence†
Room temperature phosphorescence (RTP) materials often face the problems of relatively short lifetime (at the microsecond to millisecond level), poor stability or complicated synthesis. Because of these long-standing issues, RTP materials are unable to meet real needs. Herein, we present a new strategy for preparing super-stable ultralong room temperature phosphorescence (URTP) silica (SiO2) microspheres with lifetimes up to 1.26 s and excellent stability against oxygen, water, strong acids, bases and oxidizers, via a one-pot hydrolysis-assisted crosslinking carbonization method. In this strategy, carbonized polymer dots (CPDs) were generated via a crosslinking and carbonization process of EDA and TEOS under hydrothermal conditions, and CPD-embedded SiO2 microspheres (CPDs/SiO2 Ms) are formed by the hydrolysis reaction of TEOS simultaneously. The luminescence centres of the URTP CPDs/SiO2 Ms are the CPDs. The Si–O network effectively stabilized the triplet states of the CPDs and endowed the composite microspheres with super-stable URTP. As far as we know, this is the first report of such a stable URTP material. We believe that the facile strategy presented in this paper sheds new light on designing stable URTP materials and has wide potential applications in fields like photoelectric devices, anti-counterfeiting, time resolved imaging, etc.