Carbon dots-based room temperature phosphorescent (RTP) materials have attracted widespread attention owing to their excellent optical properties. However, there still is a challenge to fabricate carbon dots-based materials simultaneously showing long RTP lifetime and high phosphorescent quantum yield. Herein, we have designed a kind of carbon dots–silica hybrid material that can produce RTP emission with ultralong lifetime and also high phosphorescent quantum yield (1.3 s and 11.22%). Both chemical and optical analytical characterizations indicate the source of the outstanding RTP performance as the synergistic strategy of abundant electron traps, highly rigid network, and stable covalent bond. The findings provide a new design idea to achieve novel carbon dots-based RTP materials, showing broad application prospects in optical anticounterfeiting, optoelectronics, and others.

Aggregation-induced phosphorescence (AIP) has attracted much attention for its unique luminescent characteristics. Nevertheless, this fascinating phenomenon is rarely reported in the field of carbon dots (CDs). Herein, a simple method to prepare CDs simultaneously with dispersion-state fluorescence, aggregation-state fluorescence, and phosphorescence is presented by a one-step solvothermal process. The resultant AIP CDs (A-CDs) display a long afterglow lifetime of 0.51 s in the aggregation state, lasting about 5 s to the naked eye. The phosphorescence emission of A-CDs resulted from the rigid, protective structure due to the aggregation state. In addition, inorganic silica has been employed as a doping matrix to effectively improve phosphorescent properties (1.11 s). Benefitting from the unique luminescence feature and excellent water dispersibility, the A-CDs can be dispersed directly in water, and the phosphorescent emission could be controlled by regulating the concentration, thus enabling information encryption.