Polymer-Structure-Induced Room-Temperature Phosphorescence of Carbon Dot Materials

As emerging carbon-based nanomaterials, carbon dots (CDs) are widely studied with regard to their luminescent properties. CDs obtained by the bottom-up method exhibit polymeric characteristics after crosslinking, polymerization, and incomplete carbonization processes, herein referred to as carbonized polymer dots (CPDs). In recent years, large progress has been achieved on the room-temperature phosphorescence (RTP) properties of CPDs. The developments and synthesis strategies for RTP CPD materials are reviewed. However, less attention has been devoted to the influence of polymeric structures on RTP of CPD materials. Polymer structures are a common feature of CPD materials. The extensive polymer structures are the key factors facilitating the RTP of CPD materials. Herein, the effects of the polymer structures on the RTP emission of self-protective CPD and matrix-assisted CPD materials are discussed. It is considered that the polymer structures can effectively immobilize sub-luminophores and protect triplet excited states to facilitate the RTP emission of CPD materials. The crosslink-enhanced emission (CEE) effect is proposed to further explain the RTP emission of CPD materials, which can provide an effective strategy to immobilize CPDs. Benefiting from CEE effect, efficient RTP can be achieved for CPD materials. The applications of CPD materials are then briefly summarized.