Recently, Jiang Changlong, a researcher from the Institute of Solid State Physics of the Chinese Academy of Sciences Hefei Institute of Material Science, made progress in the field of multi-color long-life room temperature phosphorescent luminescent materials. The team has designed a new method to prepare carbonized polymer nanodot materials that can emit multi-color ultra long room temperature phosphorescence from blue to green. The relevant research results are published in Advanced Science.

Room temperature phosphorescence material is a special material that can continuously emit cold light after the excitation light source is turned off. It has application prospects in anti-counterfeiting, information encryption, display technology, and biological imaging fields. Among various room temperature phosphorescent materials, carbon dot materials have attracted much attention due to their simple preparation process, superior photostability, and low toxicity and environmental protection. However, traditional carbon dot materials face the problem of easy non radiative loss of triplet exciton energy, which makes it difficult to obtain long-lived and high brightness carbon dot room temperature phosphorescent materials. Meanwhile, due to the singularity of luminescent groups, achieving multicolor phosphorescence in the same carbon dot system is quite challenging. These issues limit the application of carbon dot based room temperature phosphorescent materials.

To address the aforementioned issues, the team designed carbonized polymer nanodots synthesized by hydrothermal method based on o-phenylenediamine and polyacrylic acid. The carbon dots were embedded into a rigid fixed matrix boron oxide (B2O3) through heat treatment, resulting in an ultra long RTP carbon dot composite material (oP CDs @ B2O3) with blue to green luminescence. The introduction of o-phenylenediamine provides rich multi-color luminescent centers for carbon dots by doping nitrogen atoms, while the long-chain structure of polyacrylic acid effectively fixes the luminescent chromophores inside the carbon dots, thereby reducing the non radiative loss of triplet excitons. In addition, the external rigid matrix boron oxide further reduces the energy loss of carbon dots through its rigid characteristics and strong interactions with carbon dots. Thanks to the unique polymer structure and the synergistic effect of the rigid matrix, oP CDs @ B2O3 exhibits a visible phosphorescence afterglow of up to 49 seconds, with a phosphorescence quantum yield of 19.5% and resistance to photobleaching. It has potential applications in information encryption and anti-counterfeiting.

The research work has received support from the National Key R&D Program, National Natural Science Foundation of China, Anhui Provincial Key R&D Program, and Anhui Provincial Natural Science Foundation.

Paper link：论文链接