Recently, the Chemical Sensor Research Group (Group 106) of the Instrumental Analytical Chemistry Laboratory at Dalian Institute of Chemical Physics, led by Researcher Feng Liang and Associate Researcher Wang Yu, has made new progress in the controllable preparation and design of solid state emission (SSE) sensing materials for carbon dots. They have developed a gas assisted melt state polymerization method and combined it with a one-step reverse phase co precipitation method to prepare a series of wavelength tunable self-assembled SSE carbon dots (DICP dots), Dye-incorporated Carbonized Polymer Dots）。 This achievement solves the scientific problem of the complex structure and difficult control of optical properties of traditional SSE carbon dots, laying the foundation for the controllable design and preparation of carbon dot based photochemical sensing materials.

Carbon dots have attracted much attention in the field of chemical sensing due to their unique optical properties. However, due to the polydispersity and unclear definition of carbon dot structures, they are often simply regarded as a complete nanoparticle entity. Therefore, the main methods for synthesizing SSE type carbon dots used as sensing materials focus on overcoming the aggregation induced quenching (ACQ) phenomenon caused by electronic coupling within or between particles, including dispersing carbon dots in the matrix or substrate, establishing rigid cross-linking networks within carbon dots, introducing repulsion between carbon dot surfaces/polymer chains, and using AIEgen as a precursor for synthesis. However, these semi empirical preparation methods often result in uncontrollable solid-state fluorescence emission and complex structures that are difficult to characterize, posing significant challenges for sensing applications.

In response to this challenge, the team proposed a gas assisted molten state polymerization method, which achieved controllable preparation of carbon dots. The study found that the obtained product has a controllable and clear chemical structure, and exhibits self-assembled enhanced solid-state fluorescence properties. The team successfully prepared a series of novel DICP dots materials with full visible spectrum SSE by self-assembling selected fluorescent molecules into carbon dot fluorescent skeletons and utilizing the intra particle F ö rster resonance energy transfer (FRET) mechanism.

 This type of material has high fluorescence quantum yield, adjustable band structure, narrow emission line width, and exhibits high photostability in solution and solid. In addition, the team further validated the multifunctional application potential of DICP dots. The results indicate that doping self-assembly mediated functionalization of carbon dots is a reliable method, which can achieve various unique optical properties of carbon dots through the principle of intragranular fluorescence resonance energy transfer.

Source: Sensor Expert Network