A carbon dot-based time-dependent color-changing room temperature phosphorescent material with facile synthesis

Area of Science:

• Materials Science
• Nanotechnology
• Photochemistry

Background:

• Carbon dots (CDs) exhibit remarkable optical properties, leading to applications in anti-counterfeiting.
• While carbon dot-based room-temperature phosphorescent (RTP) materials are documented, those with time-dependent color-changing capabilities are scarce.

Purpose of the Study:

• To synthesize a novel carbon dot-based material exhibiting time-dependent color change from green to blue.
• To explore a simple and efficient method for preparing such advanced functional materials.

Main Methods:

• A facile one-pot heating method was employed using hydroxyurea as the sole precursor.
• Hydroxyurea served as both carbon and nitrogen source, and also formed a cyanuric acid matrix for uniform carbon dot dispersion.
• The time-dependent color change was achieved by tuning the ratio of dual emission centers within the carbon dots.

Main Results:

• Successfully prepared a carbon dot-based room-temperature phosphorescent material with green-to-blue time-dependent color-changing properties.
• The material formation involved hydroxyurea acting as a precursor and matrix component (cyanuric acid).
• The color transition was attributed to the modulation of intensity and color differences between dual emission centers.

Conclusions:

• A novel, simple, and effective method for creating time-dependent color-changing carbon dot-based RTP materials was demonstrated.
• This work provides a new strategy for designing advanced functional materials with tunable optical properties.
• The developed material holds potential for applications requiring dynamic visual responses, such as anti-counterfeiting.