Controllable Afterglow Emission of Single-Mode to Dual-Mode Carbon Dot Composites Through Matrix Ratio Adjustment: An Approach to Optimize Glow Properties

Abstract

Room temperature afterglow materials have been widely concerned and applied in anti-counterfeiting, imaging and other fields, but many disadvantages of traditional afterglow materials in cost, environment and synthesis methods limited their development. In contrast, newer carbon point materials have attracted more research due to their many advantages and greater development potential, but it’s still difficult to effectively synthesize carbon point materials with both phosphorescence and delayed fluorescence. In this study, a series of long afterglow (261.2 ms) carbon dots composites, with single-mode and dual-mode afterglow emission, have been successfully prepared by inserting the carbon dots, synthesized from glucose and glycine, into a rigid boric acid matrix through a convenient two-step hydrothermal method. This series of carbon dot composites has achieved a transformation from single-mode phosphorescent emission to unique dual-mode afterglow emission, allowing for efficient environmental response color modulation. At different temperatures, the composites display different afterglow emissions dominated by either phosphorescent or delayed fluorescence. Based on their excellent temperature sensitivity, a single-mode long phosphorescence with a lifetime of 1.62 seconds was achieved at low temperature. Therefore, we have discovered a simple and efficient method to achieve dual-mode emission by adjusting the matrix proportion. In addition, the prepared carbon dot composites possess enormous potential for application, particularly for information encryption and anti-counterfeiting applications.

Keywords: Room temperature afterglow materials, carbon dot, single-mode and dual-mode, Controllable emissions