Construction of Photoluminescence-Afterglow Dual-Mode White Emission from Carbon Dots via Förster Resonance Energy Transfer

Abstract

Carbon dots (CDs) have attracted much attention as their unique structures and fascinating optional properties. Recent years, multicolor CDs have been realized through the efforts of researchers. However, it remains a challenge to obtain CDs with photoluminescence (PL)-afterglow dual-mode white emission, which limits the application of CDs in the field of light emitting diodes (LEDs). Herein, an effective strategy is designed to prepare both white PL and afterglow CDs (w-CDs), which is to combine (3-aminopropyl)triethoxysilane (APTES) and orange fluorescence CDs (o-CDs) as precursors through hydrothermal reaction. During the synthesis of w-CDs, blue room temperature phosphorescence (RTP) CDs (b-CDs) formed by APTES were used as donor and o-CDs as acceptor. Depending on triplet-to-singlet Förster resonance energy transfer (FRET), the dual-mode white light CDs with the Commission Internationale de l’Eclairage (CIE) coordinate of (0.37, 0.37) of PL and (0.33, 0.37) of afterglow, and PL quantum yield (PLQY) of 32.44% were successfully prepared. Importantly, by changing the ratio of o-CDs, the color temperature of white afterglow can be easily adjusted from cold white to warm white. In addition, w-CDs have been successfully used in the fabrication of white LEDs (WLEDs) and dynamic display, applying to time-delay illumination and afterglow display.