Enhanced Resonance Energy Transfer and White-Light Emission in Carrot-Derived Carbon Dots: Utilizing Complementary Colors

Abstract

In this study, we explored resonance energy transfer (RET) between two carrot-derived carbon dots (S-CDs and P-CDs) and carrot extract (Crt), which eventually culminated in efficient white light emission (WLE). Herein, carrot extract acted as an acceptor, while S-CDs and P-CDs both served as donors. The S-CDs, and P-CDs were synthesized by the solvothermal treatment of carrot extract with sulfuric acid and phosphoric acid, respectively. The synthesized CDs were characterized using high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), Fourier transmission infra-red spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and fluorescence spectroscopy. Both S-CDs, and P-CDs exhibited spherical morphologies with an average diameter of 2.8 and 3.1 nm respectively. Remarkably, WLE was achieved both in solution and gel phases, the later formed using agar-agar. The Commission Internationale d’Eclairage (CIE) coordinates were (0.34, 0.32) in solution phase, closely aligning with the pure white light coordinates (0.33, 0.33). The correlated color temperature (CCT) for this mixture was 5041 K, indicating the cool nature of generated white light. Interestingly, the CIE coordinates of (0.31, 0.35) realized in the gel medium, also resembles very closely with that ofpureWLE. Detailed mechanistic investigations of resonance energy transfer (RET) were conducted using spectral overlap (J(λ)) and lifetime studies. The J(λ) values were 3.728×109 M-1cm-1 nm4 and 3.878×108 M-1cm-1 nm4 for the pair I (S-CDs + Crt) and pair II (P-CDs + Crt), respectively, while Forster distances (R0) were 0.79 nm and 0.54 nm for these pairs. To the best of our knowledge, this is the first report of WLE using two donors and one acceptor obtained from plant extract and their derived carbon dots.