Full-color biomass carbon dots for high-level information encryption and multi-color light emitting diode applications

Six biomass carbon dots (BCDs) with adjustable emission from 450 to 680 nm under a single wavelength excitation were successfully synthesized from spinach via solvent control strategy. The obtained BCDs show blue, green, yellow, violet, pink, and red emission with high photoluminescence quantum yield (PLQY = 12.68 ~ 30.77%). Detailed characterizations disclose that the tunable-emission mechanism is caused by the synergistic effect of carbon conjugate and surface oxidation degree. Meanwhile, full-color photoluminescence BCDs/PVP powder and BCDs/PVP/PVA films were fabricated by utilizing the prepared BCDs combined with polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA), respectively, which presented excellent high-level information encryption application. Importantly, multi-color and white light-emitting diode (LED) with Commission Internationale de L’ Eclairage (CIE) of blue (0.25, 0.29); green (0.25, 0.31); yellow (0.42, 0.45); red (0.52, 0.31); and white (0.32, 0.31) were achieved by only using our prepared BCDs. This work provides a valuable strategy of preparing multi-color BCDs using readily available biomass materials and paves a way for high-level information encryption and LED applications.

Graphical Abstract