One-step preparation of carbon dot-grafted trisodium citrate dihydrate for tunable photoluminescence and white light-emitting diodes

Abstract

Here we introduce an approach to prepare air-stable blue-light-emitting carbon dots (B-CDs) grafted trisodium citrate dihydrate (SC) at 200 °C with yields up to 93.0%. After annealing for 20 minutes at 200 °C, these CDs/SC present yellow-light-emitting CDs/SC (Y-CDs/SC) under UV excitation. CDs grafted SC namely CDs/SC, which can be synthesized via one-step solvent thermal method. The luminescence origins of B-CDs/SCs and Y-CDs/SCs are from two different types of CDs, which can be embedded in solid matrices (SC) to realize solid state fluorescence of CD-based composites. By tuning the mass ratio of B-CDs/SC to Y-CDs/SC, the color of the luminescence can be systematically tailored from greenish-yellow (0.333, 0.358) to light-blue (0.243, 0.247), or by adjusting the excitation wavelength, the color of the luminescence can also be regulated. Moreover, both B-CDs/SC and Y-CDs/SC are favorably used in white light-emitting diodes (WLEDs).