Correlated color temperature alteration with changing the position of carbon dot film for warm WLEDs

Commercial white light emitting diodes (WLEDs) composed on the blue InGaN chip and YAG:Ce3+ phosphor have been used as a promising illumination sources. WLEDs with an adjustable correlated color temperature (CCT) are very important to the wide variety of applications. Herein, we represent a facile synthetic strategy to prepare green emission carbon dots by solvothermal method using citric acid and urea as a precursor. The carbon dots have a size about 4 nm and emission peak centered at 532 nm. The fabricated WLEDs present white light with variable color temperature from warm (5602 K) to cool white (9242 K) by combining YAG:Ce3+ and carbon dot films. Thus, the results show that the fabricated carbon dot and carbon dot film can be used in white sources in the next generation of lighting application as a CCT converter.