Enhancement of color rendering index of stable lead-free perovskite WLEDs through incorporating green carbon dots

In this work, the carbon quantum dots@Cs2NaInCl6 (CDs@CNC) composites are presented by a facile solution synthesis. The obtained CDs@CNC composites maintain the octahedral morphology of original CNC host and the characteristic functional groups of original CDs. As a result, the rare-earth-free CDs@CNC composites exhibit green light emission with good stability for UV irradiation, heat, and humidity. In addition, CDs were combined with ion-doped CNC to obtain multicolor phosphor and the corresponding white light emitting diode (WLED) devices were fabricated by coating composites on commercial UV chips. The color render index (CRI) of WLEDs increases significantly from 66.24 to 90.95 while the cold-warm white fluorescence can be flexibly tuned by the change of excitation wavelength. The combination of CDs and double perovskites provide a new route to design white light emission phosphors, which could lead to the fabrication of next generation high-quality lighting devices.

Automated summary

In this study, carbon quantum dots@Cs2NaInCl6 (CDs@CNC) composites were synthesized using a simple solution method. The resulting CDs@CNC composites retained the octahedral morphology of the original CNC host and the characteristic functional groups of the original CDs. These rare-earth-free CDs@CNC composites exhibited green light emission with good stability under UV irradiation, heat, and humidity. Furthermore, by combining CDs with ion-doped CNC, multicolor phosphor was obtained and white light emitting diode (WLED) devices were fabricated, with the ability to flexibly tune the cold-warm white fluorescence by changing the excitation wavelength. The combination of CDs and double perovskites offers a new approach for designing white light emission phosphors, which may lead to the development of next-generation high-quality lighting devices.