Design of circadian white light-emitting diodes with tunable color temperature and nearly perfect color rendition

Abstract

The design of white light-emitting diodes is carried out to achieve highly efficient white light emission with superior color quality, good vision performance, and healthy effect on human circadian rhythms. Here, the white light is obtained by combing five different emissions (blue, cyan, green, yellow, and red) from organolead halide perovskites [MAPb(BrxI1-x)3, MA-CH3NH3]. The color characteristics are evaluated by calculating the CIE coordinates, the correlated-color temperature (CCT), the color-rendering indices (CRI: Ra, R9-R15), and the Duv. Vision performance is evaluated by calculating the luminous efficacy of radiation. The effect of white light on human circadian rhythms is evaluated by calculating the circadian action factor (CAF). The results show that the white lights with a tunable CCT from 2851 K to 8315 K, extremely high CRI (up to 98.7), and small Duv (0.0002 – 0.0055) have been obtained by engineering the spectral power distributions. In addition, excellent vision performance and highly tunable CAF are demonstrated. These findings demonstrate that these types of materials are promising candidates to achieve highly efficient white light emission with excellent color quality and vision performance.