Widely color-temperature low-luminosity-loss electrochromic-tuned white light-emitting diodes

Light-emitting diodes (LEDs) are efficient light sources extensively applied in people's daily life nowadays, with profound effect on their psychological and physiological state subtly and deeply. The correlated color temperature (CCT) the eyes perceive is a key parameter, but the CCT tuning technology of LEDs remains in the development stage. In this study, an electrochromic (EC) material is employed in the tuning device, exhibiting a wide CCT tuning range from 3,200 K to 6,900 K, varying almost along the black-body locus. The driving voltage is lower than 2.4 V, with luminosity loss less than 16%. Using the EC materials, the performance of CCT tuning technology is able to be further enhanced.