Sunlike White Quantum Dot Light-Emitting Diodes with High Color Rendition Quality

Although it is demanded for general lighting sources to have high color rendition qualities close to natural daylight, it is difficult to make sunlike artificial illuminants due to limited tunability of phosphors and complicated fabrication processes. On the contrary, white-emitting quantum dot (QD) light-emitting diodes (QLEDs) can be easily produced by mixing several colors of QDs in a single emitting layer (EML). In this work, sunlike white QLEDs showing high color rendition qualities are demonstrated by incorporating five (red, yellow, green, cyan, and blue) or six (additional violet) primary colors of QDs in the EML. Based on the simulation and optimization of the multichromatic spectra, the pentachromatic and hexachromatic white QLEDs exhibit the superb color rendering index of 96-98, the color quality scales of 95-97, and the spectral similarity index of up to 86, with tunable correlated color temperatures from daylight to overcast sky. The Forster resonant energy transfers between six colors of QDs are also investigated with time-resolved photoluminescence spectroscopy. The analysis of the pentachromatic and hexachromatic white QLEDs with the sunlike spectra suggests that white QLEDs can be a promising candidate for next-generation solid-state lighting devices.