Computational analysis of angular colour variation in quantum-dot light-emitting diode devices

Inorganic colloidal quantum-dot light-emitting diodes (QD-LEDs) have emerged as highly promising devices for display and lighting applications, owing to their exceptional colour properties such as tunable emission wavelength and superior colour saturation. However, the complexity of the multilayered device architecture causes wavelength-dependent angular colour variations, deteriorating colour performance. In this study, the angular-dependent chromaticity shift and correlated colour temperature (CCT) variations of a white QD-LED device comprised of red, green, and blue devices are investigated using a systematic optimisation framework supported by extensive optical simulations. By employing the optical transfer matrix method and a discrete grid search method, it is found that the angular colour properties are highly sensitive to the thickness configurations of the multiple layers, emphasising the importance of precise architectural optimisation. Optimal layer thickness configurations are determined to minimise chromaticity shifts and ensure consistent CCT, achieving angular chromaticity differences below 0.02 and CCT values within 6500 ± 200 K over wide angular ranges. The proposed approach provides a robust methodology for advancing QD-LED technologies, ensuring reliable and consistent colour performance in both display and lighting applications.