Eliminating the Residual Ultraviolet Excitation Light and Increasing Quantum Dot Emission Intensity in LED Display Devices

Ultraviolet light-emitting diodes (UVLEDs) used as excitation sources for quantum dots (QDs) are promising candidates for the display field. To eliminate the residual excitation light, the conventional method is simply increasing the optical density of QDs for packaging, which would significantly reduce the luminous efficiency of QD-light-emitting diode (LED) devices owing to reabsorption loss. In this study, the combination strategy of a boron nitride (BN) reflective coating and an ultraviolet-reflection filter (UV-R filter) for QD-LED devices is proposed. By managing the recycle of UV light to excite more QDs and reducing the reabsorption effect of QDs carefully, their green emission intensity of LED using such a strategy is 82.0% higher than that of a conventional device with a similar QD light energy proportion of ~99.0% (almost no residual UV excitation light). This strategy is also effective for red QD-LED devices while eliminating residual UV excitation light and enhancing the red emission intensity. Therefore, this study provides an effective way to develop QD-LED devices with high QD emission intensity and low UV light leakage for display.