Efficiency enhancement of quantum dot-phosphor hybrid white-light-emitting diodes using a centrifugation-based quasi-horizontal separation structure.

In this paper, a centrifugation-based quasi-horizontal separation (c-HS) structure is proposed to enhance the QD light extraction of QD-phosphor hybrid white LEDs (WLEDs), effectively suppressing the backscattered loss from phosphor at the top region of the QD layer. Results indicate that a large centrifugation speed and dispensing mass of the QD layer is more beneficial to reducing the local density of phosphor at the top region, realizing quasi-horizontal separation between phosphor and QDs. Moreover, WLEDs with c-HS structure and conventional vertically layered packaging reference structure were compared at different correlated color temperatures (CCT). The radiant power and luminous flux achieved by the c-HS structure were 13.6% and 10.8%, respectively, higher than the reference structure at a typical warm white color of ∼4000 K. Consequently, this study can provide a new perspective on designing the separation structure for QD-phosphor hybrid WLEDs considering the backscattering loss of QD light.