Enhancement of efficiency and uniformity for green remote phosphor films and laminated white LEDs based on ZrO₂ microparticles

Green remote phosphor films (RPFs) with different ZrO₂ microparticle concentrations for blue LEDs were prepared based on their strong scattering effect; the laminated white LED (WLED) with blue LED and red RPF was packaged further. XRD, SEM and double integrate sphere were used to test the RPFs. Results showed that ZrO₂ microparticles were evenly dispersed in the silicon resin, the scattering effect significantly improves the utilization rate of excitation light and the transmission intensity of emission light, and the phosphor conversion efficiency (PCE) had a maximum value of 79.35% when ZrO₂ concentration was 0.88 wt%. The laminated WLEDs test showed that the luminous efficiency (LE) reached a highest value of 150.38 lm/W at the same concentration, which has increased by 6.37%; ZrO₂ microparticles can adjust the color rendering index (CRI) changed from 86.5 to 89.1, the correlated color temperature (CCT) gradually decreased from 4613 to 4219 K, and the CCT uniformity increased by 5.59%. Research shows that ZrO₂ microparticles have potential application value in the preparation of high-quality WLEDs.