Nanophosphors, a catalyst for micro-LED technology development

With high optical power densities and small dimensions (typically inferior to 100 μm), micro-LEDs are considered as a major progress, opening new perspectives in smart displays conception, communication or medical fields. However, color conversion appears as a challenge that requires the development of efficient and stable nanophosphors. In this paper, a top-down approach to produce cerium doped yttrium aluminum garnet (YAG) nanocrystals (<50 nm) through high energy ball milling is reported. Results show that grinding is associated with a drop in optical performances which could be correlated with a partial amorphization of the particles and an in-situ cerium oxidation process. Then, a fragmentation mechanism, based on the performed morphological and structural analysis, is proposed.