In view of the general aim of demonstrating on-chip color conversion by means of III-V QDs, QDOCCO has realized a number of significant project results:
*) InP-based QDs with a +90% PLQY can be reproducibly synthesized. This result is a major breakthrough in the realization of spectrum-on-demand light sources using on-chip color conversion since at such PLQY levels, the detrimental impact of self-absorption on the conversion efficiency can be minimized. Moreover, the developed synthesis protocol is scalable.
*) Multiple approaches can be used to form QD-in-polymer structures relevant for color conversion. These run from (1) direct deposition of a QD+polymer precursor formulation on the LED chip, followed by photocuring to (2) grinding of larger polymer parts, (3) formation of polymer beads through microflow, electrospray or reactive polymerization and (4) formation of QD-in-polymer structures (QD-pockets) by DLP.
*) Metal oxide coatings can be grown around QD-in-polymer structures by means of atomic layer deposition. Depending on the structure, such a coating can function as a barrier preventing QD degradation. In the case of QD pockets, accelerated ageing of thus encapsulated QD-in-polymer structure showed little indication of a loss of photoluminescence efficiency during exposure to high temperature and moisture.
*) QD-on-chip LEDs with a bespoke emission spectrum can be formed using a blue LED in combination with InP-based QDs as color convertor.