InP/ZnSeS/ZnS Quantum Dot-Embedded Alumina Microbeads for Color-by-Blue Displays

Currently, heavy-shelled and gradient-shelled InP/ZnSeS/ZnS quantum dots (QDs) are commercially utilized as green (G) and red (R) color-converting layers in color-by-blue (B) QD-based displays. There is still a lack of systematic approaches to solve optical issues created when transforming QD nanoparticles into QD films. Here, triply protected approaches, such as using an Al dopant to passivate shell defects, Hf-n-butoxide (Hf(OtBu)4)-complex treatment to reduce ligand detachment, and the Al tri-sec-butoxide (Al(OsBu)3) electrospray (E-spray) process to form an outer protecting layer and transform the material into QD-embedded Al2O3 microbeads, are sequentially performed to improve the photoluminescence quantum yield (PLQY) and environmental stability of QDs. Moreover, QD-embedded microbeads improve QD distribution uniformity inside Al2O3 microbeads for high loading of nonagglomerated QDs and promote a scattering effect of QD green emission and blue excitation light in color-by-blue QD films. Therefore, the luminous efficacy (LE) of a mixed norland optical adhesive (NOA) film of QD@Al&Hf nanoparticles and QD@Al&Hf microbeads reaches ∼145.2 lm/W, which is 2.86 times higher than that of a QD@Al&Hf nanoparticle-only NOA film (50.8 lm/W). This combined approach can provide one example of promising combined approaches to fabrication of QD composite structures and suitable shapes for highly efficient and stable InP/ZnSeS/ZnS QD films in color-by-blue QD displays.