In this study, we investigate the photoluminescence stability of nanocomposites containing quantum dot (QD)/silica hybrid particles against high temperature and humidity. First, hybrid particles with different morphologies, such as silica/QD/silica (SQS), QD/mesoporous silica (MSQ), and QD/wrinkled silica (WSQ), were synthesized and dispersed in a commercially available silicone resin (Sylgard-184). We performed stability tests on these nanocomposites at 100 °C/85% RH for 72 h and found that their quantum efficiencies were maintained or even increased during the test, whereas a nanocomposite containing bare QDs exhibited a significant decrease in quantum efficiency. The enhancement in quantum efficiencies of the nanocomposites containing the MSQ and SQS particles was attributed to the photoactivation phenomenon. To further investigate the stability after exposure to heat and moisture, we measured quantum efficiencies of the photoactivated nanocomposites after storing them for 10 days under ambient conditions. Those efficiencies significantly decreased to values even lower than the initial values. However, quantum efficiency of the nanocomposite containing WSQ particles remained constant during and after the stability test because of the particle morphology. Therefore, we conclude that the nanocomposite containing the WSQ particles was most stable against high temperature and humidity and that the photoactivation was not desirable for the stability of nanocomposites, although it initially enhanced the photoluminescence properties.

The low stability of InP-based quantum dots (QDs) under high temperature and humidity is a major obstacle to their practical applications and commercialization. Herein, we report on the stability enhancement...

Quantum dot (QD)/colorless-polyimide (CPI) nanocomposites were fabricated and utilized as the color conversion layer in a light-emitting diode. CPIs with different lengths and end groups were synthesized and used both as surface ligands on the QDs and matrix polymers. Thereafter, nanocomposites were fabricated by the cross-linking reaction between the diphthalic anhydride-terminated matrix CPI and diamine-terminated CPI that was grafted onto the QDs. The degree of cross-linking in the nanocomposites was controlled by varying the length of the matrix CPI and QD concentrations; the highest quantum efficiency was observed at the highest degree of cross-linking because of the improved dispersion of the QDs. The cross-linked QD/CPI nanocomposite exhibited superior fluorescent properties and stability against heat and moisture to the un-cross-linked QD/CPI and QD/poly(methyl methacrylate) nanocomposites. Light-emitting diodes with high color accuracy and a wide color gamut were successfully fabricated using the cross-linked QD/CPI nanocomposite.

We report a novel synthesis of monodisperse In(Zn)P/ZnSe/ZnS quantum dots (QDs) with a high photoluminescence quantum yield and stability. The formation of metastable magic-sized clusters (MSCs) during reaction prevents separation of nucleation and growth stages and hence the synthesis of QD cores with narrow size distribution. The stability of MSCs was reduced by employing additives (i.e., tri-n-octylphosphine and zinc chloride) during the heating-up process, thereby inducing decarboxylation and ligand exchange reactions. The resulting QD cores exhibited a more uniform size distribution, and surface passivation from the additives improved their stability. The final product, In(Zn)P/ZnSe/ZnS QDs displayed a high photoluminescence quantum yield with narrow full-width at half-maximum, which could readily be used in display applications.

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