We report on the fabrication of a siloxane-encapsulated quantum dot (QD) film (QD-silox film), which exhibits stable emission intensity for over 1 month even at elevated temperature and humidity. QD-silox films are solidified via free radical addition reaction between oligosiloxane resin and ligand molecules on QDs. We prepare the QD-oligosiloxane resin by sol-gel condensation reaction of silane precursors with QDs blended in the precursor solution, forgoing ligand-exchange of QDs. The resulting QD-oligosiloxane resin remains optically clear after 40 days of storage, in contrast to other QD-containing resins which turn turbid and ultimately form sediments. QDs also disperse uniformly in the QD-silox film, whose photoluminescence (PL) quantum yield (QY) remains nearly unaltered under harsh conditions; for example, 85 °C/5% relative humidity (RH), 85 °C/85% RH, strongly acidic, and strongly basic environments for 40 days. The QD-silox film appears to remain equally emissive even after being immersed into boiling water (100 °C). Interestingly, the PL QY of the QD-silox film noticeably increases when the film is exposed to a moist environment, which opens a new, facile avenue to curing dimmed QD-containing films. Given its excellent stability, we envision that the QD-silox film is best suited in display applications, particularly as a PL-type down-conversion layer.

An ultraviolet (UV) transparent and stable methyl-siloxane hybrid material was prepared by a facile sol-gel method. The transparency and stability of a UV-LED encapsulant is an important issue because it affects UV light extraction efficiency and long-term reliability. We introduced a novel concept for UV-LED encapsulation using a thermally curable oligosiloxane resin. The encapsulant was fabricated by a hydrosilylation of hydrogen-methyl oligosiloxane resin and vinyl-methyl siloxane resin, and showed a comparable transmittance to polydimethylsiloxane (PDMS) in the UVB (∼300 nm) region. Most remarkably, the methyl-siloxane hybrid materials exhibited long-term UV stability under light soaking in UVB (∼300 nm) for 1000 h.

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We report the siloxane‐encapsulated quantum dot (QD) film (QD/siloxane film), whose photoluminescence (PL) quantum yield (QY) remains nearly undegraded under harsh heat or moisture conditions; 85°C/5% relative humidity (RH) and 85°C/85% RH for over 1 month.

Composition of siloxane hybrid material (hybrimer) was optimized to fabricate glass-fabric reinforced siloxane hybrid (GFRHybrimer) with high transparency and thermal stability. Refractive index of the hybrimer was precisely controlled by changing the phenyl precursor and adding a low refractive index crosslinker monomer. By measuring the thermal stability of GFRHybrimer films fabricated with a refractive index matched using cycloaliphatic epoxy oligosiloxane (CAEO), we obtained an optimal CAEO composition. The optimized GFRHybrimer film showed a high transparency (90%) and good thermal stability (1% weight loss temperature of 365 o C). Also, the fabricated GFRhybrimer film showed a smooth surface (R rms = 0.265 nm), low coefficient of thermal expansion (~14 ppm/ o C), and high elastic modulus (7 GPa).

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We report thermally cured siloxane encapsulated quantum-dot (QD) hybrid composite (thermal SE-QD). The thermal SE-QD shows superior thermal stability under harsh environment, which are 120 ℃ / 5 % relative humidity (RH) and 85 ℃ / 85 % RH, compared to previous out SE-QD.