The methoxy-type silane coupling agents were synthesized via the modification of the hydrolyzable group and characterized to investigate the change in properties of silica/rubber composites based on the different silane coupling agent structures and the masterbatch fabrication methods. The prepared methoxy-type silane coupling agents exhibited higher reactivity towards hydrolysis compared to the conventional ethoxy-type one which led to the superior silanization to the silica filler surface modified for the reinforcement of styrene-butadiene rubber. The silica/rubber composites based on these methoxy-type silane coupling agents had the characteristics of more developed vulcanization and mechanical properties when fabricated as masterbatch products for tread materials of automobile tire surfaces. In particular, the dimethoxy-type silane coupling agent showed more enhanced rubber composite properties than the trimethoxy-type one, and the environmentally friendly wet masterbatch fabrication process was successfully optimized. The reactivity of the synthesized silane coupling agents toward hydrolysis was investigated by FITR spectroscopic analysis, and the mechanical properties of the prepared silica-reinforced rubber polymers were characterized using a moving die rheometer and a universal testing machine.

We synthesized cesium lead-halide perovskite colloidal nanocrystals using the hot injection method for wide-color-gamut low-cost displays. An efficient surface defect passivation technique was applied to further improve the optical performance of the green and red perovskite nanocrystals. The prepared perovskite nanocrystal solutions were formulated into inkjet printable homogeneous inks and uniformly printed on the substrate with appropriate surface control. They formed the wide-color-gamut color conversion layers of quantum dot organic light-emitting diode displays. We confirmed the excellent photophysical properties of the synthesized green/red perovskite nanocrystals and the inkjet printed color conversion layers with a photoluminescence quantum yield of 99.7%/96.2% and a wide color reproduction range of 117%.

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This study experimentally investigated process mechanisms and characteristics of newly developed xenon flash lamp lift-off (XF-LO) technology, a novel thin film lift-off method using a light to heat conversion layer (LTHC) and a xenon flash lamp (XFL). XF-LO technology was used to lift-off polyimide (PI) films of 8.68–19.6 μm thickness. When XFL energy irradiated to the LTHC was 2.61 J/cm2, the PI film was completely released from the carrier substrate. However, as the energy intensity of the XFL increased, it became increasingly difficult to completely release the PI film from the carrier substrate. Using thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and transmittance analysis, the process mechanism of XF-LO technology was investigated. Thermal durability of the PI film was found to deteriorate with increasing XFL energy intensity, resulting in structural deformation and increased roughness of the PI film surface. The optimum energy intensity of 2.61 J/cm2 or less was found to be effective for performing XF-LO technology. This study provides an attractive method for manufacturing flexible electronic boards outside the framework of existing laser lift-off (LLO) technology.

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Conventional fluorescent dyes have the property of decreasing fluorescence due to aggregation-caused quenching effects at high concentrations, whereas aggregation-induced emission dyes have the property of increasing fluorescence as they aggregate with each other. In this study, diketopyrrolopyrrole-based long-wavelength aggregation-induced emission dyes were used to prepare biocompatible nanoparticles suitable for bioimaging. Aggregation-induced emission nanoparticles with the best morphology and photoluminescence intensity were obtained through a fast, simple preparation method using an ultrasonicator. The optimally prepared nanoparticles from 3,6-bis(4-((E)-4-(bis(40-(1,2,2-triphenylvinyl)-[1,10-biphenyl]-4-yl)amino)styryl)phenyl)-2,5-dihexyl-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (DP-R2) with two functional groups having aggregation-induced emission properties and additional donating groups at the end of the triphenylamine groups were considered to have the greatest potential as a fluorescent probe for bioimaging. Furthermore, it was found that the tendency for aggregation-induced emission, which was apparent for the dye itself, became much more marked after the dyes were incorporated within nanoparticles. While the photoluminescence intensities of the dyes were observed to decrease rapidly over time, the prepared nanoparticles encapsulated within the biocompatible polymers maintained their initial optical properties very well. Lastly, when the cell viability test was conducted, excellent biocompatibility was demonstrated for each of the prepared nanoparticles.