Jae Pil Kim

Synthesis and characterization of novel perylene dyes with new substituents at terminal-position as colorants for LCD color filter

AbstractnSix novel red perylene dyes were synthesized by modifying the bay- and terminal-positions of perylene main body to improve the optical performances of liquid crystal display (LCD) color filters. The absorption properties, solubility in industrial solvents and thermal stabilities of the dyes were examined to evaluate the dyes for dye-based LCD color filter. Mill bases and spin-coated color filters were formulated and fabricated using the synthesized dyes. Transmittance, dye aggregation and thermal stabilities of the prepared color filters were investigated using a color spectrophotometer. Geometric structures of the synthesized dyes were optimized by using Gaussian program. Five of the synthesized dyes showed acceptable optical properties as colorants for LCD color filters. Also, the synthesized dyes and prepared color filters exhibited suitable thermal stability for the application. Furthermore, the prepared color filters exhibited superior transmittances than pigment-based color filters at 650xa0nm. Their physical properties were closely related with chemical structures investigated by geometry optimization.

Synthesis and characterization of bay-substituted perylene dyes for LCD black matrix of low dielectric constant

Organic dyes with low electrical conductivity have recently been suggested as replacements for Cr/CrOx and carbon black in developing black matrices with low dielectric constants for liquid crystal displays (LCDs). Two perylene diimide dyes with broad absorption spectra were synthesized, and dye-type, hybrid-type and carbon black-type black matrices were fabricated using one of the dyes. Donating groups were substituted on the bay positions of the dyes by C–N coupling to enhance their solubility in propylene glycol methyl ether acetate, one of the most widely used industrial solvents in the LCD manufacturing processes. The thermal and spectral properties of the dyes were studied by thermogravimetric analysis and UV–Visible spectroscopy. Furthermore, the thermal, optical and dielectric properties of the black matrices were examined by color spectroscopy, optical density measurement and impedance analysis. The hybrid-type black matrix showed promising results with a low dielectric constant, low transmittance spectrum and high thermal stability.

Simple modification of basic dyes with bulky & symmetric WCAs for improving their solubilities in organic solvents without color change

A simple and easy solubility enhancement of basic dyes was performed with bulky and symmetric weakly coordinating anions (WCAs). The WCAs decreased the ionic character of the dyes by broadening the partial charge distribution and causing a screening effect on the ionic bonding. This new modification with WCAs has advantages in that it has no influence on the optical properties of the dyes. The solubilities of unmodified and modified dyes were tested in several organic solvents. X-ray powder diffraction patterns of the dyes were measured. Color films were prepared with the dyes and their color loci were analyzed to evaluate the optical properties. By the modification with WCAs, commercial basic dyes showed sufficient solubilities for be applied to various applications while preserving their superior optical properties.