Synthesis of Novel Hemicyanine Dyes for Color Compensating Film in Plasma Display Panels

Five novel cyanine dyes containing julolidine and indole moieties were synthesized. Several color compensating films for plasma display panels (PDP) were prepared using these dyes. The spectroscopic and physicochemical properties of the synthesized dyes in both solution and film state were evaluated. For each color compensating film, the optimum ratio of dye to binder was determined on the basis of transmittance, half band width, and photo-stability of the color compensating film. The five synthesized dyes showed sharp absorption peaks near 590 nm (orange light) and had molar extinction coefficients above $1{\times}10^5M^{-1}cm^{-1}$. The melting point of the dyes was above $200^{\circ}C$ and photo-stability of the color compensating films was improved by introducing substituents at the 5th position on the indole derivatives.