Design, Synthesis And Characterization Of Organic Semiconductor Materials With Large TPA Cross-sections

In this work, a series of organic semiconductor materials were designed and synthesized for two-photon absorption dyes. The aim of this work is to search for novel organic semiconductor materials with large two-photon absorbtion cross-sections and high solid fluorescent quantum yields. The research mainly focused on understanding the structure-property relationship of oligo(phenylene vinylene)s backbone.The main results are as below:1. A series of novel two-photon absorbton materials were designed, synthesized and optimized. We designed and synthesized oligo(phenylene vinylene)s (OPVs) derivatives by Horner-Wadsworth-Emmons reaction as the main backbone. The structures are modified by different electron-withdrawing or electron-donating groups. The effect of the substituted groups on the properties of OPV derivatives are discussed.2. The molecular packing of OPV molecules in the single-crystals was investigated. By using different end groups, the molecular packing in the solid sate is tailored. J-stack of OPV molecules was obtained which favors high solid fluorescence efficiency.3. The linear and nonlinear optical properties of OPV derivatives were investigated. Based on results of fluorescence quantumn yield and optical stability of OPVs derivatives, we studied the structure-properties relationship of the materials. Two photon absorption (TPA) cross-sections in solution and solid fluorescent quantum yields were studied and one materials with high TPA and solid fluorescence properties was found. Stimulated emission was observed from the single crystal of this materials.4. Prepartion of micro-and nanocrystals of selected molecules with different morphology was carried out by physical vapor deposition and solvent evaporation method. Optical waveguide properties were observed on organic microwires, which have potential to be applied in high performance of organic optoelectronics.