Organic Small Molecular Donors: Design, Synthesis And Photovoltaic Performance

Organic small molecular solar cells have attracted great interest due to theiradvantages of high purity, well-defined molecular structures, definite molecular weightsand high charge carrier mobility.In this thesis, the principle, structure and development state of organic smallmolecular solar cells are reviewed. Then three series of small molecular donor materialswere designed and synthesized. The band gap, energy level, charge carrier mobility andphotovoltaic properties were changed by modulating end-group, the length conjugatedlength and small molecular structures. The specific results of research were shown asfollows:1. A novel small molecular donor material TPD-CN were designed and synthesized,with TPD as the core. Research results showed that this material possesses broadabsorption.2. Three new star-shaped small molecules TPA-TBT-CN, TPA-TBT-R andTPA-TBT-V-CN with triphenylamine as the core were synthesized through Suzuki andHeck coupling reaction. These materials process good solubility and thermal stability.The absorption spectra were broadened via modulating end-group and the conjugatedlength.3. For further study of the relationship of the molecular structure and photovoltaicproperties of the organic photovoltaic materials two new linear small moleculesDPA-TBT-CN and DPA-TBT-R were designed and synthesized, with triphenylamine asthe core, benzothiadiazole as the bridge, and cyanoacetate and3-etylrhodanine used asthe end-group. Both materials show good solubility, thermal stability and broadabsorption.