Synthesis And Photovoltaic Properties Of Conjugated Copolymers And Organic Molecular With The Bridge Of Benzodiathiazole Units

As we know, the increasingly serious energy crisis on the earth, and solar energywith its endless and no pollution and other characteristics as the primary choiceinstead of other traditional energy sources, and therefore solar cells become a hotresearch and development for experts and scholars from all over the world. In thisdissertation, polymer solar cell materials, small molecule bulk heterojunction and dyesensitized solar cells and materials research progress are reviewed. In order to broadenthe solar cell material absorption spectra, increase the open circuit voltage andimprove the stability of the material, so as to research and development of bettermaterials and to improve the power energy conversion efficiency of organic solar cells,we designed and synthesized two new three-dimensional conjugate polymers withbenzo[1,2-b:4,5-b′]dithiophene （BDT） as bridge chain. In the mean time, we alsosynthesized two donors-π-acceptor （D-π-A） organic small molecule and applied inbulk heterojunction and dye sensitized solar cells respectively. The compounds werecharacterized by flight time mass spectrometry, nuclear magnetic resonance （NMR）and infrared spectrum, and the electrochemical, photophysical and photovoltaicperformance were measured by cyclic voltammetry, fluorescence spectrum, UV-Visspectrum and J-V curve. The research contents are as follows:1. The two news of new3-D conjugated polymer with the bridge chains ofbenzothiadiazole PH-1and PH-2were designed and synthesized. The influence ofdifferent electronic donor units of the polymer on thermal stability, light physical,electrochemical, and photovoltaic performance was investigated. The results showedthat the stronger electron-donating ability had the lower HOMO energy level of thepolymer, and its photovoltaic performance had improved simultaneously. Powerconversion efficiency based on three-dimensional conjugate copolymer ofPH-2/PC61BM bulk heterojunction section of the solar cell device reached2.06%.2. Through a series of organic reactions, such as Vilsmeier-Haack reaction,Wittig-Horner reaction, Stille coupling reaction and Suzuki coupling reaction, twonew triphenylamine derivatives TPA-DTBT and DH–2were synthesized, and theirstructures had been characterized by mass spectrum, infrared spectrum and nuclearmagnetic resonance （NMR） spectrum. Two small molecular with the benzothiadiazolebridge chain used for bulk heterojunction and dye sensitized solar cell devicesrespectively. Under the condition of simulated sunlight, the power energy conversionefficiency of the small molecule bulk heterojunction solar cell device based on TPA-DTBT reached2.79%(V_oc=0.85V, Jsc=9.46mA/cm², FF=0.347); the energyconversion efficiency of the dye sensitized solar cell device based on DH-2reached1.67%(V_oc=0.55V, Jsc=4.23mA/cm², FF=0.72).