| Along with the traditional energies dried up, the development and utilization of new energy are problems which is needed to solve urgently. In recent years polymer solar cells have become a researchful hot spot because it have many advantages that other solar cells don’t have. But low power conversion efficiency is an important factor which restricts the development of the polymer solar cells’ application. Therefore, research workers are studying to explore in the design of new materials, the optimization of the preparation process and the improvement of organic light activated layers’ morphology. The researchers are dedicated to studying the high efficiency solar cells. One of the most feasible methods is to design and synthetize the high performance polymer donor materials.In this paper, the electro-donating units which have large conjugate surfaces and length: 5,10-bis(triisopropylsilyethynyl)dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene(DTBD T-TIPS) and 5,10-bis(4,5-didecylthiophene)dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene(TE) have been synthetized. Several copolymers have been synthesized by Stille coupling, the DTBDT derivatives are used as electro-donating part and other materials as electro-accepting units, and the polymers’ structure and the photovoltaic performance is characterized by professional equipments.In chapter 2, the electro-donating monomer of 2,7-di(trimethylstannyi)-5,10-bis(triisopropylsilyethynyl)dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b′]dithiophene(DTBDTSn-TIPS) and the electro-accepting monomer of 6,6′-dibromo-N,N′-di(2-hexyldecyl)isoindigo(ID-HD) react with each other by Stille coupling in order to obtain the copolymer PDTBDT-TIPS-IDHD, and the polymer’s thermostability is better. The polymer is soluble in organic solvents such as toluene, chlorobenzene. The polymer’s optical band gap is 1.56 eV, EHOMO and ELUMO are﹣5.43 eV and ﹣3.87 eV, respectively. The device is made by using PDTBDT-TIPS-IDHD as donor material and PC61 BM as acceptor material, the highest power conversion efficiency is 2.92%(VOC = 0.88 V,JSC = 7.32 mA/cm2,FF = 45.28%).In chapter 3, the copolymer PDTBDT-TIPS-BTZDT is got by the reacting of DTBDTSn-TIPS and 4,7-dibromo-2-(2-decyltetradecyl)-2H-benzo[d][1,2,3]triazole(BTZDT). The polymer PDTBDT-TIPS-BTZDT had good thermal stability and solubility. Its absorption band edge is 673 nm in thin film. The polymer’s Eg, onset potential and HOMO energy level are 1.84 eV, 0.73 V and ﹣ 5.46 eV, respectively. The device is made by using PDTBDT-TIPS-BTZDT as donor material and PC61 BM as acceptor material, the highest power conversion efficiency is 1.65%(VOC = 0.98 V,JSC = 3.75 mA/cm2,FF = 44.97%).In chapter 4, the copolymer PTE-DTNTC8 is obtained by the Stille coupling reaction by using 2,7-di(trimethylstannyi)-5,10-bis(4,5-didecylthiophene)dithieno[2,3-d:2′,3′-d′]benzo [1,2-b:4,5-b′]dithiophene(TESn) as electro-donating unit and 3,7-di(2-bromo-3-octylthiophene-5-yl)-naphtho[1,2-c:5,6-c′]-bis[1,2,5]thiadiazole(DTNTC8Br) as electro-accepting, and characterize the structure and photovoltaic performance of the polymer. The two polymer’s absorption peaks of PTE-DTNTC8 appear at 415 nm and 643 nm both in toluene solution and thin film. Its absorption band edge is 791 nm in thin film and the Eg is 1.57 eV. The polymer PTE-DTNTC8 has good thermal stability and lower HOMO energy level(EHOMO = ﹣5.23 eV). The device is made by donor material and acceptor material PC61 BM. The power conversion efficiency of the device is 3.06%(VOC = 0.64 V,JSC = 8.67mA/cm2,FF = 55.09%). |
PDF Full Text Request