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Investigation of optoelectronic properties of benzotriazole and thiazole bearing conjugated polymers

Ünay, Hakan
This thesis deals with the design, synthesis and characterization of conjugated polymers P1 and P2 that have potential application in organic solar cell. Polymer design was accomplished by using band gap engineering method. According to that, benzodithiophene (BDT) and silafluorene were chosen as donor groups in P1 and P2 respectively. The acceptor parts were the same for both polymers including benzotriazole (BTZ) and thiazole group. According to electrochemical studies both polymers were having n-dopable and p-dopable characters. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of P1 were determined as -5.63 eV and -3.60 eV, while P2 had HOMO and LUMO energy levels -6.00 eV and -3.58 eV respectively. Optical band gap of P1 and P2 were calculated as 2.10 eV and 1.74 eV accordingly. Device construction was carried out with Bulk Heterojunction method and PCBM was used as the acceptor due to its suitable acceptor properties in polymeric solar cell applications. The best PCE was obtained from the device containing P1/PCBM 1:4 (w/w) ratio as 0.45 % under standard AM 1.5 G at 100 mW/cm2.