Syntheses and Optoelectronic Applications Of Thiadiazolo Quinoxaline Bearing Alternating Conjugated Copolymers

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2016

Öğrenci: Emre Ataoğlu

Asıl Danışman (Eş Danışmanlı Tezler İçin): ALİ ÇIRPAN

Eş Danışman: HÜSNÜ EMRAH ÜNALAN

Özet:

Donor-acceptor type conjugated polymers containing thiadiazolo quinoxaline and benzodithiophene derivatives were used as photoactive material for organic solar cell. The alkoxy- substituted benzo[1,2-b;4,5-b’]dithiophene (BDT) monomer, 2,6bis(trimethyltin)-4,8-di(2-ethylhexyloxyl)benzo[1,2-b;4,5-b’]dithiophene, was polymerized with 4,9-dibromo-[1,2,5]thiadiazolo[3,4-g]quinoxaline through a Pd(0)catalyzed Stille coupling reaction. In order to improve the interchain interactions between polymer chains, an alkylthiophene-substituted BDT derivative was synthesized and polymerized with identical counter monomer. Chemically synthesized polymers were characterized by 1H NMR, GPC, TGA and DSC. Electrochromic studies showed that polymers have similar multichromic properties. Both polymers have ocher color in their neutral states and grey color in their oxidized states. The lowest switching times obtained for both polymers were 0.9 s (975 nm) for P1 and 1.0 s (425 nm) for P2. Optical band gap energies of P1 and P2 measured as 1.04 eV and 1.10 eV, respectively. Photovoltaic properties of the copolymers mixed [6,6]-phenyl C71 –butyric acid methyl ester (PC71BM), were investigated. P2 exhibited the best device performance with an open circuit voltage of 0.52 V, short circuit current of 2.82 mA/cm2 and power conversion efficiency of 0.73 % under Airmass 1.5 Global (AM1.5G, 100 mW/cm2) illumination.