Copolymers Comprising Benzodithiophene and Benzotriazole Derivatives for Organic Solar Cells


Tezin Türü: Yüksek Lisans

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

Tezin Onay Tarihi: 2016

Öğrenci: Duygu Güven

Asıl Danışman (Eş Danışmanlı Tezler İçin): ALİ ÇIRPAN

Özet:

In recent years, converting different energy sources into electricity is under massive investigation. Sun light is an environmental source having a great potential to be utilized as a green energy source. The photovoltaic cells directly convert sun light into electricity. In this study, organic photovoltaic cells in which an active material absorbing sun light and generating electricity were examined. For this aim, two novel organic conjugated polymers were synthesized. Benzodithiophene moiety was used as a donor unit and benzotriazole unit functionalized by alkyl chain was selected as an acceptor unit. Selenophene and thiophene groups were used as -bridge with their donor character. In this manner, two different conjugated polymers were synthesized via Stille coupling reaction. The electrochromic and photovoltaic properties of the polymers were studied. Average molecular weights of synthesized polymers were calculated by gel permeation chromatography. Cyclic voltammetry was used to investigate redox behaviors and UV-Vis spectrophotometer was used to determine optical properties of polymers. Electronic band gap values of P-SBTBDTT and P-TBTBDTT were found as 1.96 eV and 2.2 eV, respectively. On the other hand, optical band gap values were obtained as 1.87 eV and 1.95 eV for P-SBTBDTT and P-TBTBDTT, sequentially. In photovoltaic studies, device fabrication was carried out in a moisture free glove box. Devices were constructed by using ITO coated glass substrate covered by different ratios of polymer:PC71BM layers. Consequently, the highest power conversion efficiency was found as 1.50 % for P-TBTBDTT under standard AM 1.5 G illumination (100 mW/cm2) in the preliminary studies.