Synthesis Of Bistriphenylamine And Benzodithiophene Based Random Conjugated Polymers For Organic Photovoltaic Applications


Tezin Türü: Yüksek Lisans

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

Tezin Onay Tarihi: 2018

Öğrenci: Aslı Çetin

Asıl Danışman (Eş Danışmanlı Tezler İçin): ALİ ÇIRPAN

Özet:

Nowadays, traditional fossil fuels have become unable to compensate huge energy demand of the world due to the population increasing day by day and bringing about destructive greenhouse effect. Owing to all of these problems, renewable energy sources such as solar energy not only can be candidate for the solution of this expanded energy need but also can protect the earth by reducing the production of greenhouse gas. In this study, electronic, optical features and photovoltaic applications of two novel organic materials have been investigated to improve photovoltaic researches. With this aim, derivatives of bistriphenylamine, benzodithiophene as donor units and benzotriazole as an acceptor unit containing donor/acceptor (D/A) type random conjugated polymers, P1 & P2, have been synthesized via Stille coupling reaction. The structure and the average molecular weight of these polymers have been examined with nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC), respectively. Electrochemical characterizations of the polymers were investigated with cyclic voltammetry and also, UV-Vis-NIR spectrophotometer was used to determine optical features of the polymers. Electronic and optical band gaps of the polymers were recorded as 2.06 eV, 2.16 eV for P1 and 2.16 eV, 2.11 eV for P2, respectively. In order to determine photovoltaic properties of vi the polymers device fabrications were constructed with ITO coated glass substrate, PEDOT:PSS, (P1 or P2):PC71BM, LiF and Al in a given order. Photovoltaic performance of these polymer solar cell devices were measured under AM 1.5G solar irritation of solar simulator via Keithler 2400 source meter. Photovoltaic studies showed that the highest power conversion efficiency (PCE) of these photovoltaic devices were recorded as 3.50 % with open circuit voltage; 0.79 V, short circuit current; 9.45 mA cm-2, fill factor; 0.53 % for P1:PC71BM (1:2, w/w) in 3 % o-dichlorobenzene (o-DCB) solution and 3.15 % with open circuit voltage; 0.75 V, short circuit current; 8.59 mA cm-2, fill factor; 0.49 % for P2:PC71BM (1:2, w/w) in 2% chlorobenzene (CB) solution.