Organik güneş pili uygulamaları için benzo[c][1,2,5]okzadiyazol içeren konjüge polimerlerin sentezi, karakterizasyonu ve fotovoltaik özellikleri

In this thesis, six conjugated polymers were synthesized by coupling of 2,1,3-benzoxadiazole derivatives with donor groups via Stille polycondensation reactions. Moreover, the effect of molecular weight for P1 and P2, effect of position of alkyl chain for P5 and effect of π-bridge groups for P6 which are selenophene and thiophene on optical, electrochemical, and photovoltaic properties were investigated. Also, modifications on alkyl chains of P3 and P4 were performed to increase their functionalities via post-polymerization reactions. Electronic and optical band gaps of polymers were found as 1.83/1.81, 1.86/1.76, 2.03/1.74, 2.07/1.74, 1.76/1.72, and 2.10/1.71 respectively for P1, P2, P3, P4, P5, and P6. Furthermore, the effect of the addition of gold nanoparticles to the active layer of organic solar cells on photovoltaic properties was analyzed. Synthesized polymers were characterized by infrared (IR) spectroscopy, gel permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimeter (DSC) and UV-Vis-NIR spectroscopy. Redox behaviors and electronic band gaps of polymers were investigated by the cyclic voltammetry (CV) method. Device production and current/voltage property measurements were carried out in a nitrogen-filled glovebox system. While PC71BM was the acceptor unit, synthesized polymers were donor units for the conventional type device structure of ITO/PEDOT:PSS/polymer:PC71BM/LiF/Al. Photovoltaic properties of constructed devices were measured under 100 mW cm-2 illumination (standard illumination of AM 1.5 G). Best device performances were found as 10.33% for P1, 6.43% for P2 and, 1.63% for P5. The optimization process is still in progress for P3, P4, and P6.