Syntheses, spectroelectrochemical and electrochemical characterizations of naphthodithiophene containing polymers for solar cell applications

Işık, Ebru
Naphthodithiophene is a thiophene fused naphthalene with a rigid and planar structure with extended π-conjugation system. Due its electron rich nature it has been recently employed in donor-acceptor type conducting polymers which are used as active layers in organic solar cells and organic field effect transistors. In this study alkoxy functionalized naphthodithiophene bearing two new random copolymers were designed and synthesized. As acceptor moiety in the polymer backbone electron deficient benzotriazole moiety was used. Thiophene and bithiophene units were used as π-linkers to enhance electron delocalization through polymer chain. Polymers were synthesized via Stille polycondensation reaction. Investigation of optoelectronic properties of synthesized polymers were performed with cyclic voltammetry and spectroelectrochemistry studies. Moreover, colorimetric and kinetic properties of the polymers were examined. From thiophene bridge to bithiophene bridge improvements in the properties of polymers were observed. Synthesized polymers were used as donor in bulk heterojunction organic solar cell applications together with PC71BM acceptor. Polymer bearing bithiophene as π-bridge demonstrated 1.17% maximum power conversion efficiency.