The global energy demand is increasing constantly and the primary source of energy is fossil fuels which are not environmentally friendly because of the substantial amount of carbon dioxide emission. For that and many other reasons it is necessary to use alternative energy resources. Solar energy is an important source of renewable energy. Interests in organic-based photovoltaic devices (OPVs) have emerged due to the many promising organic semiconductors. For better organic solar cell efficiency, the organic material must fulfill some requirements: the material must be made of organic conjugated molecules, the energy difference between the HOMO and LUMO of the material must be small and the molecule must be planar. In this project, conjugated small molecules based on 2,1,3-benzothiadiazole and 2,1,3-benzoxadiazole as acceptors were synthesized. The novel molecules have a Donor-Acceptor-Donor arrangement in which the donor units are composed of the novel 2-(2-Thienyl-3-dodecyl)-1-benzofuran. The optical and electrochemical properties of these compounds were determined by UV/Vis spectroscopy and cyclic voltammetry (CV). The efficiencies of these materials in OPVs were determined using the Process Cycle Efficiency (PCE) Formula. The study showed that there is an advantage in using 2,1,3-benzoxadiazole as an acceptor moiety instead of 2,1,3-benzothiadiazole and suggested that materials with 2,1,3-benzoxadiazole are more effective donors for OPVs than materials with 2,1,3-benzothiadiazole. The power conversion efficiency of the best performing OPV was 3.67% with devices containing the benzoxadiazole based material showing high open-circuit voltage.

Synthesis of novel conjugated small molecules based on 2,1,3-benzothiadiazole and 2,1,3-benzoxadiazole for organic photovoltaic applications

253rd National Meeting (2017)

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