Petra Pavlačková

Low-Band Gap Donor-Acceptor Copolymers Containing Thienothiadiazole Units for Photovoltaics

Polythiophenes and thiophene-containing polymers have extensively studied due to their potential applications in photovoltaics [1-4]. Polymers with broad absorption up to longer wavelengths are required to improve harvesting of the terrestrial solar radiation. Therefore, great deal of attention is focused on synthesis and characterization of novel low-band gap polymers. To the date copolymerization of an electron-donor (D) and electronacceptor (A) monomers is the most successful strategy how to achieve low-band gap polymers. Fine tuning of the bandgap is enabled by a choice of building blocks due to the intrachain charge transfer (ICT) from the donor to the acceptor moiety. In this contribution, we deal with optical, spectroelectrochemical and photovoltaic properties of novel donor-acceptor copolymers containing thienothiadiazole units (see Figure 1). We used 4,6-di(2thienyl)thieno[3,4-c][1,2,5]thiadiazole as an interesting building block due to its extended absorption at long wavelengths and the electron-acceptor nature of its central thienothiadiazole moiety.