ИСТИНА

Bulk heterojunction organic solar cells have attracted attention due to their light weight, low cost, and flexibility. Donor-acceptor (D-A) conjugated polymers have been widely employed as active layer components in organic solar cells because of their tunable band gap, frontier energy levels and charge transport characteristics. It has been shown recently that (X-DADAD)n type polymers demonstrate improved optoelectronic characteristics compared to conventional (X-DAD)n type structures. In this work, we synthesized and investigated a novel polymer P1 with 1,4-bis((2-hexyldecyl)oxy)benzene (X), benzothiadiazole(A) and thiophene(D) units. Polymer P1 demonstrated strong self-assembling and intermolecular interactions in solid state as can be concluded from a spectacular red shift of its absorption band while going from solution to thin films. P1 has reasonably low band gap (Egopt) of ~1.6 eV and HOMO energy of -5.3 eV, as estimated from the absorption onset and electrochemical measurements. Organic solar cells based on P1/[60]PCBM have been fabricated and their photovoltaic characteristics explored. The devices showed power conversion efficiencies of ⁓ 4% with short-circuit current densities of 10.2 mA cm-2, open-circuit voltages of 587 mV, and fill factors of 63%. We believe that further optimization of the polymer structure and methodology of the solar cells fabrication will allow us to reach better device performance. This work was supported by RFBR (project № 18-33-00667).