Synthesis and characterization of new dyes based on chromone malononitrile as the electron withdrawing group and their photovoltaic effect

Abstract

Two new small molecule dyes for the donor material, named IDTT-OX and IDTT-EPMP-IDC have been successfully synthesized and characterized for solution-processed bulk heterojunction organic solar cells (OSCs). These dyes are containing indacedithieno[3,2-b]thiophene (IDTT) as the donor moiety, phenylisoxazolone (OX) and malononitrile derivatives (EPMP-IDC) as the acceptor. IDTT-OX exhibits a strong self-aggregation behavior and broad absorption with an optical band gap of 1.88 eV. While IDTT-EPMP-IDC shows different behavior, the self-aggregation of IDTT-EPMP was efficiently restricted by the presence of the alkyl group at EPMP-IDC functional group in the molecule and it has 1.60 eV optical bandgap. The inverted-type OSCs based on the blend of IDTT-OX (or IDTT-EPMP-IDC) as a donor, PC₇₁BM as an acceptor are fabricated. The power conversion efficiencies (PCEs) of the optimized OSCs are reached up to 0.29% for IDTT-OX and 2.07% for IDTT-EPMP-IDC.

Keywords:

• Indacenodithienothiophene-based photoactive material
• inverted organic solar cell
• small molecule donor

Additional information

Funding

This work was supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. 20194010201840) and was supported by the BB21+ Project in 2019.