Synthesis and Study of Janus-Dione-Based Compounds for Ternary Organic Solar Cells

The efficiency of organic solar cells is constantly improving thanks to more advanced materials. Electron donor polymers, such as <b>PM6</b> and its derivatives, as well as non-fullerene acceptors (NFAs) <b>Y6</b> and <b>ITIC</b> and their derivatives, have become the standard materials for organic solar cell studies. To broaden the absorption range of solar cells, so-called ternary organic solar cells have been developed, which add a third material to the active layer. In this work, two chromophores based on the derivatives of the Janus-dione (<i>s</i>-indacene-1,3,5,7(2<i>H</i>,6<i>H</i>)-tetraone) central acceptor fragment, namely <b>TIIC-1</b> and <b>TIIC-2</b>, were synthesized. Materials were characterized using theoretical and experimental methods, including UV-Vis absorption measurements, cyclic voltammetry, photoemission yield spectroscopy, and photoconductivity. The materials were incorporated as ternary components in <b>PM6:Y7</b> bulk heterojunction solar cells. The power conversion efficiency (PCE) of <b>PM6:Y7:TIIC-1</b> ternary solar cells was improved compared to binary <b>PM6:Y7</b> reference cells. The PCE increased from 11.9% in binary blends to 12.5% in ternary cells. This increase is attributed to the cascade-like energy level arrangement, which facilitates charge transfer in the photoactive layer.