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

## TL;DR

Researchers synthesized new Janus-dione-based compounds to improve the efficiency of organic solar cells by adding them as a third component.

## Contribution

The synthesis and characterization of TIIC-1 and TIIC-2 as ternary components for organic solar cells is the novel contribution.

## Key findings

- Adding TIIC-1 to PM6:Y7 solar cells increased power conversion efficiency from 11.9% to 12.5%.
- The efficiency gain is due to a cascade-like energy level arrangement that enhances charge transfer.

## Abstract

The efficiency of organic solar cells is constantly improving thanks to more advanced materials. Electron donor polymers, such as PM6 and its derivatives, as well as non-fullerene acceptors (NFAs) Y6 and ITIC 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 (s-indacene-1,3,5,7(2H,6H)-tetraone) central acceptor fragment, namely TIIC-1 and TIIC-2, 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 PM6:Y7 bulk heterojunction solar cells. The power conversion efficiency (PCE) of PM6:Y7:TIIC-1 ternary solar cells was improved compared to binary PM6:Y7 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.