Functionality of Non-Fullerene Electron Acceptors in Ternary Organic Solar Cells

Ternary organic solar cells, a single active layer comprising three different components, are demonstrated to be one of the most efficient ways to approach high-performance organic solar cells. But nevertheless, most of the ternary organic solar cells are characterized by steady-state measurements, which are helpful but inadequate to fully understand the underlying charge carrier behavior at a short time scale. Herein, a comparison of the steady-state and time-dependent measurements is used to investigate the functionality of non-fullerene electron acceptors in ternary organic solar cells. The steady-state measurements indicate that non-fullerene electron acceptors enlarge the absorption range of the photoactive layer, suppress charge carrier recombination, reduce charge carrier transfer resistance, and thereby increase photocurrent in ternary organic solar cells. The time-dependent measurements demonstrate that a short charge carrier extraction time and a high charge carrier mobility are responsible for enhanced photocurrent in ternary organic solar cells. A comprehensive method understanding the underlying of enhanced efficiency of ternary organic solar cells is provided herein.