High-performance organic solar cells by adding the third component

Organic solar cells have attracted much attention over the past decades, which have numerous advantages, including solution-processability, low cost, light weight, and flexibility. Due to the development of non-fullerene acceptors, the efficiencies of organic solar cells were increased to 17% for a tandem junction and 14% for a single junction. To further improve the efficiency of organic solar cells, a third component can be added to the active layer making a ternary blend film. Ternary blend film contains a donor material, an acceptor material, and a third component having complimentary absorption with the donor and acceptor, increasing the light harvesting ability of the devices. Some of the third components have suitable energy levels to reduce the charge transfer barriers between the donor and acceptor. The added component can also induce the crystallization of the donors and change the morphology of the blend film. In our work, a few third components were selected to add in the active layer, which leads to an improvement of the device performance. Also, the absorption, charge transportation and the morphology of the ternary system were carefully investigated to understand how the third component influences the efficiency of organic solar cells.