Status and prospects for ternary organic photovoltaics

In the past few years, ternary organic solar cells (OSCs) featuring multiple donor or acceptor materials in the active layer have emerged as a promising structure to simultaneously improve all solar cell parameters compared with traditional binary OSCs. Power conversion efficiencies around 10% have been achieved for conjugated polymers in a ternary structure, showing the great potential of ternary systems. In this review, we summarize progress in developing ternary OSCs and discuss many of the designs, chemistries and mechanisms that have been investigated. We conclude by highlighting the challenges and future directions for further development in the field of ternary blend OSCs.