Unconventional third components for ternary organic solar cells

The ternary organic solar cells (TOSCs) have recently emerged as an efficient strategy to effectively overcome the shortcomings of the binary bulk heterojunction (BHJ) devices, by enabling stronger and broader photo-absorption and efficient nanomorphology regulation, which in turn leads to better charge generation, transportation, and collection in the corresponding devices. Hence, power conversion efficiencies (PCEs) over 17% have been successfully achieved by a careful inclusion of an appropriate ternary component in the binary films. Pursuing even higher PCEs, the researchers have even utilized various untraditional organic conjugated molecules or other nanomaterials as the third component to enhance their device performance. Therefore, in this review, besides describing the role of the traditional ternary components, the use of various unconventional third components, such as organic dyes, solid additives, nanomaterials, and quantum dots, etc., to enhance the absorption range, crystallinity, phase separation, and charge mobility, etc., and ultimately, the performance of the ternary devices, have been summarized.