Oligomerized Fused‐Ring Electron Acceptors for Efficient and Stable Organic Solar Cells

Abstract

Organic solar cells (OSCs) have attracted wide research attention in the past decades. Very recently, oligomerized fused‐ring electron acceptors (OFREAs) have emerged as a promising alternative to small‐molecular/polymeric acceptor‐based OSCs due to their unique advantages such as well‐defined structures, batch reproducibility, good film formation, low diffusion coefficient, and excellent stability. So far, rapid advances have been made in the development of OFREAs consisting of directly/rigidly/flexibly linked oligomers and fused ones. In this Minireview, we systematically summarized the recent research progress of OFREAs, including structural diversity, synthesis approach, molecular conformation and packing, and long‐term stability. Finally, we conclude with future perspectives on the challenges to be addressed and potential research directions. We believe that this Minireview will encourage the development of novel OFREAs for OSC applications.

Over 18% Efficiency Ternary Organic Solar Cells with 300 nm Thick Active Layer Enabled by an Oligomeric Acceptor

“…Thus, OSCs with long-term stability have been constructed by employing the oligomers. [52,53] The chosen third component, an oligomeric electron acceptor (DY-TF) possesses a highly fused and co-planar structure, resulting in a high glass transition temperature (T g ) (231 °C), beneficial to the stability of the film morphology. [54] The T g of PM6:DY-TF film was determined to be 273 °C.…”

Synthesis of Long‐Chain Oligomeric Donor and Acceptors via Direct Arylation for Organic Solar Cells†

“…Up till now, polymers and small molecules are two kinds of typical materials used in OSCs, their oligomeric counterparts, however, have received much less attention. [ 36‐45 ] Actually, monodisperse ( Ɖ = 1.0) π‐conjugated oligomers (π‐CO), as mediate bridges between small molecules and polymers, are expected to simultaneously combine the advantages of the defined structures of molecules, and the high light/thermal stability of polymers, owing to their moderately elongated backbones. [ 40‐41 ] Zhan et al .…”

“…[ 36‐45 ] Actually, monodisperse ( Ɖ = 1.0) π‐conjugated oligomers (π‐CO), as mediate bridges between small molecules and polymers, are expected to simultaneously combine the advantages of the defined structures of molecules, and the high light/thermal stability of polymers, owing to their moderately elongated backbones. [ 40‐41 ] Zhan et al . synthesized a series of FREA‐based oligomers F5IC, F6IC, F7IC, F8IC, F9IC, F10IC and F11IC containing 5 to 11 rings with gradual extension of polycyclic cores, [ 42‐43 ] of which the dependence of OSC performances on the π‐conjugation lengths was systematically investigated.…”

Tethered Small‐Molecule Acceptor Refines Hierarchical Morphology in Ternary Polymer Solar Cells: Enhanced Stability and 19% Efficiency

“…These discrete materials are referred to as quasi-PSMAs, oligomers, "A-𝜋-A," or "N-𝜋-N" acceptors in reports. [24][25][26][27][28][29][30][31] Recently, they have been defined as giant molecule acceptors (GMAs) by Li, [32] emphasizing their distinct advantages, such as extended molecular sizes for higher T g values relative to their constituent SMAs and stronger intermolecular assembly aggregations compared to parent PSMAs.…”