Chemistry

Materials science

Optoelectronics

Engineering

Composite material

Side chain

Biochemistry

Physics

Small molecule

Work (physics)

Dipole

Organic chemistry

Energy conversion efficiency

Organic solar cell

Astronomy

Acceptor

Polar

Molecule

Photovoltaic system

Polymer solar cell

Electrical engineering

Condensed matter physics

Polymer

Thermodynamics

Advanced Materials

In this work, an effectual strategy of constructing polar small molecule acceptors (SMAs) to promote fill factor (FF) of nonfullerene polymer solar cells (PSCs) is first reported. Three asymmetrical SMAs of IDT6CN, IDT6CN-Th, and IDT6CN-M, which own large dipole moments, are designed and synthesized. The PSCs based on three polar SMAs exhibit apparently higher FFs compared with their symmetrical analogues. The asymmetrical design strategy accompanied with side chain and end group engineering makes IDT6CN-Th- and IDT6CN-M-based nonfullerene PSCs achieve high power conversion efficiency with FFs approaching 77%.

Asymmetrical Ladder‐Type Donor‐Induced Polar Small Molecule Acceptor to Promote Fill Factors Approaching 77% for High‐Performance Nonfullerene Polymer Solar Cells