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Extended Conjugation Length of Nonfullerene Acceptors with Improved Planarity via Noncovalent Interactions for High‐Performance Organic Solar Cells
Author(s) -
Liu Dongxue,
Kan Bin,
Ke Xin,
Zheng Nan,
Xie Zengqi,
Lu Di,
Liu Yongsheng
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201801618
Subject(s) - organic solar cell , planarity testing , materials science , intramolecular force , conjugated system , band gap , non covalent interactions , acceptor , homo/lumo , thiophene , small molecule , polymer solar cell , photochemistry , energy conversion efficiency , optoelectronics , nanotechnology , molecule , polymer , crystallography , chemistry , stereochemistry , hydrogen bond , physics , organic chemistry , biochemistry , composite material , condensed matter physics
Three low‐bandgap nonfullerene acceptors (NFAs) IDTO‐T‐4F, IDTO‐Se‐4F, and IDTO‐TT‐4F with extended conjugation length are designed and synthesized. Various π‐spacers, thiophene, selenophene, and thieno[3,2‐ b ]thiophene are incorporated to extend the conjugated length and enhance the backbone planarity via noncovalent O···S or O···Se interactions. These NFAs exhibit strong light absorption in the range of 600–900 nm with narrow bandgaps between 1.38 and 1.45 eV. By blending with a wide‐bandgap donor material PBDB‐T, organic solar cells (OSCs) based on these NFAs all yield high efficiency over 10% with low energy losses ranging from 0.52 to 0.59 eV. Importantly, as a result of relatively high lowest unoccupied molecular orbital level, large hole and electron mobility in blend film, and low charge carrier recombination loss, optimized devices based on IDTO‐T‐4F exhibit a large open‐circuit voltage of 0.864 V, a high short‐circuit current density of 20.12 mA cm −2 , and a notable fill factor of 72.7%, leading to an impressive efficiency of 12.62%, which represents the best performance for NFA OSCs using noncovalent interactions in acceptor molecule design. The results indicate that optimizing the conjugation length and backbone planarity via intramolecular noncovalent O···S or O···Se interactions is a useful strategy for NFA materials invention toward high‐performance solar cells.