Effect of Arylmethylene Substitutions on Molecular Structure, Optoelectronic Properties and Photovoltaic Performance of Dithienocyclopentafluorene‐Based Small‐Molecule Acceptors

Abstract

Two dithienocyclopentafluorene-based small-molecule acceptors (SMAs) were developed that feature methylene-functionalized conjugated side chains, to study the effect of arylmethylene substitution and its number on structure, optoelectronic properties and device performance. Results showed that two SMAs have better absorption properties and planarity, lower bandgaps and higher LUMOs compared with the control SMA without conjugated side chains. The synthesized SMAs were tested in polymer solar cells for examples of their applicability. This work argues that the introduction of methylene-functionalized conjugated side chains has great potential in tuning molecular structure, optoelectronic properties, device physics and photovoltaic performance of SMAs.

Improving the Photovoltaic Performance of PBDB-T:PC71BM-Based Ternary Solar Cells by Employing Arylmethylene-Substituted Small Molecules as the Guest Acceptor

“…According to the above photovoltaic performance results, we first can find that these four SMAs display quite different device performances in the guest binary PSCs, as shown in Tables S2–S5. The obtained efficiencies of the binary PSCs based on these four acceptors were 0.44%, 0.42%, 5.85%, and 8.14% for PBDB-T: IDTV-SiIC , PBDB-T: IDTVT-PhIC , PBDB-T: m-IDTV-PhIC , and PBDB-T: DTCFDV-IC , respectively. In view of the very poor efficiency, we did not further optimize the photovoltaic performances of the first two acceptors.…”

“… a Measured in a thin film; listed in parentheses as shoulder peaks. b Absorption edge of the thin films. c Estimated from the absorption edge of the absorption spectra: E g opt = 1240/λ edge . d Gained from CV measurement based on the equation HOMO/LUMO = − e ( E ox/red + 4.34) (eV). e The data came from ref . f The data came from ref . …”

“…Previously, our group developed a kind of efficient SMA featuring methylene C-functionalized conjugated side chains, such as m-IDTV-PhIC and DTCFDV-IC . The binary PSCs based on these kinds of SMAs exhibited increased PCEs relative to the similar SMAs without conjugated side chains due to the improved V oc and J sc , which is attributed to the upshifted LUMO energy levels and improved absorption properties after the introduction of arylmethylene-conjugated side chains .…”

Molecular engineering of N,S-heteroarene-based small-molecule acceptors: effects of side chains, backbone extension and end groups on structure, optoelectronic properties and solar cell performance

“…pyrrole, see Y6); and (iv) by introducing aryl-substituted methylene group into the cyclopentadiene moiety. 22,23…”

“…pyrrole, see Y6); and (iv) by introducing arylsubstituted methylene group into the cyclopentadiene moiety. 22,23 The ring-fused D unit is commonly constructed from polycyclic heteroarenes containing a benzene ring and thiophene, 13 for example, heptacyclic indacenodithienothiophene (IDTT) in ITIC. 1 Besides, for Y-series SMAs, the ring-fused central core is formed by fusing an electron-deficient unit A 0 (e.g.…”