Fluorinated Head‐to‐Head Dialkoxybithiophene: A New Electron‐Donating Building Block for High‐Performance Polymer Semiconductors

Abstract

New building blocks with good solubility and optimized optoelectrical property are critical for materials development in organic electronics. Herein, a new head‐to‐head linkage containing a donor unit, 4,4′‐difluoro‐3,3′‐dialkoxy‐2,2′‐bithiophene (BTfOR), is synthesized. The dialkoxy chains afford good materials solubility and also planar backbone via noncovalent (thienyl)S⋯(alkoxy)O interactions. Compared to the reported 3,3′‐dialkoxy‐2,2′‐bithiophene (BTOR), F addition leads to BTfOR with lower‐lying frontier molecular orbitals and can further promote polymer packing via additional F⋯S or F⋯H interactions. BTfOR can be readily stannylated to afford tin monomer with high purity and excellent reactivity toward Stille polymerization. As a proof of concept for materials design, BTfOR‐based homopolymer (PBTfOR) is synthesized, showing high molecular weight and strong aggregation. Moreover, the HOMO (−4.98 eV) of PBTfOR is greatly lower than that (−4.54 eV) of nonfluorinated counterpart PBTOR, which is attributed to the addition of F atoms. When incorporated into thin‐film transistors, PBTfOR exhibits a remarkable hole mobility of 0.57 cm2 V−1 s−1, showing an exceptional example of high‐mobility head‐to‐head polythiophene. This study demonstrates that introduction of F atoms can lead to BTfOR with optimized physicochemical properties, and the new BTfOR should find promising use for constructing donor–acceptor copolymers for high‐performance electronic devices.

Molecular Engineering and Morphology Control of Polythiophene:Nonfullerene Acceptor Blends for High‐Performance Solar Cells

“…Attaching electronwithdrawing groups onto the thiophene unit has been a commonly used method to construct PTs with downshifted energy levels. [52][53][54][55][56][57][58] Besides, the enhancement of V oc of PT-based OPVs can also be achieved by designing nonfullerene acceptors with high LUMO energy levels. In this section, we discuss PTs with various electron-withdrawing groups and the main classes of nonfullerene acceptors paired with P3HT, and importantly relate their device performance to the key structural factors of the materials.…”

Heteroalkyl‐Substitution in Molecular Organic Semiconductors: Chalcogen Effect on Crystallography, Conformational Lock, and Charge Transport

“…Thus, the derived E HOMO of 5 is estimated at −4.79 eV, which should result in an easily p‐dopable semiconductor. [ 58 ] Thus this data, which are recorded in solution, suggests that ‐SR and ‐SeR minimally affects the HOMO energies while the LUMO energies are more affected; on the contrary ‐OR strongly affects both molecular orbital energetics. Note, to access the stability of the redox processes and oxidized species, we carried out cyclic voltammetry experiments for the compounds DDTT‐SeBT ( 1 ), DDTT‐SBT ( 4 ), and DDTT‐OBT ( 5 ) (Figure S5, Supporting Information).…”

Engineering of the alkyl chain branching point on a lactone polymer donor yields 17.81% efficiency

“…46 The "edge-on/face-on" bimodal packing was found in some CPs. [47][48][49][50][51][52][53] It is a favorable packing mode for OSCs since it facilitates both lateral and vertical charge transport. 51,54 The p-p stacking and lamellar stacking dspacings estimated from the q values of the (010) and (100) peaks are 3.74 Å and 19.55 Å for L2, and 3.74 Å and 20.77 Å for L3, respectively (Table S1 †).…”