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Metal–Ligand Based Mechanophores Enhance Both Mechanical Robustness and Electronic Performance of Polymer Semiconductors
Author(s) -
Wu HungChin,
Lissel Franziska,
Wang GingJi Nathan,
Koshy David M.,
Nikzad Shayla,
Yan Hongping,
Xu Jie,
Luo Shaochuan,
Matsuhisa Naoji,
Cheng Yuan,
Wang Fan,
Ji Baohua,
Li Dechang,
Chen WenChang,
Xue Gi,
Bao Zhenan
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202009201
Subject(s) - materials science , thiophene , polymer , semiconductor , electron mobility , chemical engineering , nanotechnology , crystallography , optoelectronics , organic chemistry , composite material , chemistry , engineering
The backbone of diketopyrrolopyrrole‐thiophene‐vinylene‐thiophene‐based polymer semiconductors (PSCs) is modified with pyridine (Py) or bipyridine ligands to complex Fe(II) metal centers, allowing the metal–ligand complexes to act as mechanophores and dynamically crosslink the polymer chains. Mono‐ and bi‐dentate ligands are observed to exhibit different degrees of bond strengths, which subsequently affect the mechanical properties of these Wolf‐type‐II metallopolymers. The counter ion also plays a crucial role, as it is observed that Py‐Fe mechanophores with non‐coordinating BPh 4 – counter ions (Py‐FeB) exhibit better thin film ductility with lower elastic modulus, as compared to the coordinating chloro ligands (Py‐FeC). Interestingly, besides mechanical robustness, the electrical charge carrier mobility can also be enhanced concurrently when incorporating Py‐FeB mechanophores in PSCs. This is a unique observation among stretchable PSCs, especially that most reports to date describe a decreased mobility when the stretchability is improved. Next, it is determined that improvements to both mobility and stretchability are correlated to the solid‐state molecular ordering and dynamics of coordination bonds under strain, as elucidated via techniques of grazing‐incidence X‐ray diffraction and X‐ray absorption spectroscopy techniques, respectively. This study provides a viable approach to enhance both the mechanical and the electronic performance of polymer‐based soft devices.