Metal–Ligand Based Mechanophores Enhance Both Mechanical Robustness and Electronic Performance of Polymer Semiconductors
Abstract
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 BPh4– 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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 12, 2021
- Source ID
- 10.1002/adfm.202009201
Entities
People
- Baohua Ji
- David M. Koshy
- Dechang Li
- Fan Wang
- Franziska Lissel
- Gi Xue
- Ging‐ji Nathan Wang
- Hongping Yan
- Hung-Chin Wu
- Jie Xu
- Naoji Matsuhisa
- Shaochuan Luo
- Shayla Nikzad
- Wen‐chang Chen
- Yuan Cheng
- Zhenan Bao
Organizations
- Air Force Office of Scientific Research
- Japan Society for the Promotion of Science
- Nanjing University
- National Science Foundation
- National Science and Technology Council
- SLAC National Accelerator Laboratory
- Stanford University
- Swiss National Science Foundation
- United States Department of Energy
- Zhejiang University