Electrically conductive coordination polymers and metal-organic frameworks are attractive emerging electroactive materials for (opto-)electronics. However, developing semiconducting coordination polymers with high charge carrier mobility for devices remains a major challenge, urgently requiring the rational design of ligands and topological networks with desired electronic structures. Herein, we demonstrate a strategy for synthesizing high-mobility semiconducting conjugated coordination polymers (c-CPs) utilizing novel conjugated ligands with D2h symmetry, namely, “4 + 2” phenyl ligands. Compared with the conventional phenyl ligands with C6h symmetry, the reduced symmetry of the “4 + 2” ligands leads to anisotropic coordination in the formation of c-CPs. Consequently, we successfully achieve a single-crystalline three-dimensional (3D) c-CP Cu4DHTTB (DHTTB = 2,5-dihydroxy-1,3,4,6-tetrathiolbenzene), containing orthogonal ribbon-like π-d conjugated chains rather than 2D conjugated layers. DFT calculation suggests that the resulting Cu4DHTTB exhibits a small band gap (∼0.2 eV), strongly dispersive energy bands near the Fermi level with a low electron-hole reduced effective mass (∼0.2m0*). Furthermore, the four-probe method reveals a semiconducting behavior with a decent conductivity of 0.2 S/cm. Thermopower measurement suggests that it is a p-type semiconductor. Ultrafast terahertz photoconductivity measurements confirm Cu4DHTTB’s semiconducting nature and demonstrate the Drude-type transport with high charge carrier mobilities up to 88 ± 15 cm2 V-1 s-1, outperforming the conductive 3D coordination polymers reported till date. This molecular design strategy for constructing high-mobility semiconducting c-CPs lays the foundation for achieving high-performance c-CP-based (opto-)electronics.
|Number of pages||9|
|Journal||Journal of the American Chemical Society|
|Publication status||Published - 2023 Feb 1|
Bibliographical noteFunding Information:
This work is financially supported by the EU Graphene Flagship (Core3, no. 881603), ERC starting grant (FC2DMOF, no. 852909), ERC Consolidator grant (T2DCP), DFG projects (SFB-1415, no. 417590517, SPP 1928, COORNET), as well as the German Science Council and Center for Advancing Electronics Dresden (cfaed). R.D. thanks the Taishan Scholars Program of Shandong Province (tsqn201909047) and the National Natural Science Foundation of China (22272092). I.W. acknowledges the cluster of excellence UniSysCat (EXC 2008/1-390540038). P.S.P. acknowledges the Center for information services and high-performance computing (ZIH) at TU-Dresden. X.H. thanks Dr. J. Y. Huang for her valuable suggestions. X.H. also thanks Z.L. and Y.L. for their assistance with thermoelectric data collection.
© 2023 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry