Two-dimensional conjugated metal-organic frameworks (2D c-MOFs) are emerging as a unique class of electronic materials but have been found to be intrinsically metallic or possess a low bandgap. 2D c-MOFs with open band gaps in the Vis-NIR and high carrier mobilities are still rare, limiting the application of 2D c-MOFs in logic devices. The researchers of the group of Prof. Xinliang Feng in collaboration with researchers from Stockholm University and IMDEA Nanociencia (Madrid) report a new ligand design that increases the out-of-plane mobility while keeping an open band gap. The D2h-symmetric π-extended ligand (OHPTP), and the derived rhombic 2D c-MOF single crystals (Cu2(OHPTP)) are unambiguously characterized on the single crystal level by continuous rotation electron diffraction (cRED) revealing the orthorhombic crystal structure at the atomic level with an unique AB layer stacking. Electrical characterization and terahertz spectroscopic studies show that Cu2(OHPTP) is a p-type semiconductor with an indirect band gap of ~0.50 eV and a high electrical conductivity of 0.10 S cm-1 as well as a high charge carrier mobility of ~10.0 cm2V-1s-1. The open bandgap and high out-of-plane band dispersion are further confirmed by DFT calculations. The findings have been published in the journal Angewandte Chemie International Edition.
This work was financially supported by the ERC starting grant (FC2DMOF, No. 852909), ERC Consolidator Grant (T2DCP, No. 819698), DFG project (CRC-1415, No. 417590517), EMPIR-20FUN03-COMET, as well as the German Science Council and Center for Advancing Electronics Dresden (cfaed). Further support was provided by the Taishan Scholars Program of Shandong Province (tsqn201909047) and the National Natural Science Foundation of China (22272092); the MCIN/AEI grant PID2019-107808RA-I00 and Comunidad de Madrid grants 2021-5A/AMB-20942 & P2018/NMT-451; the MSCA HORIZON 2020 funding via 101030872 – PhoMOFs grant and the Swedish Research Council Formas (2020-00831), and the Swedish Research Council (VR, 2022-02939).
Reference: Lukas Sporrer, Guojun Zhou, Mingchao Wang, Vasileios Balos, Sergio Revuelta, Kamil Jastrzembski, Markus Löffler, Petko Petkov, Thomas Heine, Angieszka Kuc, Enrique Cánovas, Zhehao Huang, Xinliang Feng, Renhao Dong, Near IR bandgap semiconducting 2D conjugated metal-organic framework with rhombic lattice and high mobility, https://doi.org/10.1002/anie.202300186.