The development of layer-oriented two-dimensional conjugated metal-organic frameworks (2D c-MOFs) enables access to direct charge transport, dial-in lateral/vertical electronic devices, and the unveiling of transport mechanisms but remains a significant synthetic challenge. Here we report the novel synthesis of metal-phthalocyanine-based p-type semiconducting 2D c-MOF films (Cu2[PcM-O8], M = Cu or Fe) with an unprecedented edge-on layer orientation at the air/water interface. The edge-on structure formation is guided by the preorganization of metal-phthalocyanine ligands, whose basal plane is perpendicular to the water surface due to their π-πinteraction and hydrophobicity. Benefiting from the unique layer orientation, we are able to investigate the lateral and vertical conductivities by DC methods and thus demonstrate an anisotropic charge transport in the resulting Cu2[PcCu-O8] film. The directional conductivity studies combined with theoretical calculation identify that the intrinsic conductivity is dominated by charge transfer along the interlayer pathway. Moreover, a macroscopic (cm2 size) Hall-effect measurement reveals a Hall mobility of ∼4.4 cm2 V-1 s-1 for the obtained Cu2[PcCu-O8] film. The orientation control in semiconducting 2D c-MOFs will enable the development of various optoelectronic applications and the exploration of unique transport properties.
|Number of pages||9|
|Journal||Journal of the American Chemical Society|
|Publication status||Published - 2021 Sept 1|
Bibliographical noteFunding Information:
The authors thank Dr. Markus Löffler, Dr. Petr Formanek, Dr. Jichao Zhang, Prof. Xiaodong Zhuang, and Dr. Tao Zhang for SEM, TEM, XANES, XPS, and Raman measurements. The authors acknowledge cfaed and Dresden Center for Nanoanalysis (DCN) at TUD. This work is financially supported by EU Graphene Flagship (Core3, No. 881603), ERC starting grant (FC2DMOF, No. 852909), ERC Consolidator Grant (T2DCP), DFG projects (SFB-1415, No. 417590517, SPP 1928, WE 4893/6-1, COORNET), H2020-MSCA-ITN (ULTIMATE, No. 813036), as well as the German Science Council and Center of Advancing Electronics Dresden (cfaed). Z.W. gratefully acknowledges funding from the China Scholarship Council. R.T.W. acknowledges funding from the Center for Nanoscience (CeNS) and the Solar Technologies go Hybrid (SolTech) initiative as well as funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy-EXC-2111-390814868 (MCQST) and EXC 2089/1-390776260 (e-conversion). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by the MEXT, Japan, A3 Foresight by JSPS, and the CREST (JPMJCR15F3), JST. K.W. and T.T. acknowledge support from the EMEXT Element Strategy Initiative to Form Core Research Center, Grant Number JPMXP0112101001 and the CREST (JPMJCR15F3), JST. P.S.P. and T.H. thank ZIH Dresden for providing high-performance computing facilities. We acknowledge Elettra Sincrotrone Trieste for providing access to its synchrotron radiation facilities and we thank Luisa Barba for assistance in using beamline XRD1. The research leading to this result has been supported by the project CALIPSOplus under Grant Agreement 730872 from the EU Framework Programme for Research and Innovation HORIZON 2020.
All Science Journal Classification (ASJC) codes
- Colloid and Surface Chemistry