Band transport; Electrical transport measurements; Electrochemical energy storage; Layered material; Long range transport; Optoelectronic applications; Tera Hertz; Theoretical study; Thermally activated hopping; Ultra-fast; Physics and Astronomy (all); General Physics and Astronomy
Abstract :
[en] MXenes are emerging layered materials that are promising for electrochemical energy storage and (opto-)electronic applications. A fundamental understanding of charge transport in MXenes is essential for such applications, but has remained under debate. While theoretical studies pointed to efficient band transport, device measurements have revealed thermally activated, hopping-type transport. Here we present a unifying picture of charge transport in two model MXenes by combining ultrafast terahertz and static electrical transport measurements to distinguish the short- and long-range transport characteristics. We find that band-like transport dominates short-range, intra-flake charge conduction in MXenes, whereas long-range, inter-flake transport occurs through thermally activated hopping, and limits charge percolation across the MXene flakes. Our analysis of the intra-flake charge carrier scattering rate shows that it is dominated by scattering from longitudinal optical phonons with a small coupling constant (α ≈ 1), for both semiconducting and metallic MXenes. This indicates the formation of large polarons in MXenes. Our work therefore provides insight into the polaronic nature of free charges in MXenes, and unveils intra- and inter-flake transport mechanisms in the MXene materials, which are relevant for both fundamental studies and applications.
Disciplines :
Chemistry
Author, co-author :
Zheng, Wenhao; Max Planck Institute for Polymer Research, Mainz, Germany
Sun, Boya; Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany ; State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
Li, Dongqi ; Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
Gali, Sai Manoj; Laboratory for Chemistry of Novel Materials, Université de Mons, Mons, Belgium
Zhang, Heng ; Max Planck Institute for Polymer Research, Mainz, Germany
Fu, Shuai; Max Planck Institute for Polymer Research, Mainz, Germany
Di Virgilio, Lucia; Max Planck Institute for Polymer Research, Mainz, Germany
Li, Zichao; Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
Yang, Sheng ; Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
Zhou, Shengqiang ; Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
Yu, Minghao; Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
Feng, Xinliang ; Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany ; Max Planck Institute of Microstructure Physics, Halle, Germany
Wang, Hai I. ; Max Planck Institute for Polymer Research, Mainz, Germany
Bonn, Mischa ; Max Planck Institute for Polymer Research, Mainz, Germany
Financial support by the Max Planck Society is acknowledged. This work was financially supported by the European Union’s Horizon 2020 research and innovation programme (GrapheneCore3 881603) and Deutsche Forschungsgemeinschaft (MX-OSMOPED project and CRC 1415 (grant no. 417590517)). The work in Mons is financially supported by FLAG-ERA JTC 2017 project MX-OSMOPED, the Belgian National Fund for Scientific Research (FRS-FNRS), the Consortium des Équipements de Calcul Intensif (CÉCI) under grant no. 2.5020.11 and by the Walloon Region (ZENOBE Tier-1 supercomputer, grant no. 1117545). D.B. is FNRS Research Director. We thank K. Krewer, M. Grechko, M. Ballabio, X. Jia and A. Tries for fruitful discussions. We acknowledge P. Kumar, H. Kim and R. Ulbricht for constructive comments on the manuscript. We are grateful to H. Burg and R. Berger for conducting AFM image measurements. S.F. acknowledges fellowship support from the Chinese Scholarship Council (CSC). L.D.V. acknowledges support from the EU Horizon 2020 Framework Programme (grant no. 811284).
VahidMohammadi, A., Rosen, J. & Gogotsi, Y. The world of two-dimensional carbides and nitrides (MXenes). Science 372, eabf1581 (2021). DOI: 10.1126/science.abf1581
Jiang, X. et al. Two-dimensional MXenes: from morphological to optical, electric and magnetic properties and applications. Phys. Rep. 848, 1–58 (2020). DOI: 10.1016/j.physrep.2019.12.006
Hantanasirisakul, K. & Gogotsi, Y. Electronic and optical properties of 2D transition metal carbides and nitrides (MXenes). Adv. Mater. 30, 1804779 (2018). DOI: 10.1002/adma.201804779
Kamysbayev, V. et al. Covalent surface modifications and superconductivity of two-dimensional metal carbide MXenes. Science 369, 979–983 (2020). DOI: 10.1126/science.aba8311
Han, M. et al. Tailoring electronic and optical properties of MXenes through forming solid solutions. J. Am. Chem. Soc. 142, 19110–19118 (2020). DOI: 10.1021/jacs.0c07395
Lipatov, A. et al. Electrical and elastic properties of individual single-layer Nb4C3Tx MXene flakes. Adv. Electron. Mater. 6, 1901382 (2020). DOI: 10.1002/aelm.201901382
Halim, J. et al. Variable range hopping and thermally activated transport in molybdenum-based MXenes. Phys. Rev. B 98, 104202 (2018). DOI: 10.1103/PhysRevB.98.104202
Hart, J. L. et al. Control of MXenes’ electronic properties through termination and intercalation. Nat. Commun. 10, 522 (2019). DOI: 10.1038/s41467-018-08169-8
Jing, Z. et al. Electron–phonon scattering limited intrinsic electrical conductivity of MXenes X2C (X = Ti or Mo). J. Phys. D 54, 015301 (2021). DOI: 10.1088/1361-6463/abb84a
Xu, M., Yang, J. & Liu, L. Temperaÿture-dependent optical and electrical properties of bulk Ti2AlC and two-dimensional MXenes from first-principles. Physica B 560, 146–154 (2019). DOI: 10.1016/j.physb.2019.02.025
Zhang, X., Zhao, X., Wu, D., Jing, Y. & Zhou, Z. High and anisotropic carrier mobility in experimentally possible Ti2CO2 (MXene) monolayers and nanoribbons. Nanoscale 7, 16020–16025 (2015). DOI: 10.1039/C5NR04717J
Alexandrov, A. S. &; Devreese, J. T. Advances in Polaron Physics (Springer, 2010).
Franchini, C., Reticcioli, M., Setvin, M. & Diebold, U. Polarons in materials. Nat. Rev. Mater. 6, 560–586 (2021). DOI: 10.1038/s41578-021-00289-w
Mei, Y. et al. Crossover from band-like to thermally activated charge transport in organic transistors due to strain-induced traps. Proc. Natl Acad. Sci. USA 114, 6739–6748 (2017). DOI: 10.1073/pnas.1705164114
Djire, A., Zhang, H., Liu, J., Miller, E. M. & Neale, N. R. Electrocatalytic and optoelectronic characteristics of the two-dimensional titanium nitride Ti4N3Tx MXene. ACS Appl. Mater. Interfaces 11, 11812–11823 (2019). DOI: 10.1021/acsami.9b01150
Ulbricht, R., Hendry, E., Shan, J., Heinz, T. F. & Bonn, M. Carrier dynamics in semiconductors studied with time-resolved terahertz spectroscopy. Rev. Mod. Phys. 83, 543–586 (2011). DOI: 10.1103/RevModPhys.83.543
Tielrooij, K. J. et al. Photoexcitation cascade and multiple hot-carrier generation in graphene. Nat. Phys. 9, 248–252 (2013). DOI: 10.1038/nphys2564
Fu, S. et al. Long-lived charge separation following pump-wavelength-dependent ultrafast charge transfer in graphene/WS2 heterostructures. Sci. Adv. 7, eabd9061 (2021). DOI: 10.1126/sciadv.abd9061
Zheng, W., Bonn, M. & Wang, H. I. Photoconductivity multiplication in semiconducting few-layers MoTe2. Nano Lett. 20, 5807–5813 (2020). DOI: 10.1021/acs.nanolett.0c01693
Shan, J., Wang, F., Knoesel, E., Bonn, M. & Heinz, T. F. Measurement of the frequency-dependent conductivity in sapphire. Phys. Rev. Lett. 90, 247401 (2003). DOI: 10.1103/PhysRevLett.90.247401
Němec, H., Kužel, P. & Sundström, V. Charge transport in nanostructured materials for solar energy conversion studied by time-resolved terahertz spectroscopy. J. Photochem. Photobiol. A 215, 123–139 (2010). DOI: 10.1016/j.jphotochem.2010.08.006
Ballabio, M., Fuertes Marron, D., Barreau, N., Bonn, M. & Canovas, E. Composition-dependent passivation efficiency at the CdS/CuIn1-xGaxSe2 interface. Adv. Mater. 32, 1907763 (2020). DOI: 10.1002/adma.201907763
Li, G. et al. Dynamÿical control over terahertz electromagnetic interference shielding with 2D Ti3C2Ty MXene by ultrafast optical pulses. Nano Lett. 20, 636–643 (2020). DOI: 10.1021/acs.nanolett.9b04404
Jacoboni, C. Theory of Electron Transport in Semiconductors (Springer, 2010).
Ippolito, S. et al. Covalently interconnected transition metal dichalcogenide networks via defect engineering for high-performance electronic devices. Nat. Nanotechnol. 16, 592–598 (2021). DOI: 10.1038/s41565-021-00857-9
Cocker, T. L. et al. Microscopic origin of the Drude-Smith model. Phys. Rev. B 96, 205439 (2017). DOI: 10.1103/PhysRevB.96.205439
Li, G., Natu, V., Shi, T., Barsoum, M. W. & Titova, L. V. Two-dimensional MXenes Mo2Ti2C3Tz and Mo2TiC2Tz: microscopic conductivity and dynamics of photoexcited carriers. ACS Appl. Energy Mater. 3, 1530–1539 (2020). DOI: 10.1021/acsaem.9b01966
Bardeen, J. & Shockley, W. Deformation potentials and mobilities in non-polar crystals. Phys. Rev. 80, 72–80 (1950). DOI: 10.1103/PhysRev.80.72
Low, F. E. & Pines, D. Mobility of slow electrons in polar crystals. Phys. Rev. 98, 414–418 (1955). DOI: 10.1103/PhysRev.98.414
Bafekry, A., Akgenc, B., Ghergherehchi, M. & Peeters, F. M. Strain and electric field tuning of semi-metallic character WCrCO2 MXenes with dual narrow band gap. J. Phys. Condens. Matter 32, 355504 (2020). DOI: 10.1088/1361-648X/ab8e88
Luo, Y., Cheng, C., Chen, H. J., Liu, K. & Zhou, X. L. Systematic investigations of the electron, phonon and elastic properties of monolayer M2C (M = V, Nb, Ta) by first-principles calculations. J. Phys. Condens. Matter 31, 405703 (2019). DOI: 10.1088/1361-648X/ab2847
Hu, T. et al. Vibrational properties of Ti3C2 and Ti3C2T2 (T = O, F, OH) monosheets by first-principles calculations: a comparative study. Phys. Chem. Chem. Phys. 17, 9997–10003 (2015). DOI: 10.1039/C4CP05666C
Feynman, R. P., Hellwarth, R. W., Iddings, C. K. & Platzman, P. M. Mobility of slow electrons in a polar crystal. Phys. Rev. 127, 1004–1017 (1962). DOI: 10.1103/PhysRev.127.1004
Hendry, E., Wang, F., Shan, J., Heinz, T. F. & Bonn, M. Electron transport in TiO2 probed by THz time-domain spectroscopy. Phys. Rev. B 69, 081101 (2004). DOI: 10.1103/PhysRevB.69.081101
Frost, J. M. Calculating polaron mobility in halide perovskites. Phys. Rev. B 96, 195202 (2017). DOI: 10.1103/PhysRevB.96.195202
Sio, W. H., Verdi, C., Poncé, S. & Giustino, F. Ab initio theory of polarons: formalism and applications. Phys. Rev. B 99, 235139 (2019). DOI: 10.1103/PhysRevB.99.235139
Sio, W. H., Verdi, C., Ponce, S. & Giustino, F. Polarons from first principles, without supercells. Phys. Rev. Lett. 122, 246403 (2019). DOI: 10.1103/PhysRevLett.122.246403
Berdiyorov, G. R. Optical properties of functionalized Ti3C2T2 (T = F, O, OH) MXene: first-principles calculations. AIP Adv. 6, 055105 (2016). DOI: 10.1063/1.4948799
Zhu, H. et al. Screening in crystalline liquids protects energetic carriers in hybrid perovskites. Science 353, 1409–1413 (2016). DOI: 10.1126/science.aaf9570
Zhang, H. et al. Highly mobile large polarons in black phase CsPbI3. ACS Energy Lett. 6, 568–573 (2021). DOI: 10.1021/acsenergylett.0c02482
Giustino, F. Electron-phonon interactions from first principles. Rev. Mod. Phys. 89, 015003 (2017). DOI: 10.1103/RevModPhys.89.015003
Wang, Z. et al. Tailoring the nature and strength of electron–phonon interactions in the SrTiO3 (001) 2D electron liquid. Nat. Mater. 15, 835–839 (2016). DOI: 10.1038/nmat4623
Ito, T. et al. Electronic structure of Cr2AlC as observed by angle-resolved photoemission spectroscopy. Phys. Rev. B 96, 195168 (2017). DOI: 10.1103/PhysRevB.96.195168
Zhao, S. et al. Flexible Nb4C3Tx film with large interlayer spacing for high-performance supercapacitors. Adv. Funct. Mater. 30, 2000815 (2020). DOI: 10.1002/adfm.202000815
Bai, X. et al. Two-dimensional semiconducting Lu2CT2 (T = F, OH) MXene with low work function and high carrier mobility. Nanoscale 12, 3795–3802 (2020). DOI: 10.1039/C9NR10806H
Yang, Y. et al. Distinguishing electronic contributions of surface and sub-surface transition metal atoms in Ti-based MXenes. 2D Mater. 7, 025015 (2020). DOI: 10.1088/2053-1583/ab68e7
Zha, X. H. et al. Promising electron mobility and high thermal conductivity in Sc2CT2 (T = F, OH) MXenes. Nanoscale 8, 6110–6117 (2016). DOI: 10.1039/C5NR08639F
Luo, K. et al. First-principles study on the electrical and thermal properties of the semiconducting Sc3(CN)F2 MXene. RSC Adv. 8, 22452–22459 (2018). DOI: 10.1039/C8RA03424A
Lipatov, A. et al. Elastic properties of 2D Ti3C2Tx MXene monolayers and bilayers. Sci. Adv. 4, eaat0491 (2018). DOI: 10.1126/sciadv.aat0491
Hu, T. et al. Anisotropic electronic conduction in stacked two-dimensional titanium carbide. Sci. Rep. 5, 16329 (2015). DOI: 10.1038/srep16329
Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169 (1996). DOI: 10.1103/PhysRevB.54.11169
Kresse, G., Marsman, M. &; Furthmüller, J. VASP (2012); https://www.vasp.at/
Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996). DOI: 10.1103/PhysRevLett.77.3865
Grimme, S. Semiempirical GGA‐type density functional constructed with a long‐range dispersion correction. J. Comput. Chem. 27, 1787–1799 (2006). DOI: 10.1002/jcc.20495
Madsen, G. K. H. & Singh, D. J. BoltzTraP. A code for calculating band-structure dependent quantities. Comput. Phys. Commun. 175, 67–71 (2006). DOI: 10.1016/j.cpc.2006.03.007
Xi, J., Long, M., Tang, L., Wang, D. & Shuai, Z. First-principles prediction of charge mobility in carbon and organic nanomaterials. Nanoscale 4, 4348–4369 (2012). DOI: 10.1039/c2nr30585b
Slassi, A. et al. Interlayer bonding in two-dimensional materials: the special case of SnP3 and GeP3. J. Phys. Chem. Lett. 11, 4503–4510 (2020). DOI: 10.1021/acs.jpclett.0c00780
