Amorphous transition metal oxides are recognized as leading candidates for electrochromic window coatings that can dynamically modulate solar irradiation and improve building energy efficiency. However, their thin films are normally prepared by energy-intensive sputtering techniques or high-temperature solution methods, which increase manufacturing cost and complexity. Here, we report on a room-temperature solution process to fabricate electrochromic films of niobium oxide glass (NbOx) and ‘nanocrystal-in-glass’ composites (that is, tin-doped indium oxide (ITO) nanocrystals embedded in NbOx glass) via acid-catalysed condensation of polyniobate clusters. A combination of X-ray scattering and spectroscopic characterization with complementary simulations reveals that this strategy leads to a unique one-dimensional chain-like NbOx structure, which significantly enhances the electrochromic performance, compared to a typical three-dimensional NbOx network obtained from conventional high-temperature thermal processing. In addition, we show how self-assembled ITO-in-NbOx composite films can be successfully integrated into high-performance flexible electrochromic devices.
Subscribe to Journal
Get full journal access for 1 year
only $17.42 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Kim, Y.-H. et al. Flexible metal-oxide devices made by room-temperature photochemical activation of sol–gel films. Nature 489, 128–132 (2014).
Banger, K. K. et al. Low-temperature, high-performance solution-processed metal oxide thin-film transistors formed by a ‘sol–gel on chip’ process. Nat. Mater. 10, 45–50 (2011).
Kim, M-G., Kanatzidis, M. G., Facchetti, A. & Marks, T. J. Low-temperature fabrication of high-performance metal oxide thin-film electronics via combustion processing. Nat. Mater. 10, 382–388 (2011).
Granqvist, C. G. Electrochromics for smart windows: Oxide-based thin films and devices. Thin Solid Films 564, 1–38 (2014).
Legrain, F., Malyi, O. & Manzhos, S. Insertion energetics of lithium, sodium, and magnesium in crystalline and amorphous titanium dioxide: a comparative first-principles study. J. Power Sources 278, 197–202 (2015).
Chae, O. B. et al. Reversible lithium storage at highly populated vacant sites in an amorphous vanadium pentoxide electrode. Chem. Mater. 26, 5874–5881 (2014).
Colton, R. J., Guzman, A. M. & Rabalais, J. W. Photochromism and electrochromism in amorphous transition metal oxide films. Acc. Chem. Res. 11, 170–176 (1978).
Jang, J. et al. Electrode performances of amorphous molybdenum oxides of different molybdenum valence for lithium-ion batteries. Isr. J. Chem. 55, 604–610 (2015).
Ku, J. H., Ryu, J. H., Kim, S. H., Han, O. H. & Oh, S. M. Reversible lithium storage with high mobility at structural defects in amorphous molybdenum dioxide electrode. Adv. Funct. Mater. 22, 3658–3664 (2012).
Uchaker, E. et al. Better than crystalline: amorphous vanadium oxide for sodium-ion batteries. J. Mater. Chem. A 2, 18208–18214 (2014).
Lee, J. et al. Unlocking the potential of cation-disordered oxides for rechargeable lithium batteries. Science 343, 519–522 (2014).
Shelby, J. E. Introduction to Glass Science and Technology (Royal Society of Chemistry, 2005); http://dx.doi.org/10.1039/9781847551160
Sakamoto, A. & Yamamoto, S. Glass-ceramics: engineering principles and applications. Int. J. Appl. Glass Sci. 1, 237–247 (2010).
Llordes, A., Garcia, G., Gazquez, J. & Milliron, D. J. Tunable near-infrared and visible-light transmittance in nanocrystal-in-glass composites. Nature 500, 323–326 (2013).
Granqvist, C. G. Electrochromic tungsten oxide films: review of progress 1993–998. Sol. Energy Mater Sol. Cells 60, 201–262 (2000).
Runnerstrom, E. L., Llordes, A., Lounis, S. D. & Milliron, D. J. Nanostructured electrochromic smart windows: traditional materials and NIR-selective plasmonic nanocrystals. Chem. Commun. 50, 10555–10572 (2014).
Kim, J. et al. Nanocomposite architecture for rapid, spectrally-selective electrochromic modulation of solar transmittance. Nano Lett. 15, 5574–5579 (2015).
Granqvist, C. G. et al. Electrochromic foil-based devices: Optical transmittance and modulation range, effect of ultraviolet irradiation, and quality assessment by 1/f current noise. Thin Solid Films 516, 5921–5926 (2008).
Arakaki, J., Reyes, R., Horn, M. & Estrada, W. Electrochromism in NiOx and WOx obtained by spray pyrolysis. Sol. Energy Mater Sol. Cells 37, 33–41 (1995).
Orel, B., Maček, M., Grdadolnik, J. & Meden, A. In situ UV-Vis and ex situ IR spectroelectrochemical investigations of amorphous and crystalline electrochromic Nb2O5 films in charged/discharged states. J. Solid State Electrochem. 2, 221–236 (1998).
Costa, C., Pinheiro, C., Henriques, I. & Laia, C. A. T. Inkjet printing of sol-gel synthesized hydrated tungsten oxide nanoparticles for flexible electrochromic devices. ACS Appl. Mater. Interfaces 4, 1330–1340 (2012).
Mihelčič, M. et al. Comparison of electrochromic properties of Ni1−xO in lithium and lithium-free aprotic electrolytes: From Ni1−xO pigment coatings to flexible electrochromic devices. Sol. Energy Mater Sol. Cells 120, 116–130 (2014).
Layani, M. et al. Nanostructured electrochromic films by inkjet printing on large area and flexible transparent silver electrodes. Nanoscale 6, 4572–4576 (2014).
Ohlin, C. A., Villa, E. M. & Casey, W. H. One-pot synthesis of the decaniobate salt [N(CH3)4]6[Nb10O28] ⋅ 6H2O from hydrous niobium oxide. Inorg. Chim. Acta 362, 1391–1392 (2009).
Villa, E. M. et al. Reaction dynamics of the decaniobate ion [HxNb10O28](6−x)− in water. Angew. Chem. Int. Ed. Engl. 47, 4844–4846 (2008).
Hou, Y., Zakharov, L. N. & Nyman, M. Observing assembly of complex inorganic materials from polyoxometalate building blocks. J. Am. Chem. Soc. 135, 16651–16657 (2013).
Wang, Y. & Weinstock, I. A. Cation mediated self-assembly of inorganic cluster anion building blocks. Dalton Trans. 39, 6143–6152 (2010).
Wang, Y. et al. Self-assembly and structure of directly imaged inorganic-anion monolayers on a gold nanoparticle. J. Am. Chem. Soc. 131, 17412–17422 (2009).
Musumeci, C., Luzio, A. & Pradeep, C. P. Programmable surface architectures derived from hybrid polyoxometalate-based clusters. J. Phys. Chem. C 115, 4446–4455 (2011).
Livage, J. Vanadium pentoxide gels. Chem. Mater. 3, 578–593 (1991).
Boily, J.-F. & Felmy, A. R. On the protonation of oxo- and hydroxo-groups of the goethite (α-FeOOH) surface: A FTIR spectroscopic investigation of surface O–H stretching vibrations. Geochim. Cosmochim. Acta 72, 3338–3357 (2008).
Tsyganenko, A. A. & Filimonov, V. N. Infrared spectra of surface hydroxyl groups and crystalline structure of oxides. J. Mol. Struct. 19, 579–589 (1973).
Judeinstein, P., Morineau, R. & Livage, J. Electrochemical degradation of WO3 ⋅ nH2O thin films. Solid State Ion. 51, 239–247 (1992).
Cliffe, M. J., Dove, M. T., Drabold, D. A. & Goodwin, A. L. Structure determination of disordered materials from diffraction data. Phys. Rev. Lett. 104, 125501 (2010).
McConnell, A. A., Aderson, J. S. & Rao, C. N. R. Raman spectra of niobium oxides. Spectrochim. Acta Mol. Biomol. Spectrosc. 32, 1067–1076 (1976).
Fonari, A. & Stauffer, S. Raman Off-Resonant Activity Calculator Using VASP as a Back-end vasp_raman.py (2013); https://github.com/raman-sc/VASP
Granlund, L., Billinge, S. J. L. & Duxbury, P. M. Algorithm for systematic peak extraction from atomic pair distribution functions. Acta Crystallogr. Sect. A 71, 392–409 (2015).
McGreevy, R. L. Reverse Monte Carlo modelling. J. Phys.: Condens. Matter. 13, R877–R913 (2001).
Rustad, J. R. & Casey, W. H. Metastable structures and isotope exchange reactions in polyoxometalate ions provide a molecular view of oxide dissolution. Nat. Mater. 11, 223–226 (2012).
Chemseddine, A. & Bloeck, U. How isopolyanions self-assemble and condense into a 2D tungsten oxide crystal: HRTEM imaging of atomic arrangement in an intermediate new hexagonal phase. J. Solid State Chem. 181, 2731–2736 (2008).
Liang, L. et al. High-performance flexible electrochromic device based on facile semiconductor-to-metal transition realized by WO3 ⋅ 2H2O ultrathin nanosheets. Sci. Rep. 3, 1936 (2013).
Miyauchi, M., Kondo, A., Atarashi, D. & Sakai, E. Tungstate nanosheet ink as a photonless and electroless chromic device. J. Mater. Chem. C 2, 3732–3737 (2014).
Wu, C. et al. Two-dimensional vanadyl phosphate ultrathin nanosheets for high energy density and flexible pseudocapacitors. Nat. Commun. 4, 2431 (2013).
Triana, C. A., Granqvist, C. G. & Niklasson, G. A. Electrochromism and small-polaron hopping in oxygen deficient and lithium intercalated amorphous tungsten oxide films. J. Appl. Phys. 118, 024901 (2015).
Triana, C. A., Granqvist, C. G. & Niklasson, G. A. Optical absorption and small-polaron hopping in oxygen deficient and lithium-ion-intercalated amorphous titanium oxide films. J. Appl. Phys. 119, 015701 (2016).
Lubimtsev, A. A., Kent, P. R. C., Sumpter, B. G. & Ganesh, P. Understanding the origin of high-rate intercalation pseudocapacitance in Nb2O5 crystals. J. Mater. Chem. A 1, 14951–14956 (2013).
Wang, Y., Runnerstom, E. L. & Milliron, D. J. Switchable materials for smart windows. Annu. Rev. Chem. Biomol. Eng. 7, 283–304 (2016).
Williams, T. E. et al. NIR-Selective electrochromic heteromaterial frameworks: a platform to understand mesoscale transport phenomena in solid-state electrochemical devices. J. Mater. Chem. C 2, 3328–3335 (2014).
Llordes, A. et al. Polyoxometalates and colloidal nanocrystals as building blocks for metal oxide nanocomposite films. J. Mater. Chem. 21, 11631–11638 (2011).
Hammersley, A. P., Svensson, S. O., Hanfland, M., Fitch, A. N. & Hausermann, D. Two-dimensional detector software: from real detector to idealised image or two-theta scan. High Press. Res. 14, 235–248 (1996).
Juhas, P., Davis, T., Farrow, C. L. & Billinge, S. J. L. PDFgetX3: a rapid and highly automatable program for processing powder diffraction data into total scattering pair distribution functions. J. Appl. Crystallogr. 46, 560–566 (2013).
Farrow, C. L. et al. PDFfit2 and PDFgui: computer programs for studying nanostructure in crystals. J. Phys.: Condens. Matter. 19, 335219 (2007).
Liu, Y., He, S., Uehara, M. & Maeda, H. Wet chemical preparation of well-dispersed colloidal cerium oxide nanocrystals. Chem. Lett. 36, 764–765 (2007).
This work was carried out at the University of Texas at Austin and the Molecular Foundry, Lawrence Berkeley National Laboratory, a user facility supported by the Office of Science, Office of Basic Energy Sciences, of the US Department of Energy under contract no. DE-AC02-05CH11231. This research was supported by a US Department of Energy ARPA-E grant. D.J.M. and G.H. acknowledge support of the Welch Foundation (F-1848 and F-1841, respectively). PDF measurements were performed at beamline ID15B of the European Synchrotron Radiation Facility (ESRF), Grenoble, France. GIWAXS data was acquired at beamline 11–3 of the Stanford Synchrotron Radiation Lightsource (SSRL). We thank D. Van Campen and C. Miller for assistance at SSRL. We also thank B. Koo for providing some of the ITO and CeO2 nanocrystals, as well as G. Garcia and J. Rivest for helpful discussions.
D.J.M. has a financial interest in Heliotrope Technologies, a company pursuing commercial development of electrochromic devices.
About this article
Cite this article
Llordés, A., Wang, Y., Fernandez-Martinez, A. et al. Linear topology in amorphous metal oxide electrochromic networks obtained via low-temperature solution processing. Nature Mater 15, 1267–1273 (2016). https://doi.org/10.1038/nmat4734
The Advances of Metal Sulfides and In Situ Characterization Methods beyond Li Ion Batteries: Sodium, Potassium, and Aluminum Ion Batteries
Small Methods (2020)
Chemistry of Materials (2020)
ACS Nano (2020)
Cephalopod-inspired versatile design based on plasmonic VO2 nanoparticle for energy-efficient mechano-thermochromic windows
Nano Energy (2020)
Fusing electrochromic technology with other advanced technologies: A new roadmap for future development
Materials Science and Engineering: R: Reports (2020)