Iridium-based oxides: Recent advances in coloration mechanism, structural and morphological characterization

Backholm, Jonas; Avendaño, E.; Azens, A.; Azevedo, G. de M.; Coronel, Ernesto; Niklasson, Gunnar A.; Granqvist, Claes G.

doi:10.1016/j.solmat.2007.03.029

Cited by 24 publications

(17 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CV was performed between −0.3 and +1 V versus the Ag/ AgCl reference electrode at 20 mV/ s using an Ecochemie Autolab/GPES interface. One of our previous studies 33 indicated a 10% increase of oxygen content in the films during these initial cycles.…”

Section: Methodsmentioning

confidence: 67%

“…Additional structural characterization by atomic force microscopy, x-ray diffraction, transmission electron microscopy ͑TEM͒, Rutherford backscattering spectroscopy, and x-ray photoelectron spectroscopy of both types of films were presented in two recent papers. 32,33 The compositions of the as-deposited films were IrO 2.2 and IrTa 1.4 O 5.6 , respectively, with a surface roughness of about 9 nm and a grain size of 3 -4 nm for both types of films. Preliminary observations of cross section TEM images show that IrTaOx has a diffuse columnar structure, whereas the IrOx has a more porous structure, which is sensitive to electron beam irradiation.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Determination of solid phase chemical diffusion coefficient and density of states by electrochemical methods: Application to iridium oxide-based thin films

Backholm

Georén

Niklasson

2008

Journal of Applied Physics

View full text Add to dashboard Cite

Potentiostatic intermittent titration technique ͑PITT͒ and electrochemical impedance spectroscopy ͑EIS͒ were investigated as methods to determine solid phase chemical diffusion coefficient ͑D͒ and electronic density of states ͑DOS͒. These techniques were then applied to iridium oxide ͑IrOx͒ and iridium-tantalum oxide ͑IrTaOx͒ thin films prepared by sputter deposition. The experiments, performed in 1M propionic acid between −0.2 and 0.8 V vs Ag/ AgCl, showed effects of interfacial side reactions, whose contribution to the electrochemical response could be identified and corrected for in the case of PITT as well as EIS. It was found that D is strongly underestimated when using PITT with the common Cottrell formalism, which follows from non-negligible interfacial charge transfer and Ohmic resistances. EIS indicated an anomalous diffusion mechanism, and D was determined to be in the 10 −11 -10 −10 cm 2 / s range for IrOx and IrTaOx. Both PITT and EIS showed that the intercalated charge as a function of potential exhibits a shape that resembles the theoretical DOS of crystalline iridium oxide, especially for IrTaOx.

show abstract

Section: Methodsmentioning

confidence: 67%

Section: Methodsmentioning

confidence: 99%

Determination of solid phase chemical diffusion coefficient and density of states by electrochemical methods: Application to iridium oxide-based thin films

Backholm

Georén

Niklasson

2008

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…A multi target sputter system, based on a Balzers UTT400 unit, nm to 110 nm, using an Alpha Step profilometer. Additional structural characterization of the films was presented in recent papers [12,13]. The compositions of the as-deposited films were WO 3+/-0.1, IrO 2.2 and IrTa 1.4 O 5.6 , as obtained from Rutherford Backscattering Spectrometry and X-ray Photoelectron Spectroscopy.…”

Section: Methodsmentioning

confidence: 99%

Determination of electronic structure by impedance spectroscopy

Niklasson

Malmgren

Green

et al. 2010

Journal of Non-Crystalline Solids

View full text Add to dashboard Cite

We present a novel method, based on electrochemical intercalation and impedance spectroscopy, to determine the electronic density of states of disordered transition metal oxides. Specifically, we have determined the "electrochemical density of states" of tungsten and iridium oxide thin films over energy ranges as wide as 1 to 2 eV. Our experimental results show a number of qualitative features exhibited by state-of-the-art band structure computations. Differences in details are probably due to the disordered, porous and sometimes amorphous nature of our films. The results suggest that the impedance spectroscopy method can be used to obtain the density of states only if the conduction band states are localized. The electrochemical density of states is often smaller than the computed one due to kinetic effects, i.e. very slow relaxations of the charge carriers. Nevertheless, our sensitive method opens new vistas for studying the electronic structure of disordered materials.

show abstract

“…For most EC devices-including -smart‖ windows-it is desirable to have a large CE. well as transmission electron microscopy in earlier work [15,29].…”

Section: Electrochemical and Optical Measurementsmentioning

confidence: 82%

“…Ir oxide has been studied in this context at least since 1978 [10,11], and sputter deposited EC films were reported in 1979 [12]; the early literature has been reviewed in detail [1]. The research field maintains its vitality [13][14][15][16][17][18][19][20]. Concerning durability, we notice that Ir oxide films have undergone EC cycling for up to 7 × 10 6 ion insertion/extraction cycles without significant degradation [21].…”

Section: There Are Two Types Of Ec Thin Films: One Is Called -Cathodimentioning

confidence: 95%

Electrochromic nickel oxide films and their compatibility with potassium hydroxide and lithium perchlorate in propylene carbonate: Optical, electrochemical and stress-related properties

2014

View full text Add to dashboard Cite

Electrochromic nickel oxide films and their compatibility with potassium hydroxide and lithium perchlorate in propylene carbonate: Optical, electrochemical and stress-related properties. AbstractPorous thin films of Ir oxide were prepared by reactive dc magnetron sputtering onto unheated substrates. The crystallite size was ~5 nm, and a small amount of unoxidized Ir was present. The electrochromic performance was studied by optical transmittance measurements and cyclic voltammetry applied to films in aqueous and non-aqueous electrolytes, specifically being 1M propionic acid, 1M potassium hydroxide (KOH), and 1M lithium perchlorate in propylene carbonate (Li-PC). Cyclic voltammetry measurements indicated that the films had a fractal surface structure. Good electrochromism, with mid-luminous transmittance modulation between ~55 and ~90 % in ~100-nm-thick films, was documented in all of the electrolytes.

show abstract

Iridium-based oxides: Recent advances in coloration mechanism, structural and morphological characterization

Cited by 24 publications

References 9 publications

Determination of solid phase chemical diffusion coefficient and density of states by electrochemical methods: Application to iridium oxide-based thin films

Determination of solid phase chemical diffusion coefficient and density of states by electrochemical methods: Application to iridium oxide-based thin films

Determination of electronic structure by impedance spectroscopy

Electrochromic nickel oxide films and their compatibility with potassium hydroxide and lithium perchlorate in propylene carbonate: Optical, electrochemical and stress-related properties

Contact Info

Product

Resources

About