Electrochromic iridium oxide films: Compatibility with propionic acid, potassium hydroxide, and lithium perchlorate in propylene carbonate

Wen, Rui‐Tao; Niklasson, Gunnar A.; Granqvist, Claes G.

doi:10.1016/j.solmat.2013.08.035

Cited by 32 publications

(20 citation statements)

References 33 publications

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“…Subsequent amounts of charge insertion and extraction differ by a constant value of ~1.4 mC/cm 2 after the fourth CV cycle, and these amounts decline monotonically upon extended voltammetric cycling, which points at irreversible electrochemical reactions leading to continuous sample degradation. We note that no similar effect was found for CV cycling in the 2.0 -4.7 V vs Li/Li + range for our earlier study of Iroxide-based films [74]. The overall shapes of the curves are similar to those in Fig.…”

Section: Nickel Oxide Films In Li-pc: Electrochemical Optical and Stsupporting

confidence: 71%

“…V vs Li/Li + which, importantly, was chosen to be the same as in our earlier investigation of Ir oxide films [74]. The voltage sweep rate was 10 mV/s, except for studies of long-term cycling durability when it was 50 mV/s.…”

Section: Elemental Compositions and Atomic Concentrations Were Determmentioning

confidence: 99%

“…The present paper lays a foundation for a comprehensive investigation of electrochromism in the Ni-Ir oxide system-with a scope that is similar to the one in our recent work on the electrochromism in the full Ni-W system [23,25,[71][72][73]-but is of interest also in its own right. Data on pure Ir oxide immersed in propionic acid, potassium hydroxide (KOH), and lithium perchlorate in propylene carbonate (Li-PC) were presented recently [74]. Below we investigate pure Ni oxide in KOH and Li-PC under experimental conditions that were carefully chosen in order to allow direct comparison with data on Ir oxide (propionic acid was not considered since Ni oxide is not stable in acids).…”

Section: Introductionmentioning

confidence: 99%

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Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide: Power-law decay of the charge density exchange

Wen

Granqvist

Niklasson

2014

Applied Physics Letters

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Porous nickel oxide films were deposited onto unheated indium tin oxide coated glass substrates by reactive dc magnetron sputtering. These films had a cubic NiO structure.Electrochromic properties were evaluated in 1 M potassium hydroxide (KOH) and in 1 M lithium perchlorate in propylene carbonate (Li-PC). Large optical modulation was obtained for ~500-nm-thick films both in KOH and in Li-PC (~70 % and ~50 % at 550 nm, respectively). In KOH, tensile and compressive stress, due to expansion and contraction of the lattice, were found for films in their bleached and colored state, respectively. In Li-PC, compressive stress was seen both in colored and bleached films. Durability tests with voltage sweeps between -0.5 to 0.65 V vs Ag/AgCl in KOH showed good durability for 10,000 cycles, whereas voltage sweeps between 2.0 to 4.7 V vs Li/Li + in Li-PC yielded significant degradation after 1000 cycles.

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Section: Nickel Oxide Films In Li-pc: Electrochemical Optical and Stsupporting

confidence: 71%

Section: Elemental Compositions and Atomic Concentrations Were Determmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide: Power-law decay of the charge density exchange

Wen

Granqvist

Niklasson

2014

Applied Physics Letters

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“…18 Thus we surmise that the increased charge density in the latter film is due to a contribution from Ir occurring primarily below 2.7 V. Enhanced charge density becomes even more pronounced for still larger Ir contents in the films (not shown). Optical transmittance spectra revealed that the optical modulation (T bleached -T colored )…”

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confidence: 72%

Strongly Improved Electrochemical Cycling Durability by Adding Iridium to Electrochromic Nickel Oxide Films

Wen

Niklasson

Granqvist

2015

ACS Appl. Mater. Interfaces

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Anodically coloring Ni oxide thin films are of much interest as counter electrodes in Woxide-based electrochromic devices such as "smart windows" for energy efficient buildings.However, Ni oxide films are prone to suffer severe charge density degradation upon prolonged electrochemical cycling, which can lead to insufficient device lifetime. Therefore means to improve the durability of Ni-oxide-based films is an important challenge at present.Here we report that the incorporation of a modest amount of Ir into Ni oxide films [Ir/(Ir + Ni) = 7.6 at.%] leads to remarkable durability, exceeding 10,000 cycles in a Li-conducting 2 electrolyte, along with significantly improved optical modulation during extended cycling.Structure characterization showed that the fcc-type NiO structure remained after Ir addition.Moreover, the crystallinity of these films was enhanced upon electrochemical cycling. 3Electrochromic thin-film devices are of much current interest for "smart windows" capable of varying their throughput of visible light and solar energy so that buildings can be rendered both energy efficient and comfortable. 1-3 These devices normally utilize joint transport of small ions and electrons between a thin film of tungsten oxide and a counter electrode based on nickel oxide, basically in the same way as in an electrical battery, and the optical transmittance is low when the charge resides in W oxide while the transmittance is high when the charge is in Ni oxide. Ni oxide films suffer from optical degradation and limitation in modulation span under extended electrochemical cycling, 4-6 and several recent studies aimed at alleviating these deficiencies have been reported. Beneficial effects of additives to the Ni oxide have been studied, specifically for Li, 7,8 C, 9,10 N, 11 W, 12 (Li,W), 13 (Li,Al), 14 (Li,Zr), 15 and several more. Nevertheless, the most crucial problem for Ni-oxide-based films, viz., their cycling durability, is still far from solved. In a previous paper, 4 we showed that the degradation of charge density in Ni-oxide follows a power-law decay model upon cycling in 1 M LiClO 4 dissolved in propylene carbonate (Li-PC), and long-term degradation hence does not only curtail cycle-life but also gradually erodes the optical modulation span of the device.In this Letter, we report that the charge density exchange in Ni-oxide-based thin films can be significantly increased during extended electrochemical cycling if the films contain a modest amount of iridium, and optical modulation is concomitantly enhanced.We deposited Ir-Ni oxide films by co-sputtering from metallic iridium and nickel targets in argon-oxygen atmosphere onto unheated glass coated with In 2 O 3 :Sn (i.e., ITO, 60 Ω/square).Films were also prepared on carbon substrates for composition determination. Film thickness t was determined by surface profilometry across a step edge. The iridium content in the Ni oxide was characterized by Rutherford backscattering spectroscopy (RBS). Ni oxide before and after 10,000 and 2,600 CV cycles, respe...

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“…Transition metals based on metal-organic complex multicolor electrochromic materials exhibit attractive properties, such as high stability and chemiluminescence. 16 However, the expense and scarcity of the precious metals, such as ruthenium, 15,16 osmium 17 and iridium, 18 limit their practical applications. Polymeric multicolor electrochromic materials with different electrochromic activation units [19][20][21] possess the advantages of easy processing, diverse resources and facile color tunability.…”

Section: Introductionmentioning

confidence: 99%

A single-molecule multicolor electrochromic device generated through medium engineering

et al. 2015

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Multicolor organic electrochromic materials are important for the generation of full-color devices. However, achieving multiple colors using a single-molecule material has proved challenging. In this study, a multicolor electrochromic prototype device is generated by integrating medium engineering/in situ 'electro base'/laminated electrode technologies with the simple flying fish-shaped methyl ketone TM1. This multicolor electrochromic (green, blue and magenta) device is durable and has a high coloration efficiency (350 cm 2 C 21 ), a fast switching time (50 ms) and superior reversibility. This study is a successful attempt to integrate solvatochromism and basochromism in an electronic display. This integration not only introduces a new avenue for color tuning, in addition to the structural design of the colorant, but will also inspire further developments in the tuning of many other properties by this medium engineering approach, such as conductance and the redox property, and thereby accelerate versatile applications in data recording, ultrathin flexible displays, and optical communication and sensing. Keywords: electrochromic materials; laminated electrodes; microenvironment; multicolor devices; solvatochromic materials INTRODUCTION Owing to the increasing demand for low-power, ultrathin, flexible electronic displays, organic electrochromic materials 1-3 have become a research focus because of their distinct merits: low weight, high contrast, wide viewing angle, flexibility and the potential for low power consumption. Because the realization of a multicolor switch is preferred in the majority of their applications in displays, 4-10 various electrochromic materials including polymers, 11,12 small organic molecules 13,14 and metal-organic complexes, 15 and technologies aimed at multicolor switches have been intensively explored. Transition metals based on metal-organic complex multicolor electrochromic materials exhibit attractive properties, such as high stability and chemiluminescence. 16 However, the expense and scarcity of the precious metals, such as ruthenium, 15,16 osmium 17 and iridium, 18 limit their practical applications. Polymeric multicolor electrochromic materials with different electrochromic activation units [19][20][21] possess the advantages of easy processing, diverse resources and facile color tunability. However, some intrinsic problems, such as the lack of colorless states, poor transparency, poor color purity and complicated synthesis procedures, hinder their applications. Compared with electrochromic polymers, small organic color switches possess the advantages of low cost, good color purity, distinct transition from colorless to colored states and fine tunability of their photoelectronic properties via easy structure modifications. The lack of multicolor abilities is their intrinsic

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Electrochromic iridium oxide films: Compatibility with propionic acid, potassium hydroxide, and lithium perchlorate in propylene carbonate

Cited by 32 publications

References 33 publications

Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide: Power-law decay of the charge density exchange

Cyclic voltammetry on sputter-deposited films of electrochromic Ni oxide: Power-law decay of the charge density exchange

Strongly Improved Electrochemical Cycling Durability by Adding Iridium to Electrochromic Nickel Oxide Films

A single-molecule multicolor electrochromic device generated through medium engineering

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