Abstract

This study focuses on the electrochromic device (ECD) applications of poly(3,4-ethylenedioxythiophene)/tungsten oxide (PEDOT/WO3) hybrid nanofibers prepared via electrospinning method. Nanoporous WO3 films were initially electrosynthesized on Pt sheet. The PEDOT layer was electropolymerized onto the entire surface of the WO3 nanoporous host framework in the presence of different ionic liquids: 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), 1-butyl- 3-methylimidazolium bis(trifluoromethylsulfonyl) imide (BMIMTFSI), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI). ECDs changed color reversibly from transparent to light brown by switching from +3 V to -3 V. It was found that the highest optical modulation of 47.89% and maximum coloration efficiency of 363.72 cm2/C is achieved for PEDOT/WO3/BMIMPF6 based electrochromic device. Hybrid nanofibers exhibited excellent long term stability even after 1000 chronoamperometric cycles.

References

[1] Reyes-Gil K. R., Stephens Z. D., Stavila V., Robinson D. B. Composite WO3/TiO2Nanostructures for High Electrochromic Activity. ACS Appl. Mater. Interfaces 2015, 7,2202−2213.
[2] Yu W., Chen J., Fu Y. Electrochromic property of a copolymer based on 5-cyanoindole and3,4-ethylenedioxythiophene and its application in electrochromic devices. Journal ofElectroanalytical Chemistry 2013, 700, 17–23.
[3] Zhang J., Tu J., Du G., Dong Z. Ultra-thin WO3 nanorod embedded polyaniline compositethin film: Synthesis and electrochromic characteristics. Solar Energy Materials & Solar Cells2013, 114, 31–37.
[4] Kim T., Jeon H. J., Lee J., Nah. Y. Enhanced electrochromic properties of hybrid P3HT/WO3composites with multiple colorations. Electrochem. Commun. 2015, 57, 65–69.
[5] Granqvist C.G., Tungsten oxide films: Preparation, structure, and composition of sputterdeposited films, in: C.G. Granqvist (Ed.), Handbook of Inorganic Electrochromic Materials,Elsevier Science B.V., Amsterdam 1995, Chapter 4, pp 55–63.
[6] Baek Y., Yong K. Controlled growth and characterization of tungsten oxide nanowiresusing thermal evaporation of WO3 powder. J. Phys. Chem. C 2007, 111, 1213–1218.
[7] Wang J.M., Khoo E., Lee P.S., Ma J. Controlled Synthesis of WO3 Nanorods and TheirElectrochromic Properties in H2SO4 Electrolyte. J. Phys. Chem. C 2009, 113, 9655–9658.
[8] Zhang J., Wang X.L., Xia X.H., Gu C.D. Electrochromic behavior of WO3 nanotree filmsprepared by hydrothermal oxidation. Solar Energy Materials and Solar Cells 2011, 95, 2107–2112.
[9] Baeck S.H., Choi K.S., Jaramillo T.F., Stucky G.D., McFarland E.W. Enhancement ofphotocatalytic and electrochromic properties of electrochemically fabricated mesoporous WO3thin films. Adv. Mater. 2003, 15, 1269–1273.
[10] Dulgerbaki C., Maslakci Nohut N., Komur A. I., Oksuz Uygun A. Electrochromic devicebased on electrospun WO3 nanofibers. Materials Research Bulletin 2015, 72, 70–76.
[11] Leftheriotis G., Yianoulis P. Development of electrodeposited WO3 films with modifiedsurface morphology and improved electrochromic properties. Solid State Ionics 2008, 179, 2192–2197.
[12] Kondalkar V.V., Kharade R.R., Mali S.S., Mane R.M. Nanobrick-like WO3 thin films:Hydrothermal synthesis and electrochromic application. Superlattices and Microstructures 2014,73, 290–295.
[13] Liao C.C., Chen F.R., Kai J.J. WO3_x nanowires based electrochromic devices. SolarEnergy Materials & Solar Cells 2006, 90, 1147–1155.
[14] Wang K., Zeng P., Zhai J., Liu Q. Electrochromic films with a stacked structure of WO3nanosheets. Electrochemistry Communications 2013, 26, 5–9.
[15] Shim H.S., Kim J.W., Sung Y.E., Kim W.B. Electrochromic properties of tungsten oxidenanowires fabricated by electrospinning method. Solar Energy Materials & Solar Cells 2009 93,2062–2068
[16] Chen Z., Lv H., Zhu X., Li D. Electropolymerization of Aniline onto Anodic WO3 Film: AnApproach to Extend Polyaniline Electroactivity Beyond pH 7. J. Phys. Chem. C 2014, 118,27449−27458.
[17] Ling H., Liu L., Lee P.S., Lu X. Layer-by-Layer Assembly of PEDOT:PSS and WO3Nanoparticles: Enhanced Electrochromic Coloration Efficiency and Mechanism Studies byScanning Electrochemical Microscopy. Electrochimica Acta 2015, 174, 57–65.
[18] Wei H., Yan X., Wu S., Luo Z. Electropolymerized Polyaniline Stabilized Tungsten OxideNanocomposite Films: Electrochromic Behavior and Electrochemical Energy Storage. J. Phys.Chem. C 2012, 116, 25052−25064.
[19] Cai G.F., Tu J.P., Zhou D. Dual electrochromic film based on WO3/polyaniline core/shellnanowire array. Solar Energy Materials&Solar Cells 2014, 122, 51–58.
[20] Feng Z., Mo D., Wang Z. Low-potential electrosynthesis of a novel nitrogen analog ofPEDOT in an ionic liquid and its optoelectronic properties. Electrochimica Acta 2015, 160, 160–168.
[21] Ahmad S., Deepa M., Singh S. Electrochemical Synthesis and Surface Characterization ofPoly(3,4-ethylenedioxythiophene) Films Grown in an Ionic Liquid. Langmuir 2007, 23, 11430-11433.
[22] Ma L.J., Li Y.X., Yu X.F. Using room temperature ionic liquid to fabricate PEDOT/TiO2nanocomposite electrode-based electrochromic devices with enhanced long-term stability, SolarEnergy Materials & Solar Cells 2008, 92, 1253-1259.
[23] Dulgerbaki C., Oksuz Uygun A. Efficient Electrochromic Materials Based on PEDOT/WO3Composites Synthesized in Ionic Liquid Media. Electroanal. 2014, 26, 2501–2512.
[24] Dulgerbaki C., Oksuz Uygun A. Fabricating polypyrrole/tungsten oxide hybrid basedelectrochromic devices using different ionic liquids. Polym. Adv. Technol. 2015, DOI:10.1002/pat.3601
[25] Tong L. Nanofibers - production, properties and functional applications 2011, InTech,Rijeka, Croatia.
[26] Liang L., Zhang J., Zhou Y., Xie J., Zhang X., Guan M., Pan B., Xie Y. High-performanceflexible electrochromic device based on facile semiconductor-to-metal transition realized byWO3.2H2O ultrathin nanosheets. Sci. Rep. 2013, 3, 1936; DOI:10.1038/srep01936
[27] Xu C., Zhao J., Yu J. Ethylenedioxythiophene derivatized polynapthalenes as activematerials for electrochromic devices. Electrochimica Acta 2013, 96, 82–89.
[28] Janaky C., Tacconi N. R. Electrodeposited Polyaniline in a Nanoporous WO3 Matrix: AnOrganic/Inorganic Hybrid Exhibiting Both p- and n-Type Photoelectrochemical Activity. J. Phys.Chem. C 2012, 116, 4234−4242.
[29] Wen R.T., Niklasson G.A., Granqvist C.G. Strongly Improved Electrochemical CyclingDurability by Adding Iridium to Electrochromic Nickel Oxide Films. ACS Appl. Mater.Interfaces 2015, 7, 9319−9322.
[30] Alcaraz-Espinoza J.J., Chávez-Guajardo A.E, Melo C.P. Hierarchical CompositePolyaniline−(Electrospun Polystyrene) Fibers Applied to Heavy Metal Remediation. ACS Appl.Mater. Interfaces 2015, 7, 7231−7240.
[31] Liao Y., Zhang C., Zhang Y., Strong V. Carbon Nanotube/Polyaniline CompositeNanofibers: Facile Synthesis and Chemosensors. Nano Lett. 2011, 11, 954–959.
[32] Erro E. M., Baruzzi A. M., Iglesias R. A., Fast electrochromic response of ultraporouspolyaniline nanofibers. Polymer 2014, 55, 2440-2444.