Abstract

New security devices based on innovative technologies and ideas are essential in order to limit counterfeiting’s profound impact on our economy and society. Interference security image structures have been in circulation for more than 20 years, but commercially available iridescent products now represent a potential threat. Therefore, the introduction of active materials, such as electrochromic WO3, to present-day optical security devices offers interesting possibilities. We have previously proposed electrochromic interference filters based on porous and dense WO3, which possessed an angle-dependent and voltage-driven color shift. However, the low index contrast required filters with a high number of layers. In this article, we increase the index contrast (0.61) by mixing WO3 with SiO2 and study the physical and electrochromic properties of mixtures. We next combine high and low index films in tandem configurations to observe the bleaching/coloration dynamics. To account for the film performance, we propose a simple explanation based on the differences in electron diffusion coefficients. An 11 layer electrochromic interference filter (EIF) based on the alternation of pure WO3 and (WO3)0.17(SiO2)0.83 films with a blue to purple angular color shift is then presented. Finally, we discuss possible applications of these EIFs for security.

© 2012 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef]
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  33. A. E. Aliev and C. Park, “Development of WO3  thin films using nanoscale silicon particles,” Jpn. J. Appl. Phys. 39, 3572–3578 (2000).
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    [CrossRef]
  35. E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
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    [CrossRef]
  38. A. Lusis, J. Kleperis, and E. Pentjušs, “Model of electrochromic and related phenomena in tungsten oxide thin films,” J. Solid State Electrochem. 7, 106–112 (2003).
  39. D.-J. Kim and S.-I. Pyun, “Hydrogen transport through rf-magnetron sputtered amorphous WO3 film with three kinds of hydrogen injection sites,” Solid State Ion. 99, 185–192 (1997).
    [CrossRef]
  40. B. W. Faughnan, R. S. Crandall, and M. A. Lampert, “Model for the bleaching of WO3 electrochromic films by an electric field,” Appl. Phys. Lett. 27, 275–277 (1975).
    [CrossRef]
  41. C. G. Granqvist, “Progress in electrochromics: tungsten oxide revisited,” Electrochim. Acta 44, 3005–3015 (1999).
    [CrossRef]
  42. J. Wang and J. M. Bell, “The kinetic behaviour of ion injection in WO3 based films produced by sputter and sol-gel deposition: Part II. Diffusion coefficients,” Sol. Energy Mater. Sol. Cells 58, 411–429 (1999).
    [CrossRef]
  43. M. Denesuk and D. R. Uhlmann, “Site-saturation model for the optical efficiency of tungsten oxide-based devices,” J. Electrochem. Soc. 143, L186–L188 (1996).
    [CrossRef]
  44. J.-G. Zhang, C. E. Tracy, D. K. Benson, and S. K. Deb, “The influence of microstructure on the electrochromic properties of LixWO3 thin films: Part I. Ion diffusion and electrochromic properties,” J. Mater. Res. 8, 2649–2656 (1993).
    [CrossRef]
  45. O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
    [CrossRef]
  46. S. K. Deb and H. Witzke, “The solid state electrochromic phenomenon and its applications to display devices,” in Proceedings of IEEE Conference on International Electron Devices Meeting (IEEE, 1975), pp. 393–397.
  47. R. W. Phillips and A. F. Bleikolm, “Optical coatings for document security,” Appl. Opt. 35, 5529–5534 (1996).
    [CrossRef]
  48. S. K. Deb, “Reminiscences on the discovery of electrochromic phenomena in transition metal oxides,” Sol. Energy Mater. Sol. Cells 39, 191–201 (1995).
    [CrossRef]
  49. I. Shimizu, M. Shizukuishi, and E. Inoue, “Solid-state electrochromic device consisting of amorphous WO3 and Cr2O3,” J. Appl. Phys. 50, 4027–4032 (1979).
    [CrossRef]

2011

D. Li, G. Wu, G. Gao, J. Shen, and F.-Q. Huang, “Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2gasochromic films doped with Pd catalyst,” ACS Appl. Mater. Interfaces 3, 4573–4579 (2011).
[CrossRef]

B. Baloukas, J.-M. Lamarre, and L. Martinu, “Active metameric security devices using an electrochromic material,” Appl. Opt. 50, C41–C49 (2011).
[CrossRef]

B. Baloukas, J.-M. Lamarre, and L. Martinu, “Electrochromic interference filters fabricated from dense and porous tungsten oxide films,” Sol. Energy Mater. Sol. Cells 95, 807–815 (2011).
[CrossRef]

2008

S. Larouche and L. Martinu, “Openfilters: open-source software for the design, optimization, and synthesis of optical filters,” Appl. Opt. 47, C219–C230 (2008).
[CrossRef]

F. Messina, M. Cannas, and R. Boscaino, “Generation of defects in amorphous SiO2 assisted by two-step absorption on impurity sites,” J. Phys. Condens. Matter 20, 275210 (2008).
[CrossRef]

D. Saygin-Hinczewski, M. Hinczewski, I. Sorar, F. Z. Tepehan, and G. G. Tepehan, “Modeling the optical properties of WO3 and WO3-SiO2 thin films,” Sol. Energy Mater. Sol. Cells 92, 821–829 (2008).
[CrossRef]

B. Baloukas and L. Martinu, “Metameric interference security image structures,” Appl. Opt. 47, 1585–1593 (2008).
[CrossRef]

2007

N. Naseri, R. Azimirad, O. Akhavan, and A. Z. Moshfegh, “The effect of nanocrystalline tungsten oxide concentration on surface properties of dip-coated hydrophilic WO3-SiO2 thin films,” J. Phys. D 40, 2089–2095 (2007).
[CrossRef]

2005

2004

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “The effect of water on the electrochromic properties of WO3 films prepared by vacuum and chemical methods,” Sol. Energy Mater. Sol. Cells 83, 115–124 (2004).
[CrossRef]

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

S. Larouche, H. Szymanowski, J. E. Klemberg-Sapieha, L. Martinu, and S. C. Gujrathi, “Microstructure of plasma-deposited SiO2/TiO2 optical films,” J. Vac. Sci. Technol. A 22, 1200–1207 (2004).
[CrossRef]

2003

A. Lusis, J. Kleperis, and E. Pentjušs, “Model of electrochromic and related phenomena in tungsten oxide thin films,” J. Solid State Electrochem. 7, 106–112 (2003).

2002

X. Q. Xu, H. Shen, and X. Y. Xiong, “Gasochromic effect of sol-gel WO3−SiO2 films with evaporated platinum catalyst,” Thin Solid Films 415, 290–295 (2002).
[CrossRef]

2001

M. Greissel, “The colors they are a-changin’,” Indust. Paint Powder 77, 16–18 (2001).

S. Papaefthimiou, G. Leftheriotis, and P. Yianoulis, “Study of WO3 films with textured surfaces for improved electrochromic performance,” Solid State Ion. 139, 135–144 (2001).
[CrossRef]

2000

A. E. Aliev and C. Park, “Development of WO3  thin films using nanoscale silicon particles,” Jpn. J. Appl. Phys. 39, 3572–3578 (2000).
[CrossRef]

1999

P. M. S. Monk, “Charge movement through electrochromic thin-film tungsten trioxide,” Crit. Rev. Solid State Mater. Sci. 24, 193–226 (1999).
[CrossRef]

E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
[CrossRef]

C. G. Granqvist, “Progress in electrochromics: tungsten oxide revisited,” Electrochim. Acta 44, 3005–3015 (1999).
[CrossRef]

J. Wang and J. M. Bell, “The kinetic behaviour of ion injection in WO3 based films produced by sputter and sol-gel deposition: Part II. Diffusion coefficients,” Sol. Energy Mater. Sol. Cells 58, 411–429 (1999).
[CrossRef]

1998

M. Klisch, “12-tungstosilicic acid (12-TSA) as a tungsten precursor in alcoholic solution for deposition of xWO3(1−x)SiO2 thin films (x<0.7) exhibiting electrochromic coloration ability,” J. Sol-Gel Sci. Technol. 12, 21–33(1998).
[CrossRef]

1997

D.-J. Kim and S.-I. Pyun, “Hydrogen transport through rf-magnetron sputtered amorphous WO3 film with three kinds of hydrogen injection sites,” Solid State Ion. 99, 185–192 (1997).
[CrossRef]

1996

R. W. Phillips and A. F. Bleikolm, “Optical coatings for document security,” Appl. Opt. 35, 5529–5534 (1996).
[CrossRef]

M. Denesuk and D. R. Uhlmann, “Site-saturation model for the optical efficiency of tungsten oxide-based devices,” J. Electrochem. Soc. 143, L186–L188 (1996).
[CrossRef]

G. E. Jellison and F. A. Modine, “Parametrization of the optical functions of amorphous materials in the interband region,” Appl. Phys. Lett. 69, 371–373 (1996).
[CrossRef]

1995

S. K. Deb, “Reminiscences on the discovery of electrochromic phenomena in transition metal oxides,” Sol. Energy Mater. Sol. Cells 39, 191–201 (1995).
[CrossRef]

1993

J.-G. Zhang, C. E. Tracy, D. K. Benson, and S. K. Deb, “The influence of microstructure on the electrochromic properties of LixWO3 thin films: Part I. Ion diffusion and electrochromic properties,” J. Mater. Res. 8, 2649–2656 (1993).
[CrossRef]

1992

S. C. Gujrathi and S. Bultena, “Depth profiling of hydrogen using the high efficiency ERD-TOF technique,” Nucl. Instrum. Methods Phys. Res. Sect. B 64, 789–795 (1992).
[CrossRef]

1989

1986

J. A. Thornton, “The microstructure of sputter-deposited coatings,” J. Vac. Sci. Technol. A 4, 3059–3065 (1986).
[CrossRef]

S. A. Agnihotry, K. K. Saini, T. K. Saxena, and S. Chandra, “Electical properties and morphology of obliquely deposited electrochromic WO3 films,” Thin Solid Films 141, 183–192 (1986).
[CrossRef]

1984

H. Morita and H. Washida, “Electrochromism of atmospheric evaporated tungsten oxide films (AETOF),” Jpn. J. Appl. Phys. 23, 754–759 (1984).
[CrossRef]

1982

D. E. Aspnes, “Optical properties of thin films,” Thin Solid Films 89, 249–262 (1982).
[CrossRef]

1979

C. W. Peterson, J. Parlett, and R. S. Crandall, “The physics of electrochromism: an advanced laboratory experiment,” Am. J. Phys. 47, 772–775 (1979).
[CrossRef]

T. Jow and J. B. Wagner, “The effect of dispersed alumina particles on the electrical conductivity of cuprous chloride,” J. Electrochem. Soc. 126, 1963–1972 (1979).
[CrossRef]

I. Shimizu, M. Shizukuishi, and E. Inoue, “Solid-state electrochromic device consisting of amorphous WO3 and Cr2O3,” J. Appl. Phys. 50, 4027–4032 (1979).
[CrossRef]

1977

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

1975

B. W. Faughnan, R. S. Crandall, and M. A. Lampert, “Model for the bleaching of WO3 electrochromic films by an electric field,” Appl. Phys. Lett. 27, 275–277 (1975).
[CrossRef]

R. S. Crandall and B. W. Faughnan, “Measurement of the diffusion coefficient of electrons in WO3 films,” Appl. Phys. Lett. 26, 120–121 (1975).
[CrossRef]

Adamik, M.

E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
[CrossRef]

Agnihotry, S. A.

S. A. Agnihotry, K. K. Saini, T. K. Saxena, and S. Chandra, “Electical properties and morphology of obliquely deposited electrochromic WO3 films,” Thin Solid Films 141, 183–192 (1986).
[CrossRef]

Akhavan, O.

N. Naseri, R. Azimirad, O. Akhavan, and A. Z. Moshfegh, “The effect of nanocrystalline tungsten oxide concentration on surface properties of dip-coated hydrophilic WO3-SiO2 thin films,” J. Phys. D 40, 2089–2095 (2007).
[CrossRef]

Aliev, A. E.

A. E. Aliev and C. Park, “Development of WO3  thin films using nanoscale silicon particles,” Jpn. J. Appl. Phys. 39, 3572–3578 (2000).
[CrossRef]

Aspnes, D. E.

D. E. Aspnes, “Optical properties of thin films,” Thin Solid Films 89, 249–262 (1982).
[CrossRef]

Azimirad, R.

N. Naseri, R. Azimirad, O. Akhavan, and A. Z. Moshfegh, “The effect of nanocrystalline tungsten oxide concentration on surface properties of dip-coated hydrophilic WO3-SiO2 thin films,” J. Phys. D 40, 2089–2095 (2007).
[CrossRef]

Baloukas, B.

Baur, G.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Bell, J. M.

J. Wang and J. M. Bell, “The kinetic behaviour of ion injection in WO3 based films produced by sputter and sol-gel deposition: Part II. Diffusion coefficients,” Sol. Energy Mater. Sol. Cells 58, 411–429 (1999).
[CrossRef]

Benson, D. K.

J.-G. Zhang, C. E. Tracy, D. K. Benson, and S. K. Deb, “The influence of microstructure on the electrochromic properties of LixWO3 thin films: Part I. Ion diffusion and electrochromic properties,” J. Mater. Res. 8, 2649–2656 (1993).
[CrossRef]

Bleikolm, A. F.

Boscaino, R.

F. Messina, M. Cannas, and R. Boscaino, “Generation of defects in amorphous SiO2 assisted by two-step absorption on impurity sites,” J. Phys. Condens. Matter 20, 275210 (2008).
[CrossRef]

Brandt, G.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Bultena, S.

S. C. Gujrathi and S. Bultena, “Depth profiling of hydrogen using the high efficiency ERD-TOF technique,” Nucl. Instrum. Methods Phys. Res. Sect. B 64, 789–795 (1992).
[CrossRef]

Cannas, M.

F. Messina, M. Cannas, and R. Boscaino, “Generation of defects in amorphous SiO2 assisted by two-step absorption on impurity sites,” J. Phys. Condens. Matter 20, 275210 (2008).
[CrossRef]

Chandra, S.

S. A. Agnihotry, K. K. Saini, T. K. Saxena, and S. Chandra, “Electical properties and morphology of obliquely deposited electrochromic WO3 films,” Thin Solid Films 141, 183–192 (1986).
[CrossRef]

Crandall, R. S.

C. W. Peterson, J. Parlett, and R. S. Crandall, “The physics of electrochromism: an advanced laboratory experiment,” Am. J. Phys. 47, 772–775 (1979).
[CrossRef]

R. S. Crandall and B. W. Faughnan, “Measurement of the diffusion coefficient of electrons in WO3 films,” Appl. Phys. Lett. 26, 120–121 (1975).
[CrossRef]

B. W. Faughnan, R. S. Crandall, and M. A. Lampert, “Model for the bleaching of WO3 electrochromic films by an electric field,” Appl. Phys. Lett. 27, 275–277 (1975).
[CrossRef]

Cullity, B. D.

B. D. Cullity, Elements or X-Ray Diffraction, 2nd ed.(Addisson-Wesley, 1979).

Dautzenberg, G.

E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
[CrossRef]

Deb, S. K.

S. K. Deb, “Reminiscences on the discovery of electrochromic phenomena in transition metal oxides,” Sol. Energy Mater. Sol. Cells 39, 191–201 (1995).
[CrossRef]

J.-G. Zhang, C. E. Tracy, D. K. Benson, and S. K. Deb, “The influence of microstructure on the electrochromic properties of LixWO3 thin films: Part I. Ion diffusion and electrochromic properties,” J. Mater. Res. 8, 2649–2656 (1993).
[CrossRef]

S. K. Deb and H. Witzke, “The solid state electrochromic phenomenon and its applications to display devices,” in Proceedings of IEEE Conference on International Electron Devices Meeting (IEEE, 1975), pp. 393–397.

Denesuk, M.

M. Denesuk and D. R. Uhlmann, “Site-saturation model for the optical efficiency of tungsten oxide-based devices,” J. Electrochem. Soc. 143, L186–L188 (1996).
[CrossRef]

DiNunzio, L. A.

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

Dobrowolski, J. A.

Faughnan, B. W.

R. S. Crandall and B. W. Faughnan, “Measurement of the diffusion coefficient of electrons in WO3 films,” Appl. Phys. Lett. 26, 120–121 (1975).
[CrossRef]

B. W. Faughnan, R. S. Crandall, and M. A. Lampert, “Model for the bleaching of WO3 electrochromic films by an electric field,” Appl. Phys. Lett. 27, 275–277 (1975).
[CrossRef]

Gao, G.

D. Li, G. Wu, G. Gao, J. Shen, and F.-Q. Huang, “Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2gasochromic films doped with Pd catalyst,” ACS Appl. Mater. Interfaces 3, 4573–4579 (2011).
[CrossRef]

Gilbert, L.

R. Padiyath, C. Haak, and L. Gilbert, “Spectrally selective window films,” in 50th Annual Technical Conference of the Society of Vacuum Coaters (Society of Vacuum Coaters, 2007), pp. 669–673.

Granqvist, C. G.

C. G. Granqvist, “Progress in electrochromics: tungsten oxide revisited,” Electrochim. Acta 44, 3005–3015 (1999).
[CrossRef]

C. G. Granqvist, Handbook of Inorganic Electrochromic Materials (Elsevier, 1995).

Greissel, M.

M. Greissel, “The colors they are a-changin’,” Indust. Paint Powder 77, 16–18 (2001).

Grilli, M. L.

E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
[CrossRef]

Gujrathi, S. C.

S. Larouche, H. Szymanowski, J. E. Klemberg-Sapieha, L. Martinu, and S. C. Gujrathi, “Microstructure of plasma-deposited SiO2/TiO2 optical films,” J. Vac. Sci. Technol. A 22, 1200–1207 (2004).
[CrossRef]

S. C. Gujrathi and S. Bultena, “Depth profiling of hydrogen using the high efficiency ERD-TOF technique,” Nucl. Instrum. Methods Phys. Res. Sect. B 64, 789–795 (1992).
[CrossRef]

Haak, C.

R. Padiyath, C. Haak, and L. Gilbert, “Spectrally selective window films,” in 50th Annual Technical Conference of the Society of Vacuum Coaters (Society of Vacuum Coaters, 2007), pp. 669–673.

Hinczewski, M.

D. Saygin-Hinczewski, M. Hinczewski, I. Sorar, F. Z. Tepehan, and G. G. Tepehan, “Modeling the optical properties of WO3 and WO3-SiO2 thin films,” Sol. Energy Mater. Sol. Cells 92, 821–829 (2008).
[CrossRef]

Ho, F. C.

Huang, F.-Q.

D. Li, G. Wu, G. Gao, J. Shen, and F.-Q. Huang, “Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2gasochromic films doped with Pd catalyst,” ACS Appl. Mater. Interfaces 3, 4573–4579 (2011).
[CrossRef]

Inoue, E.

I. Shimizu, M. Shizukuishi, and E. Inoue, “Solid-state electrochromic device consisting of amorphous WO3 and Cr2O3,” J. Appl. Phys. 50, 4027–4032 (1979).
[CrossRef]

Jellison, G. E.

G. E. Jellison and F. A. Modine, “Parametrization of the optical functions of amorphous materials in the interband region,” Appl. Phys. Lett. 69, 371–373 (1996).
[CrossRef]

Jerman, M.

Jow, T.

T. Jow and J. B. Wagner, “The effect of dispersed alumina particles on the electrical conductivity of cuprous chloride,” J. Electrochem. Soc. 126, 1963–1972 (1979).
[CrossRef]

Kim, D.-J.

D.-J. Kim and S.-I. Pyun, “Hydrogen transport through rf-magnetron sputtered amorphous WO3 film with three kinds of hydrogen injection sites,” Solid State Ion. 99, 185–192 (1997).
[CrossRef]

Klemberg-Sapieha, J. E.

S. Larouche, H. Szymanowski, J. E. Klemberg-Sapieha, L. Martinu, and S. C. Gujrathi, “Microstructure of plasma-deposited SiO2/TiO2 optical films,” J. Vac. Sci. Technol. A 22, 1200–1207 (2004).
[CrossRef]

Kleperis, J.

A. Lusis, J. Kleperis, and E. Pentjušs, “Model of electrochromic and related phenomena in tungsten oxide thin films,” J. Solid State Electrochem. 7, 106–112 (2003).

Klisch, M.

M. Klisch, “12-tungstosilicic acid (12-TSA) as a tungsten precursor in alcoholic solution for deposition of xWO3(1−x)SiO2 thin films (x<0.7) exhibiting electrochromic coloration ability,” J. Sol-Gel Sci. Technol. 12, 21–33(1998).
[CrossRef]

Lamarre, J.-M.

B. Baloukas, J.-M. Lamarre, and L. Martinu, “Electrochromic interference filters fabricated from dense and porous tungsten oxide films,” Sol. Energy Mater. Sol. Cells 95, 807–815 (2011).
[CrossRef]

B. Baloukas, J.-M. Lamarre, and L. Martinu, “Active metameric security devices using an electrochromic material,” Appl. Opt. 50, C41–C49 (2011).
[CrossRef]

Lampert, M. A.

B. W. Faughnan, R. S. Crandall, and M. A. Lampert, “Model for the bleaching of WO3 electrochromic films by an electric field,” Appl. Phys. Lett. 27, 275–277 (1975).
[CrossRef]

Larouche, S.

S. Larouche and L. Martinu, “Openfilters: open-source software for the design, optimization, and synthesis of optical filters,” Appl. Opt. 47, C219–C230 (2008).
[CrossRef]

S. Larouche, H. Szymanowski, J. E. Klemberg-Sapieha, L. Martinu, and S. C. Gujrathi, “Microstructure of plasma-deposited SiO2/TiO2 optical films,” J. Vac. Sci. Technol. A 22, 1200–1207 (2004).
[CrossRef]

Leftheriotis, G.

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “The effect of water on the electrochromic properties of WO3 films prepared by vacuum and chemical methods,” Sol. Energy Mater. Sol. Cells 83, 115–124 (2004).
[CrossRef]

S. Papaefthimiou, G. Leftheriotis, and P. Yianoulis, “Study of WO3 films with textured surfaces for improved electrochromic performance,” Solid State Ion. 139, 135–144 (2001).
[CrossRef]

Li, D.

D. Li, G. Wu, G. Gao, J. Shen, and F.-Q. Huang, “Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2gasochromic films doped with Pd catalyst,” ACS Appl. Mater. Interfaces 3, 4573–4579 (2011).
[CrossRef]

Lusis, A.

A. Lusis, J. Kleperis, and E. Pentjušs, “Model of electrochromic and related phenomena in tungsten oxide thin films,” J. Solid State Electrochem. 7, 106–112 (2003).

Macleod, H. A.

H. A. Macleod, Thin-Film Optical Filters, 3rd ed. (Institute of Physics, 2001).

Macrelli, G.

E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
[CrossRef]

Martinu, L.

B. Baloukas, J.-M. Lamarre, and L. Martinu, “Electrochromic interference filters fabricated from dense and porous tungsten oxide films,” Sol. Energy Mater. Sol. Cells 95, 807–815 (2011).
[CrossRef]

B. Baloukas, J.-M. Lamarre, and L. Martinu, “Active metameric security devices using an electrochromic material,” Appl. Opt. 50, C41–C49 (2011).
[CrossRef]

B. Baloukas and L. Martinu, “Metameric interference security image structures,” Appl. Opt. 47, 1585–1593 (2008).
[CrossRef]

S. Larouche and L. Martinu, “Openfilters: open-source software for the design, optimization, and synthesis of optical filters,” Appl. Opt. 47, C219–C230 (2008).
[CrossRef]

S. Larouche, H. Szymanowski, J. E. Klemberg-Sapieha, L. Martinu, and S. C. Gujrathi, “Microstructure of plasma-deposited SiO2/TiO2 optical films,” J. Vac. Sci. Technol. A 22, 1200–1207 (2004).
[CrossRef]

Masetti, E.

E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
[CrossRef]

Mergel, D.

Messina, F.

F. Messina, M. Cannas, and R. Boscaino, “Generation of defects in amorphous SiO2 assisted by two-step absorption on impurity sites,” J. Phys. Condens. Matter 20, 275210 (2008).
[CrossRef]

Modine, F. A.

G. E. Jellison and F. A. Modine, “Parametrization of the optical functions of amorphous materials in the interband region,” Appl. Phys. Lett. 69, 371–373 (1996).
[CrossRef]

Monk, P. M. S.

P. M. S. Monk, “Charge movement through electrochromic thin-film tungsten trioxide,” Crit. Rev. Solid State Mater. Sci. 24, 193–226 (1999).
[CrossRef]

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University, 2007).

Morita, H.

H. Morita and H. Washida, “Electrochromism of atmospheric evaporated tungsten oxide films (AETOF),” Jpn. J. Appl. Phys. 23, 754–759 (1984).
[CrossRef]

Mortimer, R. J.

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University, 2007).

Moshfegh, A. Z.

N. Naseri, R. Azimirad, O. Akhavan, and A. Z. Moshfegh, “The effect of nanocrystalline tungsten oxide concentration on surface properties of dip-coated hydrophilic WO3-SiO2 thin films,” J. Phys. D 40, 2089–2095 (2007).
[CrossRef]

Naseri, N.

N. Naseri, R. Azimirad, O. Akhavan, and A. Z. Moshfegh, “The effect of nanocrystalline tungsten oxide concentration on surface properties of dip-coated hydrophilic WO3-SiO2 thin films,” J. Phys. D 40, 2089–2095 (2007).
[CrossRef]

Padiyath, R.

R. Padiyath, C. Haak, and L. Gilbert, “Spectrally selective window films,” in 50th Annual Technical Conference of the Society of Vacuum Coaters (Society of Vacuum Coaters, 2007), pp. 669–673.

Papaefthimiou, S.

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “The effect of water on the electrochromic properties of WO3 films prepared by vacuum and chemical methods,” Sol. Energy Mater. Sol. Cells 83, 115–124 (2004).
[CrossRef]

S. Papaefthimiou, G. Leftheriotis, and P. Yianoulis, “Study of WO3 films with textured surfaces for improved electrochromic performance,” Solid State Ion. 139, 135–144 (2001).
[CrossRef]

Park, C.

A. E. Aliev and C. Park, “Development of WO3  thin films using nanoscale silicon particles,” Jpn. J. Appl. Phys. 39, 3572–3578 (2000).
[CrossRef]

Parlett, J.

C. W. Peterson, J. Parlett, and R. S. Crandall, “The physics of electrochromism: an advanced laboratory experiment,” Am. J. Phys. 47, 772–775 (1979).
[CrossRef]

Pentjušs, E.

A. Lusis, J. Kleperis, and E. Pentjušs, “Model of electrochromic and related phenomena in tungsten oxide thin films,” J. Solid State Electrochem. 7, 106–112 (2003).

Peterson, C. W.

C. W. Peterson, J. Parlett, and R. S. Crandall, “The physics of electrochromism: an advanced laboratory experiment,” Am. J. Phys. 47, 772–775 (1979).
[CrossRef]

Phillips, R. W.

Pyun, S.-I.

D.-J. Kim and S.-I. Pyun, “Hydrogen transport through rf-magnetron sputtered amorphous WO3 film with three kinds of hydrogen injection sites,” Solid State Ion. 99, 185–192 (1997).
[CrossRef]

Qiao, Z.

Rosseinsky, D. R.

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University, 2007).

Saini, K. K.

S. A. Agnihotry, K. K. Saini, T. K. Saxena, and S. Chandra, “Electical properties and morphology of obliquely deposited electrochromic WO3 films,” Thin Solid Films 141, 183–192 (1986).
[CrossRef]

Saxena, T. K.

S. A. Agnihotry, K. K. Saini, T. K. Saxena, and S. Chandra, “Electical properties and morphology of obliquely deposited electrochromic WO3 films,” Thin Solid Films 141, 183–192 (1986).
[CrossRef]

Saygin-Hinczewski, D.

D. Saygin-Hinczewski, M. Hinczewski, I. Sorar, F. Z. Tepehan, and G. G. Tepehan, “Modeling the optical properties of WO3 and WO3-SiO2 thin films,” Sol. Energy Mater. Sol. Cells 92, 821–829 (2008).
[CrossRef]

Schirmer, O. F.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Schwartz, M.

M. Schwartz, Smart Materials, 1st ed. (CRC, 2008).

Setlakwe, L.

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

Shen, H.

X. Q. Xu, H. Shen, and X. Y. Xiong, “Gasochromic effect of sol-gel WO3−SiO2 films with evaporated platinum catalyst,” Thin Solid Films 415, 290–295 (2002).
[CrossRef]

Shen, J.

D. Li, G. Wu, G. Gao, J. Shen, and F.-Q. Huang, “Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2gasochromic films doped with Pd catalyst,” ACS Appl. Mater. Interfaces 3, 4573–4579 (2011).
[CrossRef]

Shimizu, I.

I. Shimizu, M. Shizukuishi, and E. Inoue, “Solid-state electrochromic device consisting of amorphous WO3 and Cr2O3,” J. Appl. Phys. 50, 4027–4032 (1979).
[CrossRef]

Shizukuishi, M.

I. Shimizu, M. Shizukuishi, and E. Inoue, “Solid-state electrochromic device consisting of amorphous WO3 and Cr2O3,” J. Appl. Phys. 50, 4027–4032 (1979).
[CrossRef]

Sorar, I.

D. Saygin-Hinczewski, M. Hinczewski, I. Sorar, F. Z. Tepehan, and G. G. Tepehan, “Modeling the optical properties of WO3 and WO3-SiO2 thin films,” Sol. Energy Mater. Sol. Cells 92, 821–829 (2008).
[CrossRef]

Szymanowski, H.

S. Larouche, H. Szymanowski, J. E. Klemberg-Sapieha, L. Martinu, and S. C. Gujrathi, “Microstructure of plasma-deposited SiO2/TiO2 optical films,” J. Vac. Sci. Technol. A 22, 1200–1207 (2004).
[CrossRef]

Tepehan, F. Z.

D. Saygin-Hinczewski, M. Hinczewski, I. Sorar, F. Z. Tepehan, and G. G. Tepehan, “Modeling the optical properties of WO3 and WO3-SiO2 thin films,” Sol. Energy Mater. Sol. Cells 92, 821–829 (2008).
[CrossRef]

Tepehan, G. G.

D. Saygin-Hinczewski, M. Hinczewski, I. Sorar, F. Z. Tepehan, and G. G. Tepehan, “Modeling the optical properties of WO3 and WO3-SiO2 thin films,” Sol. Energy Mater. Sol. Cells 92, 821–829 (2008).
[CrossRef]

Thornton, J. A.

J. A. Thornton, “The microstructure of sputter-deposited coatings,” J. Vac. Sci. Technol. A 4, 3059–3065 (1986).
[CrossRef]

Tracy, C. E.

J.-G. Zhang, C. E. Tracy, D. K. Benson, and S. K. Deb, “The influence of microstructure on the electrochromic properties of LixWO3 thin films: Part I. Ion diffusion and electrochromic properties,” J. Mater. Res. 8, 2649–2656 (1993).
[CrossRef]

Uhlmann, D. R.

M. Denesuk and D. R. Uhlmann, “Site-saturation model for the optical efficiency of tungsten oxide-based devices,” J. Electrochem. Soc. 143, L186–L188 (1996).
[CrossRef]

Wagner, J. B.

T. Jow and J. B. Wagner, “The effect of dispersed alumina particles on the electrical conductivity of cuprous chloride,” J. Electrochem. Soc. 126, 1963–1972 (1979).
[CrossRef]

Waldorf, A.

Wang, J.

J. Wang and J. M. Bell, “The kinetic behaviour of ion injection in WO3 based films produced by sputter and sol-gel deposition: Part II. Diffusion coefficients,” Sol. Energy Mater. Sol. Cells 58, 411–429 (1999).
[CrossRef]

Washida, H.

H. Morita and H. Washida, “Electrochromism of atmospheric evaporated tungsten oxide films (AETOF),” Jpn. J. Appl. Phys. 23, 754–759 (1984).
[CrossRef]

Wittwer, V.

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

Witzke, H.

S. K. Deb and H. Witzke, “The solid state electrochromic phenomenon and its applications to display devices,” in Proceedings of IEEE Conference on International Electron Devices Meeting (IEEE, 1975), pp. 393–397.

Wu, G.

D. Li, G. Wu, G. Gao, J. Shen, and F.-Q. Huang, “Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2gasochromic films doped with Pd catalyst,” ACS Appl. Mater. Interfaces 3, 4573–4579 (2011).
[CrossRef]

Xiong, X. Y.

X. Q. Xu, H. Shen, and X. Y. Xiong, “Gasochromic effect of sol-gel WO3−SiO2 films with evaporated platinum catalyst,” Thin Solid Films 415, 290–295 (2002).
[CrossRef]

Xu, X. Q.

X. Q. Xu, H. Shen, and X. Y. Xiong, “Gasochromic effect of sol-gel WO3−SiO2 films with evaporated platinum catalyst,” Thin Solid Films 415, 290–295 (2002).
[CrossRef]

Yianoulis, P.

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “The effect of water on the electrochromic properties of WO3 films prepared by vacuum and chemical methods,” Sol. Energy Mater. Sol. Cells 83, 115–124 (2004).
[CrossRef]

S. Papaefthimiou, G. Leftheriotis, and P. Yianoulis, “Study of WO3 films with textured surfaces for improved electrochromic performance,” Solid State Ion. 139, 135–144 (2001).
[CrossRef]

Zhang, J.-G.

J.-G. Zhang, C. E. Tracy, D. K. Benson, and S. K. Deb, “The influence of microstructure on the electrochromic properties of LixWO3 thin films: Part I. Ion diffusion and electrochromic properties,” J. Mater. Res. 8, 2649–2656 (1993).
[CrossRef]

ACS Appl. Mater. Interfaces

D. Li, G. Wu, G. Gao, J. Shen, and F.-Q. Huang, “Ultrafast coloring-bleaching performance of nanoporous WO3-SiO2gasochromic films doped with Pd catalyst,” ACS Appl. Mater. Interfaces 3, 4573–4579 (2011).
[CrossRef]

Am. J. Phys.

C. W. Peterson, J. Parlett, and R. S. Crandall, “The physics of electrochromism: an advanced laboratory experiment,” Am. J. Phys. 47, 772–775 (1979).
[CrossRef]

Appl. Opt.

Appl. Phys. Lett.

B. W. Faughnan, R. S. Crandall, and M. A. Lampert, “Model for the bleaching of WO3 electrochromic films by an electric field,” Appl. Phys. Lett. 27, 275–277 (1975).
[CrossRef]

G. E. Jellison and F. A. Modine, “Parametrization of the optical functions of amorphous materials in the interband region,” Appl. Phys. Lett. 69, 371–373 (1996).
[CrossRef]

R. S. Crandall and B. W. Faughnan, “Measurement of the diffusion coefficient of electrons in WO3 films,” Appl. Phys. Lett. 26, 120–121 (1975).
[CrossRef]

Crit. Rev. Solid State Mater. Sci.

P. M. S. Monk, “Charge movement through electrochromic thin-film tungsten trioxide,” Crit. Rev. Solid State Mater. Sci. 24, 193–226 (1999).
[CrossRef]

Electrochim. Acta

C. G. Granqvist, “Progress in electrochromics: tungsten oxide revisited,” Electrochim. Acta 44, 3005–3015 (1999).
[CrossRef]

Indust. Paint Powder

M. Greissel, “The colors they are a-changin’,” Indust. Paint Powder 77, 16–18 (2001).

J. Appl. Phys.

I. Shimizu, M. Shizukuishi, and E. Inoue, “Solid-state electrochromic device consisting of amorphous WO3 and Cr2O3,” J. Appl. Phys. 50, 4027–4032 (1979).
[CrossRef]

J. Electrochem. Soc.

M. Denesuk and D. R. Uhlmann, “Site-saturation model for the optical efficiency of tungsten oxide-based devices,” J. Electrochem. Soc. 143, L186–L188 (1996).
[CrossRef]

O. F. Schirmer, V. Wittwer, G. Baur, and G. Brandt, “Dependence of WO3 electrochromic absorption on crystallinity,” J. Electrochem. Soc. 124, 749–753 (1977).
[CrossRef]

T. Jow and J. B. Wagner, “The effect of dispersed alumina particles on the electrical conductivity of cuprous chloride,” J. Electrochem. Soc. 126, 1963–1972 (1979).
[CrossRef]

J. Mater. Res.

J.-G. Zhang, C. E. Tracy, D. K. Benson, and S. K. Deb, “The influence of microstructure on the electrochromic properties of LixWO3 thin films: Part I. Ion diffusion and electrochromic properties,” J. Mater. Res. 8, 2649–2656 (1993).
[CrossRef]

J. Phys. Condens. Matter

F. Messina, M. Cannas, and R. Boscaino, “Generation of defects in amorphous SiO2 assisted by two-step absorption on impurity sites,” J. Phys. Condens. Matter 20, 275210 (2008).
[CrossRef]

J. Phys. D

N. Naseri, R. Azimirad, O. Akhavan, and A. Z. Moshfegh, “The effect of nanocrystalline tungsten oxide concentration on surface properties of dip-coated hydrophilic WO3-SiO2 thin films,” J. Phys. D 40, 2089–2095 (2007).
[CrossRef]

J. Sol-Gel Sci. Technol.

M. Klisch, “12-tungstosilicic acid (12-TSA) as a tungsten precursor in alcoholic solution for deposition of xWO3(1−x)SiO2 thin films (x<0.7) exhibiting electrochromic coloration ability,” J. Sol-Gel Sci. Technol. 12, 21–33(1998).
[CrossRef]

J. Solid State Electrochem.

A. Lusis, J. Kleperis, and E. Pentjušs, “Model of electrochromic and related phenomena in tungsten oxide thin films,” J. Solid State Electrochem. 7, 106–112 (2003).

J. Vac. Sci. Technol. A

J. A. Thornton, “The microstructure of sputter-deposited coatings,” J. Vac. Sci. Technol. A 4, 3059–3065 (1986).
[CrossRef]

S. Larouche, H. Szymanowski, J. E. Klemberg-Sapieha, L. Martinu, and S. C. Gujrathi, “Microstructure of plasma-deposited SiO2/TiO2 optical films,” J. Vac. Sci. Technol. A 22, 1200–1207 (2004).
[CrossRef]

Jpn. J. Appl. Phys.

A. E. Aliev and C. Park, “Development of WO3  thin films using nanoscale silicon particles,” Jpn. J. Appl. Phys. 39, 3572–3578 (2000).
[CrossRef]

H. Morita and H. Washida, “Electrochromism of atmospheric evaporated tungsten oxide films (AETOF),” Jpn. J. Appl. Phys. 23, 754–759 (1984).
[CrossRef]

Nucl. Instrum. Methods Phys. Res. Sect. B

S. C. Gujrathi and S. Bultena, “Depth profiling of hydrogen using the high efficiency ERD-TOF technique,” Nucl. Instrum. Methods Phys. Res. Sect. B 64, 789–795 (1992).
[CrossRef]

Proc. SPIE

L. Setlakwe and L. A. DiNunzio, “Comparative analysis of public opinion research in the U.S. and Canada,” Proc. SPIE 5310, 13–24 (2004).
[CrossRef]

Sol. Energy Mater. Sol. Cells

B. Baloukas, J.-M. Lamarre, and L. Martinu, “Electrochromic interference filters fabricated from dense and porous tungsten oxide films,” Sol. Energy Mater. Sol. Cells 95, 807–815 (2011).
[CrossRef]

D. Saygin-Hinczewski, M. Hinczewski, I. Sorar, F. Z. Tepehan, and G. G. Tepehan, “Modeling the optical properties of WO3 and WO3-SiO2 thin films,” Sol. Energy Mater. Sol. Cells 92, 821–829 (2008).
[CrossRef]

E. Masetti, M. L. Grilli, G. Dautzenberg, G. Macrelli, and M. Adamik, “Analysis of the influence of the gas pressure during the deposition of electrochromic WO3 films by reactive r.f. sputtering of W and WO3 target,” Sol. Energy Mater. Sol. Cells 56, 259–269 (1999).
[CrossRef]

G. Leftheriotis, S. Papaefthimiou, and P. Yianoulis, “The effect of water on the electrochromic properties of WO3 films prepared by vacuum and chemical methods,” Sol. Energy Mater. Sol. Cells 83, 115–124 (2004).
[CrossRef]

J. Wang and J. M. Bell, “The kinetic behaviour of ion injection in WO3 based films produced by sputter and sol-gel deposition: Part II. Diffusion coefficients,” Sol. Energy Mater. Sol. Cells 58, 411–429 (1999).
[CrossRef]

S. K. Deb, “Reminiscences on the discovery of electrochromic phenomena in transition metal oxides,” Sol. Energy Mater. Sol. Cells 39, 191–201 (1995).
[CrossRef]

Solid State Ion.

D.-J. Kim and S.-I. Pyun, “Hydrogen transport through rf-magnetron sputtered amorphous WO3 film with three kinds of hydrogen injection sites,” Solid State Ion. 99, 185–192 (1997).
[CrossRef]

S. Papaefthimiou, G. Leftheriotis, and P. Yianoulis, “Study of WO3 films with textured surfaces for improved electrochromic performance,” Solid State Ion. 139, 135–144 (2001).
[CrossRef]

Thin Solid Films

S. A. Agnihotry, K. K. Saini, T. K. Saxena, and S. Chandra, “Electical properties and morphology of obliquely deposited electrochromic WO3 films,” Thin Solid Films 141, 183–192 (1986).
[CrossRef]

D. E. Aspnes, “Optical properties of thin films,” Thin Solid Films 89, 249–262 (1982).
[CrossRef]

X. Q. Xu, H. Shen, and X. Y. Xiong, “Gasochromic effect of sol-gel WO3−SiO2 films with evaporated platinum catalyst,” Thin Solid Films 415, 290–295 (2002).
[CrossRef]

Other

R. van Renesse, ed., Optical Document Security, 2nd ed.(Artech House, 1998).

H. A. Macleod, Thin-Film Optical Filters, 3rd ed. (Institute of Physics, 2001).

C. G. Granqvist, Handbook of Inorganic Electrochromic Materials (Elsevier, 1995).

R. Padiyath, C. Haak, and L. Gilbert, “Spectrally selective window films,” in 50th Annual Technical Conference of the Society of Vacuum Coaters (Society of Vacuum Coaters, 2007), pp. 669–673.

M. Schwartz, Smart Materials, 1st ed. (CRC, 2008).

B. D. Cullity, Elements or X-Ray Diffraction, 2nd ed.(Addisson-Wesley, 1979).

J. Tauc, ed., Amorphous and Liquid Semiconductors (Plenum, 1974).

P. M. S. Monk, R. J. Mortimer, and D. R. Rosseinsky, Electrochromism and Electrochromic Devices (Cambridge University, 2007).

S. K. Deb and H. Witzke, “The solid state electrochromic phenomenon and its applications to display devices,” in Proceedings of IEEE Conference on International Electron Devices Meeting (IEEE, 1975), pp. 393–397.

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Figures (10)

Fig. 1.
Fig. 1.

Refractive index and extinction coefficient as a function of energy for pure WO 3 and mixed WO 3 / SiO 2 films deposited at 10 mTorr. The index of refraction at 550 nm is also shown (2.26 eV). Note that the absorption is negligible in the visible range of the spectrum.

Fig. 2.
Fig. 2.

Refractive index at 550 nm as a function of the relative WO 3 concentration estimated from the Bruggeman effective medium approximation for films deposited at 10 mTorr. The [ W ] / [ Si ] + [ W ] values obtained from the RBS measurements are also plotted with their corresponding refractive index. The density of the films and their hydrogen content are also shown.

Fig. 3.
Fig. 3.

Atomic force microscopy images of pure WO 3 and WO 3 / SiO 2 mixtures (identified in the upper left corner). The RMS roughness and surface area difference (SAD) are also indicated under each image. The maximum amplitude difference between the minimum and maximum values is shown in the bottom right corner; we indicate the scaling factor, which was required in order to maintain the same color scale, in the upper right corner for (a) and (b).

Fig. 4.
Fig. 4.

Eleventh cyclic voltammogram for films deposited at 10 mTorr with various WO 3 concentrations. The minimum and maximum current values of each cycle are also indicated on the left side of the voltammograms.

Fig. 5.
Fig. 5.

Normalized inserted charge evolution as a function of time calculated from the 11th voltammogram presented in the previous figure. The charge was normalized using the maximum inserted charge of each voltammogram. The ratio of extracted versus inserted charge is also indicated on the right side of the figure (dashed line).

Fig. 6.
Fig. 6.

(a) Ionic diffusion coefficient and (b) CE ( CE 550 nm ) for the eleventh cycle of films deposited at 10 and 20 mTorr. The light blue area indicates the region for which the samples indicated no EC activity.

Fig. 7.
Fig. 7.

Eleventh cyclic voltammograms of two tandem film configurations (A and B) and the individual films they are based on. The transmission variation during this same cycle is also shown in the lower right corner. Note that the transmission reference was made in the bleached state.

Fig. 8.
Fig. 8.

Evolution of the coloration front as a function of time for pure WO 3 and two composite films all deposited at 10 mTorr. Note that the initial radius does not start at zero since the image capture was not synchronized with the indium wire contact time and that the indium wire’s finite size limits initial measurements.

Fig. 9.
Fig. 9.

Transmission spectrum of a fabricated 11 layer interference filter on B270 glass based on pure WO 3 as the high index of refraction and a mixed ( SiO 2 ) 0.83 ( WO 3 ) 0.17 film as the low index of refraction material. Pictures of the filter at (a) normal incidence and at (b) a 50° angle show its blue to purple color shift in transmission.

Fig. 10.
Fig. 10.

Transmission variation as a function of time during 100 cyclic voltammetry cycles for the 11 layer interference filter presented in Fig. 9. The wavelengths were chosen outside the reflection band of the filter and closer to the maximum absorption band of amorphous WO 3 around 1 µm. Note that the transmission reference was made in the bleached state.

Tables (2)

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Table 1. Deposition Conditions and Thickness of the WO 3 and WO 3 / SiO 2 Mixturesa

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Table 2. Ionic and Electron Diffusion Coefficients for a Pure WO 3 Film and Two Composite Films All Deposited at 10 mTorra

Equations (5)

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f SiO 2 n SiO 2 2 n WO 3 / SiO 2 2 n SiO 2 2 + 2 n WO 3 / SiO 2 2 + f WO 3 n WO 3 2 n WO 3 / SiO 2 2 n WO 3 2 + 2 n WO 3 / SiO 2 2 = 0 ,
i p = 0.4463 n F A c n F v D i R T ,
CE = ln [ T b / T c ] [ Q / A ] ,
A : ITO | 72 nm ( WO 3 ) 0.17 ( SiO 2 ) 0.83 | 101 nm WO 3 , and B : ITO | 92 nm WO 3 | 86 nm ( WO 3 ) 0.17 ( SiO 2 ) 0.83 ,
R 2 2 D e t = 1 ,

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