Chromogenically tunable photonic crystals
First Claim
1. A method of fabrication of an electrochromically tunable photonic device, the method comprising the steps of:
- (a) providing a first transparent conductor coated substrate having a film side comprising the transparent conductor coating;
(b) providing an electrochromic transition metal oxide inverse opal structure;
(c) providing electrolyte solution as a source of metal ions;
(d) providing a second transparent conductor coated substrate having a film side comprising the transparent conductor coating; and
(e) sandwiching the electrochromic transition metal oxide inverse opal structure and the electrolyte solution between the film side of said first transparent conductor coated substrate and the film side of the second transparent conductor coated substrate.
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Abstract
Tunable photonic crystals offer an interesting possibility to adjust the photonic band gap (PBG) as per requirement. Various methods of achieving this have been tried that include polarization of liquid crystals, thermal effects and more. Chromogenic devices provided in accordance with the present invention include combinations and subcombinations of electrochromic, photochromic, thermochromic devices featuring TMO based inverse opals having tunable photonic band gaps (PBG) for certain frequencies. Electrochromic (EC) materials in which a reversible optical property change can be induced with the application of a small electric field offer a novel possibility to tune the PBG in a controlled and reversible way. The reversible chemical change and the ensuing change of optical constants in these periodically arranged EC materials make the PBG tunability possible. In a recent work we have demonstrated for the first time the PBG tunability of EC materials deposited in the form of periodic inverse opals. This earlier work was carried out with the well known Tungsten Trioxide (WO3) EC thin films into which lithium intercalation was done by a dry lithiation method. In the present work we report on the fabrication of a simple tunable photonic crystal device based on electrochemical insertion/extraction of lithium based on WO3 inverse opals. In alternative embodiments, any suitable transparent conductor can be utilised instead of Indium Tin Oxide (ITO); any suitable electrochromic transition metal oxide, such as for example Molybdenum Oxide (MoO3), Vanadium Pentoxide (V2O5), Titanium Oxide (TiO2), Chromium Oxide (Cr2O3), or Cerium Oxide (CeO2) can be utilised instead of Tungsten Oxide (WO3); and any suitable electrolyte solution can be utilised instead of LiClO4 in Polypropylene Carbonate (LiClO4/PC) solution.
15 Citations
52 Claims
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1. A method of fabrication of an electrochromically tunable photonic device, the method comprising the steps of:
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(a) providing a first transparent conductor coated substrate having a film side comprising the transparent conductor coating;
(b) providing an electrochromic transition metal oxide inverse opal structure;
(c) providing electrolyte solution as a source of metal ions;
(d) providing a second transparent conductor coated substrate having a film side comprising the transparent conductor coating; and
(e) sandwiching the electrochromic transition metal oxide inverse opal structure and the electrolyte solution between the film side of said first transparent conductor coated substrate and the film side of the second transparent conductor coated substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An electrochromically tunable photonic crystal device comprising:
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(a) a first Indium Tin Oxide (ITO) substrate having a film side comprising the ITO coating, the film side capable of acting as a first electrode;
(b) an WO3 inverse opal layer structure provided in contact with the film side of the first ITO substrate;
(c) a LiClO4 in Polypropylene Carbonate (LiClO4/PC) solution provided in contact with the WO3 inverse opal structure; and
(d) a second ITO substrate having a film side comprising the ITO coating, the film side capable of acting as a second electrode in contact with the LiClO4/PC solution;
whereby the application of an electric field between the first and second electrodes would result in reversible coloration by reversible formation of tungsten bronze (LixWO3) as follows;
WO3 (transparent)+xe−
+xLi+⇄
LixWO3 (blue). - View Dependent Claims (27, 28, 29, 30, 31, 32, 33)
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34. An electrochromically tunable photonic device comprising:
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(a) a first transparent conductor coated substrate having a film side comprising the transparent conductor coating, the film side capable of acting as a first electrode;
(b) an electrochromic transition metal oxide inverse opal layer structure provided in contact with the film side of the first transparent conductor coated substrate;
(c) an electrolyte solution as a source of metal ions provided in contact with the electrochromic transition metal oxide inverse opal structure; and
(d) a second transference substrate having a film side comprising the transparent conductor coating, the film side capable of acting as a second electrode in contact with the electrolyte solution;
whereby the application of an electric field between the first and second electrodes would result in reversible coloration by reversible reaction as follows;
[electrochromic transition metal oxide] (bleached/colored)+xe−
+x[metal ion]+⇄
[metal ion]x[electrochromic transition metal oxide] (colored/bleached). - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A chromogenically tunable photonic crystal device comprising:
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(a) a substrate;
(b) a transition metal oxide inverse opal layer structure provided in contact with the substrate;
whereby the application of an external stimuli results in reversible coloration of the transition metal oxide inverse opal layer structure. - View Dependent Claims (50, 51, 52)
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Specification