Electrochromic device
According to one embodiment, provided is an electrochromic device including an electrochromic layer, which contains a tungsten oxide material. The tungsten oxide material includes potassium-containing tungsten oxide particles having an average particle size of 100 nm or less. The potassium-containing tungsten oxide particles contain potassium within a range of 1 mol % to 50 mol %, and include a central section and a peripheral section adjacent to the central section. A periodicity of a crystal varies between the central section and the peripheral section.
1. An electrochromic device comprising an electrochromic layer, the electrochromic layer containing a tungsten oxide material, the tungsten oxide material comprising potassium-containing tungsten oxide particles, the potassium-containing tungsten oxide particles having an average particle size of 100 nm or less, containing potassium within a range of 1 mol % to 50 mol %, and including a central section and a peripheral section adjacent to the central section, a periodicity of a crystal varying between the central section and the peripheral section,
wherein the potassium-containing tungsten oxide particles have a crystal structure in which plural phases intersecting with a direction from inside toward a surface of the particles and being parallel to each other are sequentially arranged in the direction, and wherein an interatomic distance I c between the plural phases adjacent to each other in the central section is different from an interatomic distance I p between the plural phases adjacent to each other in the peripheral section.
2. The electrochromic device according to claim 1 , wherein an abundance of the potassium in the potassium-containing tungsten oxide particles is greater in the peripheral section than that in the central section.
3. The electrochromic device according to claim 2 , wherein the peripheral section has a maximum width of 1.5 nm to 5 nm.
4. The electrochromic device according to claim 2 , wherein a content of the potassium-containing tungsten oxide particles in the electrochromic layer is 90% to 99.5% in terms of an area ratio.
5. The electrochromic device according to claim 2 , wherein the potassium-containing tungsten oxide particles account for 80% by mass to 100% by mass of the tungsten oxide material in the electrochromic layer.
6. The electrochromic device according to claim 2 , wherein a distance between the potassium-containing tungsten oxide particles adjacent to each other in the electrochromic layer is smaller than the average particle size of the potassium-containing tungsten oxide particles.
7. The electrochromic device according to claim 1 , wherein a ratio K XPS /K ICP of a content K XPS of the potassium in the potassium-containing tungsten oxide particles according to X-ray photoelectron spectroscopy to a content K ICP of the potassium in the potassium-containing tungsten oxide particles according to an inductively coupled plasma emission spectrometric analysis method is 1.05 or more.
8. The electrochromic device according to claim 7 , wherein the peripheral section has a maximum width of 1.5 nm to 5 nm.
9. The electrochromic device according to claim 7 , wherein a content of the potassium-containing tungsten oxide particles in the electrochromic layer is 90% to 99.5% in terms of an area ratio.
10. The electrochromic device according to claim 7 , wherein the potassium-containing tungsten oxide particles account for 80% by mass to 100% by mass of the tungsten oxide material in the electrochromic layer.
11. The electrochromic device according to claim 7 , wherein a distance between the potassium-containing tungsten oxide particles adjacent to each other in the electrochromic layer is smaller than the average particle size of the potassium-containing tungsten oxide particles.
12. The electrochromic device according to claim 1 , wherein the peripheral section has a maximum width of 1.5 nm to 5 nm.
13. The electrochromic device according to claim 12 , wherein a content of the potassium-containing tungsten oxide particles in the electrochromic layer is 90% to 99.5% in terms of an area ratio.
14. The electrochromic device according to claim 12 , wherein the potassium-containing tungsten oxide particles account for 80% by mass to 100% by mass of the tungsten oxide material in the electrochromic layer.
15. The electrochromic device according to claim 12 , wherein a distance between the potassium-containing tungsten oxide particles adjacent to each other in the electrochromic layer is smaller than the average particle size of the potassium-containing tungsten oxide particles.
16. The electrochromic device according to claim 1 , wherein a content of the potassium-containing tungsten oxide particles in the electrochromic layer is 90% to 99.5% in terms of an area ratio.
17. The electrochromic device according to claim 1 , wherein the potassium-containing tungsten oxide particles account for 80% by mass to 100% by mass of the tungsten oxide material in the electrochromic layer.
18. The electrochromic device according to claim 1 , wherein a distance between the potassium-containing tungsten oxide particles adjacent to each other in the electrochromic layer is smaller than the average particle size of the potassium-containing tungsten oxide particles.