Thin film lithium tungsten oxides for electrochromic applications and methods of making the same
View Patent ↗An electrochromic multi-layer stack is provided. The electrochromic multi-layer stack includes a thin film that includes lithium tungsten oxide with lithium included in the fully bleached state. The electrochromic multi-layer stack also includes an electrically conductive layer, and an outer substrate. An electrochromic device is also provided.
1. An electrochromic multi-layer stack comprising:
a thin film comprising lithium tungsten oxide with the formula Li x WO 3+y wherein x is greater than 0 and less than or equal to 1, and y is greater than 0 and less than or equal to 0.5 in the fully bleached state;
an electrically conductive layer; and
an outer substrate,
wherein the electrochromic multi-layer stack has a Tvis greater than 80% in the fully bleached state.
2. The electrochromic multi-layer stack of claim 1 , further comprising:
L* from 80 to 100 in the fully bleached state;
a* from −10 to 10 in the fully bleached state; and
b* from −5 to 5 in the fully bleached state.
3. The electrochromic multi-layer stack of claim 1 , further comprising:
b* from −5 to 5 in the fully bleached state.
4. The electrochromic multi-layer stack of claim 1 , further comprising:
a darkened state Tvis less than 15%.
5. The electrochromic multi-layer stack of claim 1 , further comprising:
a coloration efficiency greater than 10 cm 2 /C.
6. The electrochromic multi-layer stack of claim 1 , further comprising:
a switching rate from −1 to 0.
7. The electrochromic multi-layer stack of claim 1 , wherein the lithium tungsten oxide is partially crystalline.
8. The electrochromic multi-layer stack of claim 1 , wherein the lithium tungsten oxide has a perovskite crystal structure.
9. The electrochromic multi-layer stack of claim 8 , wherein the lithium tungsten oxide has a perovskite crystal structure with a space group P4/nmm.
10. The electrochromic multi-layer stack of claim 8 , wherein the lithium tungsten oxide has a perovskite crystal structure with a space group P4/nmm, and lattice parameters of a=b=from approximately 5.2 angstroms to approximately 5.3 angstroms, and c=from approximately 3.8 angstroms to approximately 3.9 angstroms.
11. The electrochromic multi-layer stack of claim 8 , wherein the lithium tungsten oxide has Raman peaks at approximately 805 cm −1 , at approximately 950 cm −1 , at approximately 680-715 cm −1 , and at approximately 270 cm −1 .