Electrochromic devices

An electrochromic device comprising:

• (a) an electrochromic layer comprising an electrochromic material, and
• (b) a counter electrode layer comprising a counter electrode material comprising a material selected from the group consisting of:
• a chromium oxide-based material, a manganese oxide-based material, a Prussian blue-based material, and combinations thereof, and
• (c) an interfacial region between the electrochromic layer and the counter electrode layer, wherein the interfacial region is formed, at least partially, from an oxygen-rich portion of the electrochromic layer and/or from an oxygen-rich portion of the counter electrode layer,
• wherein the device does not contain a compositionally homogeneous layer of electrically insulating, ion conducting material between the electrochromic layer and the counter electrode layer.

An electrochromic device comprising:

• (a) an electrochromic layer comprising an electrochromic material, and
• (b) a counter electrode layer comprising a counter electrode material comprising a vanadium oxide-based material, and
• (c) an interfacial region between the electrochromic layer and the counter electrode layer, wherein the interfacial region is formed, at least partially, from an oxygen-rich portion of the electrochromic layer and/or from an oxygen-rich portion of the counter electrode layer,
• wherein the device does not contain a compositionally homogeneous layer of electrically insulating, ion conducting material between the electrochromic layer and the counter electrode layer.

A method of fabricating an electrochromic device, the method comprising:

• forming an electrochromic layer comprising an electrochromic material;
• forming a counter electrode layer in contact with the electrochromic layer without first providing an ion conducting electronically insulating layer between the electrochromic layer and the counter electrode layer, wherein the counter electrode layer comprises a counter electrode material comprising a material selected from the group consisting of:
• a nickel oxide-based material, a chromium oxide-based material, a manganese oxide-based material, a Prussian blue-based material, a vanadium oxide-based material, a cerium titanium oxide-based material, a cerium zirconium oxide-based material, a nickel oxide-based material, and combinations thereof;
• and
• forming an interfacial region, between the electrochromic layer and the counter electrode layer, using components of one or both the electrochromic layer and counter electrode layer, wherein said interfacial region is substantially ion conducting and substantially electronically insulating.