All Solid State Electrochromic Devices With Ultra Small Working Area And Tunable Color

Electrochromic(EC)technology for displays and smart windows has attracted much attention in the past decades.A lot of EC materials and devices were discovered and designed.EC display is highly competitive among the current display technologies,such as liquid-crystal(LCD)and organic light emitting(OLED)panels,due to advantages such as low driving voltage,energy saving,long lifetime,simple device structure,easily to be made into large-area and flexible devices and memory ability.Many oxides of transition metals such as tungsten,nickel,vanadium,titanium,and molybdenum show EC properties.Comparing with organic EC materials,they have advantages such as much higher thermal stability and radiation resistance,thus having high potential in large area and outdoor display.Among inorganic EC materials,WO3 is a key material of choice because of its multiple valence states,high coloration efficiency,and good stability.WO3-based electrochromic displays(ECDs)have attracted a lot of attentions as a complimentary technology to the main-stream such as LCD and OLED,but very limited work has been reported on the resolution and color control of ECDs despite it being key parameters of any display technology.Thus we researched resolution and color control of ECDs during my graduate study.In this work,WO3 based ECDs with pixel sizes down to 1.9 ?m and 87 nm were fabricated by UV lithography and electron-beam lithography,respectively.It demonstrating the potential of achieving ultra-high resolution ECDs.The devices were entirely solid state and have been fabricated on both glass and flexible substrates.We also guaranteed high electrochromic performance with a large optical contrast up to 60.6%and coloration efficiency up to 63.7 cm2/C.Moreover,solid-state EC devices based on V-doped WO3 were fabricated on a flexible PET and glass substrate by RF co-sputtering method at room temperature without any thermal treatment.Our results indicate that via adjusting V-doping concentration and processing parameters,EC device with various colors(blue,brown,gray,etc.),and good EC property can be realized.