Fabrication And Properties Of PB Electrochromic Devices In Preparation

Electrochromic materials are deemed to be one of the most promising smart materials.Electrochromic is the phenomenon that the optical properties?reflectivity,transmittance,absorbance,etc.?of the materials have stable and reversible color change under the action of applied electric field,which is reflected in the reversible change of color and transparency.Electrochromic materials can be served at windows to reduce the thermal load of air-conditioning system,and can be used as a confidential coating to achieve the goal of energy saving.Prussian blue is the coexistence of Fe²⁺and Fe³⁺,and Prussian white?PW?is produced when Fe³⁺is reduced.This is the most common redox process of Prussian blue?PB?.However,when the Fe²⁺portion of Prussian blue is oxidized to Fe³⁺,a green substance is generated at this time,called Prussian green?PG?.Recently,the research of prussian blue as electrochromic materials has been more,and the research on the direct growth of hydrothermal method and the research of Prussian blue complementary devices are less reported.Therefore,we have researched the work about the Prussian blue thin film by the direct growth by hydrothermal method,and the complementary electrochromic devices and research its electrochromic properties of Prussian blue.The influence of temperature on the structure and morphology of the Prussian blue films were studied.The effects of the addition of ascorbic acid on the properties of Prussian blue were also studied.The electrochromic properties of the component were measured.Then using aluminum as an spright metal,it is prone to ridding the electron into Al³⁺.The reduced Prussian white is easily oxidized by the oxygen in air to form Prussian blue self-powered electrochromic device and to study its performance.Inaddition,Prussiangreenfilmsweregrowndirectlyonto hydrofluorocarbon-doped tin oxide?FTO?glass and assembled into electrochromic devices,their synthesis mechanism was investigated and the electric power assembled by them was tested induced discoloration device performance.The primary results are this:?1?PB films grown by direct hydrothermal growth at 150 ^oC by the addition of ascorbic acid have a thickness of about 300 nm,and whose surfaces are filled with a lot of cracks.The device assembled with PB film has faster color rendering and fading response time?2.8 s coloring time,1.3 s fading time?and higher light modulation amplitude?58.0%at 700 nm?and charge density(52.4 cm²·C^-1)with good electrochromic properties.?2?The use of aluminum as an active metal easily releases electrons into Al³⁺.Reduced Prussian White is easily oxidized by oxygen in the air.Ascorbic acid and potassium ferricyanide aqueous solutions are used as precursors at 120 ^oC.Prussian blue film was developed straintly on FTO by hydro-thermal method,and Prussian blue self-powered electrochromic device was made by thin film.The device's transmission rate reached 51%at650 nm,and the coloring and fading times were 2.0 s and 0.6 s,respectively.The discharge capacity of the device is 51.9 mA?h?g^-1.?3?Prussian green?PG?films were grown directly on FTO by hydrothermal method and assembled into electrochromic devices with a thickness of about 500 nm.PG films were assembled into devices.The coloring and fading response time is 12.5 s and 3.5 s,respectly.The light modulation amplitude is 40.0%at 730 nm.The charge density of PG devices is 52.4cm²·C^-11 with good electrochromic properties and good cyclical stability.The discharge capacity reaches 60.4 mA?h?g^-1,which is higher than PB.