Synthesis And Electrochromic Properties Of Prussian Blue Analogues Nanostructures

Nowadays,the problem of environmental pollution and energy shortage is becoming more and more serious around the world which seriously affects the sustainable development of society.Reducing environmental pollution and energy consumption has becoming the primary task of today's society.Energy saving and environmental protection materials have come into being.As a kind of energy saving and environmental protection material,electrochromic materials have been successfully applied in the "intelligent window",“anti-glare rearview mirror”and“display”.In short,its application prospect and value are boundless.Prussian blue analogue has been widely studied in recent years because of its wide range of sources,good circulation stability and rich color change.In this paper,different kinds of Prussian blue analogues were prepared by coprecipitation method.Different kinds of Prussian blue analogues films were prepared by spin coating method.This method was easy to operate and low in cost.Tungsten oxide films with different morphologies were prepared by solvothermal method.In this experiment,the nickel ferricyanide film with different organic polymers,cobalt ferricyanide film with PEDOT:PSS,tungsten oxide films with net-like and flower-like structure were prepared.XRD and SEM were used to analyze and characterize the Prussian blue analogues.The electrochromic devices based nickel ferricyanide film,cobalt ferricyanide film,tungsten oxide film and complementary device were assembled and the electrochromic properties of each device were tested and compared.(1)The nickel ferrocyanide powder with the size of 50-60 nm was prepared by coprecipitation of potassium ferricyanide and nickel acetatein.In order to get a more uniform and firm film,we added PEDOT:PSS or PVP into the suspension and studied the influence of different polymers on the film uniformity and electrochromic properties.The films were assembled into electrochromic(EC)device and the electrochromic performance including transmittance spectra and response time were tested.The results showed that the prepared nickel hexacyanoferrate powder reached nanometer level.The modulation amplitudethe of devices based nickel ferricyanide with PEDOT:PSS and nickel ferricyanide with PVP both reached largest at 400nm(15 % vs 12 % respectively).Besides,the colored time and bleached time of devicebased nickel ferricyanide with PEDOT:PSS was 4 s and 21 s and nickel ferricyanide with PVP was 51 s and 36 s.(2)The cobalt ferrocyanide powder was synthesized by coprecipitation of potassium ferricyanide and cobalt acetate.It was similar to nickel ferrocyanide powder.The particle size was about 50-60 nm.The cobalt ferricyanide film with PEDOT:PSS was doped on ITO transparent conductive glass by spin coating and the films were assembled into a device.The transmittance spectrum of device based cobalt ferricyanide with PEODOT:PSS films were found to reach a maximum of 10%at the wavelength of 470 nm.The response time of device based cobalt ferricyanide with PEODOT:PSS films to be green and red was 4.3 s and 3 s respectively,and the change time was very short.(3)The tungsten oxide films with nano net-like stucture and nano flower-like structure were prepared by changing the solvent during the solvothermal method.The tungsten oxide thin film with a thickness of about 400 nm was prepared by ethanol as a solvent.When the tetrahydrofuran and ethanol were used as solvent,the thickness of the flower-like structure of tungsten oxide thin film was about 754 nm.The nickel ferrocyanide with PEDOT:PSS films on FTO conductive glass with a thickness of about 3.19 ?m and a particle size of about 50-60 nm were prepared by spin coating.The tungsten oxide thin films were assembled into tungsten oxide electrochromic devices and complementary devices respectively.The modulation amplitudethe of the tungsten oxide electrochromic devices and complementary devices both reached largest at 750 nm(40 % vs 35 %).Besides,the colored time and bleached time of device based tungsten oxide thin films was 87.9 s and 20.5 s.While the colored time and bleached time of complementary deviceswas 65 s and 22 s.