Preparation And Properties Study Of Conducting Polymer-inorganic/Organic Small Molecule Nanocomposites Electrochromic Materials

Electrochromic materials?EC?as a new type of energy efficient materials have attracted much attention due to their unique display properties,and have great potential applications in smart window,display,electronic paper and military camouflage.Conducting polymer electrochromic?PEC?materials are considered to be the next generation of electrochromic materials,which can be attributed to their various kinds,wide variety of sources,easy structure modification,good processing performance and fast switchting time.In recent years,a lot of reports have been focused on the composite of conducting polymer and various nanostructures to further improve the photoelectric properties of the composite materials,so nanocomposite has become one of the hotspots in the field of electrochromism.In order to improve the electrochromic properties of conducting polymers,the influence of the nanostructures of these materials on the properties of conducting polymers was studied by the way of composite of conducting polymers with inorganic semiconductor/organic small molecular materials?titanium dioxide?Ti O₂?nanorod arrays/copper phthalocyanine?Cu Pc?nanowires?with different morphologies.In the first part of this paper,Cu Pc-polyaniline?PANI?nanocomposites were prepared by electrodeposition and electrochemical polymerization.The electrochromic properties of PANI film and Cu Pc-PANI composite film were studied,the results show that the optical contrast of PANI film at 730 nm is 56%,the discoloring time is 2.9 s,and the coloring time is 0.9 s;the optical contrast of Cu Pc-PANI composite film at 730 nm is 58%,the discoloring time is 1.96 s,and the coloring time is 1.02 s.After 500 cycles,the electrochemical activity of PANI film decreased by 51.98%,while that of Cu Pc-PANI composite film decreased by 31.29%.The results show that the introduction of Cu Pc nanowires improves the electrochemical stability and switching time of PANI films.At the same time,the charge-discharge curves of Cu Pc-PANI composite film at different current densities were measured by electrochemical workstation.The results show that the composite film has a pseudocapacitance property and its areal capacitance is 5.4 m F?cm^-2 at the current density of 0.1 m A?cm^-2.This should be attributed to the fact that Cu Pc in the composite film would be an excellent optoelectronic semiconductor material.The introduction of Cu Pc nanowires in the composite film increases the contact interface between conducting polymer and electrolyte solution,which is conducive to ion diffusion and charge transfer,thus improving the overall performance of the material.In the second part of this paper,Ti O₂ nanorod arrays were prepared on transparent conducting glass FTO by hydrothermal method,and then the PTPA-HATN film and Ti O₂-PTPA-HATN core/shell composite film were prepared by in-situ electrochemical polymerization of tri?4-diphenyl?-hexaazanaphthalene?TPA-HATN?.The influence of Ti O₂ on the electrochromic properties of PTPA-HATN was studied.The results show that the optical contrast of PTPA-HATN film at 783 nm is 62%,the discoloring time is 8.84 s and the coloring time is 10.95 s,while the optical contrast of Ti O₂-PTPA-HATN composite film at 783 nm is 68%,the discoloring time is 2.83 s and the coloring time is 3.16 s.After 400 cycles?with a residence time of 6 s?,the optical contrast of the PTPA-HATN film decreased to the initial 1%,while the optical contrast of the Ti O₂-PTPA-HATN composite film decreased to the initial 48%.It is confirmed that the introduction of Ti O₂ nanorods array can obviously improve the electrochromic properties of PTPA-HATN.In addition,the possible mechanism of ion diffusion to improve the properties of the composite films is proposed.The core/shell structure shortens the ion diffusion distance and increases the contact site,thus improving the electrochromic properties of the polymer.In the third part of this paper,we used hydrothermal method and electrochemical cyclic voltammetry to electropolymerize the reported tris[4-?thiophen-2-yl?-phenyl]amine?TPAT?on Ti O₂ nanorods,and prepared Ti O₂-PTPAT core/shell composite film.The optical contrast of the composite film of 43%at 600 nm and 79%at 1100 nm,the discoloring time is 3.35 s,the coloring time is 4.43 s.Compared with the PTPAT film,the optical contrast of the composite film at 600 nm and 1100 nm changed from 28%to 43%,60%to 79%,and switching time of the composite film are enhanced 0.51 s and 1.09 s,respectively.It can be seen that Ti O₂ nanorods improve the properties of PTPAT films,because the ordered nano array structure improves the specific surface areas and ion diffusion speed of the films.At the same time,the PTPAT₁ film and Ti O₂-PTPAT₁ composite film were prepared by CV polymerization as electrochromic layer respectively.The PEDOT:PSS film prepared by spin coating as ion storage layer.The electrochromic devices ECD₀ and ECD₁ were obtained by assembling the two kinds of films respectively.The spectroelectrochemical data were tested,and the results showed that the device ECD₁ had better electrochromic performance.The switching time of the device ECD₁ was shortened by 1.81 s at 433nm,and the optical contrast of the device ECD₁ was changed from 48%to 56%at 433nm,28%to 33%at 1100 nm,the discoloring time is shortened by 0.58 s,and the coloring time is shortened by 2.69 s.It can be seen that the prototype device based on the composite film has better optical contrast and switching time than the non-composite device.The introduction of ordered Ti O₂ nano array structure is conducive to ion doping and de-doping in the device,which can improve the performance.