Preparation Of Carbon Quantum Dot Hybrids And Their Electrochromic Properties

Electrochromism refers to the phenomenon that electroactive materials undergo a reversible and lasting change in color under a certain electric field.The key to affect the performance of electrochromic devices is electrochromic electrode materials,so finding electrochromic materials with high contrast,short response time,and high cycle stability has become one of the focuses of current research on electrochromic devices.The goal of this subject is to design and prepare composite electrochromic materials and carry out research work.It is expected that the special properties of carbon quantum dots will be used to further improve the performance of organic and inorganic electrochromic materials,and obtain good electrochemical properties and electrical Photochromic composites.In this paper,the good water solubility and dispersibility are used to introduce them into electrochromic systems.Through in-situ recombination and covalent bonding methods,carbon quantum dot-doped electrochromic composites are obtained.The intermolecular interface interaction enhances the material's electrochromic properties.The carbon quantum dots prepared by hydrothermal were polymerized in situ with polyaniline and hydrothermally compounded with Prussian blue to prepare a high-contrast,fast-response composite material film,and an electrochromic device was assembled.Transmission electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,Raman spectroscopy,and Fourier transform infrared spectroscopy were used to characterize the structure and morphology of the materials,and the electrochemical properties of the composites and the electro-optical Discoloration performance.The end result is as follows:(1)First,the "bottom-up" method was used to prepare the carbon quantum dots.The carbon properties of the prepared carbon quantum dots were tested by ultraviolet spectroscopy by changing the ratio of amino and carboxyl groups and the reaction time The results showed that the increase of the carbon quantum dots' fluorescence performance will also be better.With the increase of the reaction time,the position of the absorption peak of the carbon quantum dot will be red-shifted,and the degree of carbonization will be higher,indicating that its conductivity is also better.(2)Composite carbon quantum dots with organic electrochromic materials,select the most widely used and most studied polyaniline,hybridize carbon quantum dots with polyaniline by in-situ polymerization,and discover three types of C,N,and O through XPS The positions of the peaks corresponding to the elements all move in the direction of large binding energy,which also illustrates the successful recombination of carbon quantum dots and polyaniline.By assembling the device,the composite material obtained by the test has a contrast ratio of 58.8%(at ?=694 nm)and a faster fading speed(coloring time is 1.04 s and the fading time is 1.2 s).Compared with pure polyaniline,the electrochemical performance is significantly improved(3)A Prussian blue film prepared by hydrothermally preparing carbon quantum dots and Prussian blue was prepared by hydrothermal method using trisodium citrate dihydrate as an adjuvant.With the increase of reaction time,the contrast of Prussian blue film increases,the electrochemical performance increases,and the coloring time becomes shorter,which corresponds to the smaller the charge transfer resistance and ion diffusion resistance of the film with longer reaction time in the impedance spectrum Using trisodium citrate as an adjuvant,carbon quantum dots of different proportions were compounded with Prussian blue,and the prepared composite film showed a light to dark blue in appearance.With the increase of carbon quantum dots,the electrochemical performance and electrochromic performance of composite films have also improved.(4)Using glucose as an adjuvant,different ratios of carbon quantum dots and Prussian blue were compounded.The composite thin film prepared was multi-colored in appearance.Through scanning electron microscopy analysis,with the increase of carbon quantum dots,the amount of carbon in the composite was increased.The weight percentage and atomic percentage also increase,and the binding energies of the Fe,N,and C elements in XPS also move in a high direction,which illustrates the successful recombination of carbon quantum dots and Prussian blue.And as the amount of carbon quantum dots increases,a change from yellow to blue can be achieved.The electrochemical properties and electrochromic properties of the prepared composite films have been significantly improved,and the contrast has been significantly increased.