Inorganic–organic Hybrid Photochromic Materials:Syntheses And Properties

Photochromic materials that undergo light induced reversible color change,have drawn increasing attention due to their real or potential applications in various fields,including reversible optical switching,information storage systems,solar energy conversion,display,and so on.There is growing interest in photochromic inorganic–organic hybrid materials,which can combine the advantages of inorganic and organic components and have the ability to apply synergistic effects between inorganic and organic components.In this paper,building inorganic-organic hybrid photochromic crystalline materials is the research object.(1)two such photochromic species can be compounded into an inorganic–organic hybrid,in which the advantages of polyoxometalates and photochromic viologens are combined at the molecular level,through electrostatic attractions or weak interactions.(2)The photochromic materials was constructed by introducing electron acceptor(A)to the metal-electron donor(D)MOF framework.New families of photochromic species with non-photochromic components may offer opportunities to obtain diverse photochromic materials.The main results of this paper work are as follows:1.A viologens-polyoxometalates hybrid compound has been solvothermally synthesized,which exhibits reversible photochromism,interesting photoluminescence and photovoltaic activity.This compound shows a long-lived charge-separated state upon UV irradiation,which can be stable in the dark at least one month with no obvious change.Compound 1 as a multifunctional controllable-photoresponsive material is promising for potential application in optical switches,reversible memory devices,solar energy conversion material and other photosensitive advanced materials.2.A new electron transfer type photoactive host–guest supramolecule was constructed by introducing(CH3)2NH2+ cations to the MOF framework.The resulting compound 2 exhibits reversible photochromic property without using photochromic components,resulting from photoinduced electron-transfer between the electron-rich anionic framework and the electron-deficient guest ions.In addition,a photoluminescence “on/off switch” occurs during the coloration–decoloration process.The raw materials are non-poisonous and harmless,hence compound 2 may be more cost-effective,clean,and harmless to the heath than existing photochromic materials.