Photochromism And Holographic Storage Of Low-dimensional Carbon/Titanium Dioxide Composite

Nowadays,high-density optical information storage and encryption readout have become one of the core subjects in Big-Data era,which can effectively deal with data expansion,cloud computing,and storage security of massive data.Photochromic materials are regarded as important optical information storage media.Among them,inorganic materials have better photothermal stability and biological safety.In recent years,titania?TiO₂?/noble metal photochromic material system is proposed,working as the principle of plasmon-induced charge separation?PICS?.However,the preparation cost is relatively high.How to find and develop a cost-effective material which can realize high-density information storage and encryption readout of information has become a major challenge in the field.Carbon is one of the elements which are most closely related to human beings.It can form a vast number of compounds.The resultant carbon-based materials show extraordinary physical and chemical properties,occupying an important position in the development of photoelectric information science and technology.Recently,graphene oxide?GO?/TiO₂ composite systems were found to show photochromic properties.Besides,electron transfer between carbon dots?CDs?and TiO₂ has been proposed.Carbon materials are easier to be obtained and cost-effective.And the system has the possibility of realizing high-density information storage and encrypted readout.The exploration of low-dimensional carbon/TiO₂ films will expand new directions for finding materials which are cost-effective and can be used for advanced information processing technology,broadening the related research fields of carbon materials.The thesis focuses on the photochromism and holographic storage of low-dimensional carbon/TiO₂ composite films,as follows:1.For the first time,introducing weak acid molecules into GO/TiO₂ films by “Immersion-Dropping” method.The weak acid molecules cooperate with TiO₂ to release sufficient electrons,realizing the reconstruction of color holograms from violet to yellow regions.The "diffraction self-enhancement" effect of the GO/TA-TiO₂ film is also observed.This work provides a new idea for the large-capacity information storage and color display equipment,opening a new way for the functionalization of such carbon-based films in optoelectronic devices.2.To the best of our knowledge,it is the first time to find that under the single light source irradiation,CDs/TiO₂ composite system prepared by immersion anchoring?IA?and dropping anchoring?DA?exhibits “bidirectional photochromism”?i.e.,coloration or decoloration?.Both anchoring films are sensitive to wavelength and polarization.And the IA-CDs/TiO₂ film has a high degree of wavelength/polarization sensitivity,which is expected to be used as a wavelength/polarization indicator,providing a new dimension for the encryption and storage of optical information.Films of the two assembly methods have photoinduced birefringence,which can increase the information storage capacity through multiplexing.3.The IA-CDs/TiO₂ film has the characteristic of photoinduced birefringence.With the effective modulation of the amplitude and phase of optical information by the electrons in the excited state of CDs,the operation of the XNOR gate of the all-optical logic is realized.And the application of the all-optical logic of carbon-based films is investigated.The work mentioned above provides a new material platform for information storage,display and processing,indicating an important basis for the development of new functional integrated devices.