双长链烷基Dawson结构钼磷酸复合薄膜的制备、结构及光致变色性质

近年来 ,无机 -有机复合材料由于其独特的结构和特殊的光、电和磁功能特性而引起科研工作者的广泛关注 1,2 ] .杂多化合物为均一的无机多聚物 ,具有笼状结构 ,结构中均有 M3O13三金属氧簇 ,能够接受电子生成杂多蓝或杂多棕 ,加之其在水和有机溶剂中的溶解性和稳定性 ,使其在光电变色材料领域中具有潜在的应用价值 3～ 5] .但这类化合物难于加工成实际应用的器件 ,因而限制了其进一步的应用 .利用有机组分调控的超分子自组装技术可构建光致变色同多酸或杂多酸纳米薄膜材料 ,从而为开发变色响应快、稳定性好、变色可调控的新型光电变色高密…

Preparation, Structure and Photochromic Properties of Dilong-chain Alkyl Group Dawson Type Molybdophosphoric Acid Multicomposite Films

A multicomposite P 2Mo 18 /DODA self assembled multilayer film was fabricated by casting the chloroform solutions of ionic complex between a dimethyldidecylammomium and a phosphomolybdate anion onto the borosilicate glass and calcium fluoride substrates. Infrared spectra revealed that the Dawson strcucture characteristic of the P 2Mo 18 O 6- 62 anion was presented in the composite film. A well ordered superlattice structure, d spacing 3.59 nm, was identified by X ray diffraction. The composite film shows good photochromic properties. Under the irradiation with UV light, the transparent film changed from yellow to blue. Then, bleaching occurred when the film was in contact with ambient air or O 2 in the dark. If the UV irradiated films were stored in nitrogen, helium, argon or vacuum conditions, it could retain blue coloration for a long time. It suggests that oxygen plays an important role during the bleaching process. The photochromic mechanism of the composite film was studied by UV Vis spectra, FTIR spectra and ESR. The appearance of IVCT bands shows that electron transfer occurs between the organic substrate and heteropolyanion, converting heteropolyanions to heteropolyblues with simultaneous oxidation of the organic substrate. Observation of UV induced ESR signal suggests that electron transfer takes place in the lattice and P 2Mo 18 O 6- 62 acting as an acceptor gets electrons during UV irradiation. The changes of IR spectra for the composite film after UV irradiation are another powerful proof to identify the DODA was oxidized and P 2Mo 18 O 6- 62 was reduced in the photochronic process.