A novel inorganic-organic nanocomposite film was prepared and characterized by IR, UV-Vis, XRD and DTA-TG. IR and UV-Vis spectra show that the Keggin structure of SiW 12O 4- 40 polyanion is preserved in the composite ...A novel inorganic-organic nanocomposite film was prepared and characterized by IR, UV-Vis, XRD and DTA-TG. IR and UV-Vis spectra show that the Keggin structure of SiW 12O 4- 40 polyanion is preserved in the composite film and there is an interaction between H 4SiW 12O 40 and the organic substrate. The composite film showed a reversible photochromism. Under UV irradiation, the composite film turns blue and charge transfer occurs by oxidation of R-NH + 3 and reduction of SiW 12O 4- 40. When the irradiated samples are placed in air and sheltered from the light, they change back to their original color, and recover again when being exposed to UV light.展开更多
Porous silicon (PS) fabricated by anodizing have recently become the subject of intense interest due to their room temperature visble light emission properties.However, highly porous silicon made by electrochemical et...Porous silicon (PS) fabricated by anodizing have recently become the subject of intense interest due to their room temperature visble light emission properties.However, highly porous silicon made by electrochemical etching is fragile and tends to craze during normal drying in air after taken out from HF based solution. The preparation of highly porous materials by sol-gel processing followed by supercritical drying was carried out by Kistler in 1931. Since 1985, the sucpercritical drying (SD) has been used successfully to prepare a variety of aerogels, comprising a void fraction of more than 90%. This technigue has now been applied to prepare luminescent porous silicon on both <100> and <111> C-Si substrates. Porosities up to 94% have been achieved, which were determined by gravimetric measurement. Its morphological feature, microstructure and photoluminescence properties exhibit novel characteristics from those conventionally anodized porous silicon. It has been demonstrated that anodization and supercritical drying can yield ultra-high porous luminescent PS with minimal damage and much higher degree of perfection than that of previously attained. It is very interested that the PL intensity may be inproved by SD method.展开更多
Silicon clusters are produced by a new chendcal method. Comparing with theprepaxation method using laser evaporation, large amoun of silicon clusters could havebeen obtained by this cheforcal decomposition of silicane...Silicon clusters are produced by a new chendcal method. Comparing with theprepaxation method using laser evaporation, large amoun of silicon clusters could havebeen obtained by this cheforcal decomposition of silicane and the clusters produced is sta-ble in atm0sphere. The FAB-MS spectra of the clusters is also discussed in this paper.展开更多
A series of naphthopyrans with hydrazone unit （8a-8m）, were synthesized and characterized by 1H NMR, 13C NMR, IR and HRMS. The photochromic properties were investigated under continuous irradiation, in particular re...A series of naphthopyrans with hydrazone unit （8a-8m）, were synthesized and characterized by 1H NMR, 13C NMR, IR and HRMS. The photochromic properties were investigated under continuous irradiation, in particular re- gard to the fatigue resistance and the lifetime of the colored open form in solution and polymers. The results showed that these compounds had both good photochromic properties and high fatigue resistance. Detailed studies showed that representative compound 8d （3,3-di-4-methoxybenzoic acid methylenehydrazino-[3H]-naphtho [2,1-b]pyran） had good photochromic properties in THF solution, in solid state, and in polymers, and exhibited a significant ba- thochromic shift in the spectra of the open forms compared to known naphthopyrans 9 （3,3-diphenyl-[3H]- naphtho[2,1-b]pyran）. On the other hand, the higher melting points of target compounds are promising for the polymer film preparation through hot-melt method.展开更多
文摘A novel inorganic-organic nanocomposite film was prepared and characterized by IR, UV-Vis, XRD and DTA-TG. IR and UV-Vis spectra show that the Keggin structure of SiW 12O 4- 40 polyanion is preserved in the composite film and there is an interaction between H 4SiW 12O 40 and the organic substrate. The composite film showed a reversible photochromism. Under UV irradiation, the composite film turns blue and charge transfer occurs by oxidation of R-NH + 3 and reduction of SiW 12O 4- 40. When the irradiated samples are placed in air and sheltered from the light, they change back to their original color, and recover again when being exposed to UV light.
文摘Porous silicon (PS) fabricated by anodizing have recently become the subject of intense interest due to their room temperature visble light emission properties.However, highly porous silicon made by electrochemical etching is fragile and tends to craze during normal drying in air after taken out from HF based solution. The preparation of highly porous materials by sol-gel processing followed by supercritical drying was carried out by Kistler in 1931. Since 1985, the sucpercritical drying (SD) has been used successfully to prepare a variety of aerogels, comprising a void fraction of more than 90%. This technigue has now been applied to prepare luminescent porous silicon on both <100> and <111> C-Si substrates. Porosities up to 94% have been achieved, which were determined by gravimetric measurement. Its morphological feature, microstructure and photoluminescence properties exhibit novel characteristics from those conventionally anodized porous silicon. It has been demonstrated that anodization and supercritical drying can yield ultra-high porous luminescent PS with minimal damage and much higher degree of perfection than that of previously attained. It is very interested that the PL intensity may be inproved by SD method.
文摘Silicon clusters are produced by a new chendcal method. Comparing with theprepaxation method using laser evaporation, large amoun of silicon clusters could havebeen obtained by this cheforcal decomposition of silicane and the clusters produced is sta-ble in atm0sphere. The FAB-MS spectra of the clusters is also discussed in this paper.
基金Project supported by the National Natural Science Foundation of China （Nos. 20971071, 20602020）.
文摘A series of naphthopyrans with hydrazone unit （8a-8m）, were synthesized and characterized by 1H NMR, 13C NMR, IR and HRMS. The photochromic properties were investigated under continuous irradiation, in particular re- gard to the fatigue resistance and the lifetime of the colored open form in solution and polymers. The results showed that these compounds had both good photochromic properties and high fatigue resistance. Detailed studies showed that representative compound 8d （3,3-di-4-methoxybenzoic acid methylenehydrazino-[3H]-naphtho [2,1-b]pyran） had good photochromic properties in THF solution, in solid state, and in polymers, and exhibited a significant ba- thochromic shift in the spectra of the open forms compared to known naphthopyrans 9 （3,3-diphenyl-[3H]- naphtho[2,1-b]pyran）. On the other hand, the higher melting points of target compounds are promising for the polymer film preparation through hot-melt method.
