AgCl微晶的染料增感吸收光谱特性研究

Absorption Spectra Characteristic of the Dye-sensitized AgCl Microcrystal

尽管基于卤化银晶体的照相胶片已基本退出市场,但是卤化银晶体在光催化、LED活性物质等方面仍有广泛应用。提高卤化银晶体利用效率的关键在于扩展其吸收波段。本文在制备Ag Cl立方体微晶的基础上,研究了染料增感对Ag Cl乳剂吸收光谱的影响。结果表明:纯Ag Cl晶体仅在小于408nm的紫外波段有强吸收,而染料增感Ag Cl乳剂则在蓝绿光吸收波段出现明显增感吸收,且吸收峰的位置相对染料的单分子吸收峰分别发生了蓝移和红移。基于染料分子在晶体界面的聚集吸附模型和激子理论定性地解释了增感吸收峰发生偏移的现象。

Though the silver halide photographic films have drop out of the market, the silver halide microcrystal has also been widely applied as photocatalyst, active material in LED, and so on. Key factor for enhancing the effect of silver halide is laid on widening its absorption band. In this article, the cubic AgCl microcrystal is synthesized, and the dye-sensitized AgCl emulsion is focused on for its absorption property. Results indicate that the efficient absorption appears at the range with wavelength below 408nm for the pure AgCl microcrystal. For the dye-sensitized AgCl emulsion, sensitization absorption spectra at blue and green band is appeared, which is related to the absorption of dye molecules, though the absorption peaks have been blue- and red-shifted, respectively. Such phenomenon is qualitatively analyzed based on the aggregate adsorption model of dye molecules on the microcrystal surface and the exciton theory