立方体溴化银颗粒光谱增感的电子转移超快动力学研究

Picosecond Ultrafast Kinetic Study of Dyes Sensitized Silver Bromine Microcrystals

本文利用皮秒时间分辨条纹相机技术检测了3种染料在立方颗粒溴化银上吸附后形成聚集体的荧光光谱,分析了3种染料在不同染料浓度下对染料聚集体到溴化银导带的超快电子转移过程的影响,进而分析其对增感效率的影响关系,并探讨了增感过程的微观机理.实验结果表明,荧光衰减的动力学曲线与一个双指数函数拟合得相当好,存在一快一慢两个衰减成分,快衰减成分占拟合较大比例,表明其源于与荧光衰减相竞争的从激发态染料聚集体到AgBr导带的电子转移.光致电子转移的速率及增感效率随着染料相对浓度的增加表现出一定的变化趋势,染料浓度增加,增感效率减小.

On the basis of Streak Camera technique, fluorescence spectroscopy of three kinds of dyes J-aggregate adsorbed on cubic AgBr microcrystals was detected in time resolve 5 10s. The dependence of ultrafast electron transfer from dye J-aggregate to conduction band of AgBr on different dyes with different concentration was analyzed. And the micro mechanism of sensitization was also analyzed. It is showed that the dynamic decay curves can be fitted well by a double-exponential function. The fitting curves are consisted of a fast component and a slow one. Because of the large amplitude of the fast component, the fast decay should be mainly attributable to the electron transfer from J-aggregate of dye to conduction band of AgBr. The photo-induced electron transfer rate and the sensitization efficiency show certain change tendency with the change of dye concentration. As the dye concentration increasing, the sensitization efficiency decreases.