不同状态蒽的荧光特性

本文利用时间相关单光子计数技术,系统地测量了不同状态(蒽溶液、蒽单晶、蒽的真空蒸膜)的荧光寿命,给出了较精确值。得到了在室温下蒽/乙醇,蒽/苯的荧光寿命随浓度增加变短,而在固态样品中,蒽的寿命变长,对于蒽单晶为15.3ns,而对蒽真空蒸膜为19.1ns,并且,在溶液样品中,不同峰值的荧光寿命基本相同。 还系统测量了蒽在不同状态下的激发谱和发射谱,观察到在固体状态下谱线加宽,并有较大红移。 我们观察到蒽/乙醇,蒽/苯随着浓度的变化其激发谱有明显的变化,而它的发射谱基本保持不变。

FLUORESCENCE PROPERTIES OF ANTHRACENCE IN DIFFERENT STATES

The fluorescence lifetime of anthracence in three different states (solution, crystal, thin film) have been systematically measured by means of single-photon counting technique. Because there are a few disadvantagous factors: 1) finite time width of the excitation source; 2) transit time divergency of photomultiplier; 3) finite response time of electronic systems. These factors have been removed by deconvolution method and then accurate lifetime values have been obtained. We have got following conclusions: i) the lifetime of anthracence in benzene and ethanol shorten with increase of the concentration (Table 1) and they are approximately the same for different emission peaks in the solutions; ii) the lifetimes of anthracence in the solids are longer than that in the solutions. (τ=15.3ns for the crystal, τ=19.lns for the thin film).The excitation, emission spectra have been measured in the different states. It is observed that there are widening of emission bands and red shift of emission peaks in the solids. There are greater change for the excitation spectra and much smaller for the emission spectra with the increase of the concentration.It is considered that the lifetimes shortened with the increase of the concentration come from concentration quenching. The obvious change for the excitation spectra in different concentration may be originated from the interaction between different condensed anthracence molecule states.