Primary Processes in Photoconductivity Studied by Electromodulation Spectroscopy.

研制了一种高灵敏度的分光光度计，其吸光度分辨率高达10-5。它已被证明是一种强大的研究工具，可以用来确定由外加电场引起的微小吸光度变化。研究了x-型H_2酞菁的电吸收光谱。结果表明，在第一个吸收峰表现出较大电调制度的邻位花青素往往具有较高的载流子产生效率。此外，还研究了电场对荧光的调制作用。结果清楚地表明，调制不是由于外加电场，而是由于电极注入的电荷。由注入电荷引起的异常强度猝灭似乎表明，具有CT态特征的最低激发态在注入电荷周围的强场中解离。总的来说，CT态在所研究的材料中参与了光载流子的产生、光吸收的调制和荧光的调制。

A highly sensitive spectrophotometer has been developed, which has a resolution in absorbance as high as 10-5. It has proved to be a powerful research tool in determioning minute absorbance changes by, e. g. , an applied electric field. The electroabsorption spectrum of x-form H_2 Phthalocyanine has been investigated. The results indicate phtahlocyanines that exhibit a large electromodulation in their first absorption peak tend to have high efficiency of charge carrier generation.Also, modulation of fluorescence by an electric field has been studied. The results clearly show that the modulation is not due to an applied field, but due to charges injected from the electrodes. The anomalously sttong quenching due to injected charge seems to indicate that the lowest excited singlet state, which has a CT state character, disociates in the strong field surrounding the injected charges.As a whole, important participation of CT states in photocarrier generation, modulation of light absorption, and fluorescence, odulation, in the materials studied has been clarified.