Investigation of Photo-degradation mechanism of semiconductor-organic material interface

半导体材料现在在各个领域都非常重要。它们的一些性质，如光敏性能，还没有被很好地了解。我们研究了有机材料的光降解，其中包括半导体材料，如小粉末。由于我们对光激发半导体-液体界面的电化学现象有了足够的经验，所以我们采用了光电化学技术。首先，利用有机电极层绝缘的半导体电极测量半导体表面的光催化活性。恒定通孔处的光电流随照射时间的延长而增加，表明在价带形成的光激空穴从有机分子中提取了电子。因此，有机分子被氧化和降解。其次，我们研究了一种新的评价半导体粉末光催化活性的方法--光滑法，该方法可以用来评价包覆了一些疏水性有机分子的半导体粉末的光催化活性。从光收缩速率估计了光催化活性。

Semiconductor materials are now very important in various fields. Some of their properties such as photosensitive properties have not been well understood.We have investigated photodegradation of organic materials in which semiconductor materials such as small powders are included. Since we have enough experiences for electrochemical phenomena of photoexcited semiconductor-liquid interfaces, photoelectrochemical techniques have been employed. At first, photocatalytic activity of semiconductor surface was measured by using of semiconductor electrode insulated with oeganic layers. Photocurrent at the constant applied vias increased with irradiation time indicating that photoexcited holes formed in the valence band extracted electrons from the organic molecules. Therefore, the organic molecules were oxidized and degraded. Secondly we studied a new method named as photosinking for estimation of photocatalytic activity of semiconductor powders which were coated with some organic molecules with hydrophobic character. From the photosinking rate photocatalytic activity has been estimated.