Efficient conversiton of light energy by using funational semiconductor surfaces

基于半导体液结的能量转换系统一直专注于燃料生产和电能生产。当半导体电极接收到能量大于其带隙的光子时，在空间电荷层中会产生电子-空穴对。在n型半导体的情况下，空间电荷层中存在的电场将光生空穴驱动到界面区域，并将电子驱动到电极的内部。我们首次用n型二氧化钛电极与铂黑电极连接的系统论证了太阳能光电解水的可能性，构建了将水分解为H2和O2的高效光电化学电池，以及构建高效的再生光伏电池，其中一个共同的氧化还原电偶在光阳极和金属阴极上反应。以下三个主题进行了研究：1)利用负载催化金属的半导体表面来提高转换效率；2)用分离因子法确定光催化半导体表面的反应位置；3)用化学修饰和聚合物涂层对半导体表面进行表面修饰。

Lihhy rnergy conversion systems based on the semiconductor liquid junctions have been focusing on fuel production as well as electrical energy generation.When a semiconductor electrode receives photons with energy greater than its band gap, electron-hole pairs are generated within a space charge layer. In the case of an n-type semiconductor, electric field existing within the space charge layer drives photo- generated holes toward the interfacial region and electrons toward the interior of the electrode. Thus, by combining a semiconductor electrode with an appropriate counter-electrode, a photo-cell can be constructed.The possibiliy of solar photoelectrolysis of water was demonstrated by us for the first time with a system in which an n-type titanium dioxide electrode was connected to a platinum black electorde, construction of an efficient photoelectrochemical cell in which water is decomposed to H2 and O2, as well as for the construction of an efficient regenerative photovoltaic cell in which a common redox couple is reacting at both the photoanode and the metal cathode.Following three subjects have been studiel.1) Increase of conversion efficiency by using semiconductor surfaces loaded with catalytic metals2) determination of reaction sites of photocatalytic semiconductor surfaces by separation factor method3) surface modification of semiconductor surface with chemical modification and polymer coating.