N3敏化Ho3+离子修饰TiO2纳米晶电极的光电化学性质

研究了Ho3+离子表面修饰对TiO2纳米晶电极光电性能的影响. TiO2表面氧化钬的存在一方面降低了染料和TiO2之间的电子注入速率, 而另一方面它也能够抑制电荷复合. 结果表明, 在TiO2纳米晶薄膜表面修饰一定厚度的Ho3+离子层, 在电极表面就形成了一个势垒, 能够有效抑制电极表面的电荷复合, 从而提高了染料敏化太阳能电池的光电压和光电转化效率. 在93.1 mW·cm-2白光照射下, TiO2/Ho-0.1 和TiO2/Ho-0.2(0.1 和0.2分别是修饰TiO2电极的Ho3+溶液的浓度, 单位是mol·L-1)两个电极的光电转化效率分别达到8.3%和7.6%, 与TiO2电极(7.2%)比较, 分别增大了15%和5%.

Photoelectrochemical Properties of N3 Sensitized Ho3+ Modified TiO2 Nanocrystalline Electrodes

Effects of Ho3+ ion modification on photoelectrical properties of TiO2 electrodes were investigated. On the one hand, the Ho3+ layer decreased electron injection between the dye and TiO2, but on the other hand, it suppressed charge recombination. Experimental results showed that an energy barrier was formed when the TiO2 electrode was modified with a Ho3+ layer of a certain thickness. This energy barrier efficiently suppressed charge recombination. As a result, the photovoltage and photoelectrical conversion efficiency were improved under optimal conditions. Photoelectrical conversion efficiencies of TiO2/Ho-0.1 and TiO2/Ho-0.2 (0.1 and 0.2 are the concentrations of Ho3+ solution used for modification, mol·L-1) electrodes reached 8.3%and 7.6%, respectively, under illumination with white light at 93.1 mW·cm-2. This represents an increase of about 15% and 5%, respectively, compared to a bare TiO2 electrode (7.2%).