CdS敏化纳晶TiO2薄膜电极的光电化学性能研究/PHOTOELECTROCHEMICAL PROPERTIES OF THE CdS SENSITIZED T
其次采用不同的添加剂对TiO2薄膜电极进行了前处理，并研究了前处理对复合电极光电化学性能的影响。结果表明采用0.1M 尿素和2 g/L PEG的混合溶液对TiO2薄膜电极进行前处理后制得的CdS/TiO2复合电极具有最好的光电化学性能。同时发现前处理对复合电极光电化学性能的影响与复合电极是否进行加热后处理有关。对于进行了加热后处理的复合电极，前处理能同时提高CdS/TiO2复合电极的光电压及光电流；而当复合电极不进行加热后处理时，前处理对光电流及光电压没有产生明显的影响，但却提高了太阳能电池的填充因子。
Dye sensitized solar cells (DSSC) have been an active research project since 1991, and lots of trials have been made in order to enhance its solar energy conversion efficiency. One of the most important approaches is to tuning the absorption spectra of the organic dyes, being anchored onto the TiO2 surface.
The special size-select optical property of the inorganic semiconductor nanocrystal makes it easy to tune the absorption spectrum of inorganic semiconductor particles and thus inorganic semiconductor can be an alternative candidate instead of organic dyes to fabricate a solar cell. Based on this consideration, we prepared the CdS sensitized TiO2 nanocrystal thin film electrode, and its photoelectrochemical properties have been investigated.
TiO2 nanocrystal thin film was prepared by the doctor blade method, and the CdS sensitized TiO2 electrodes were obtained by depositing CdS onto the TiO2 surface via a simple successive ionic layer adsorption reaction technique. The amount of CdS deposited on TiO2 was controlled by the CdS deposition cycle as proved by the UV-Vis spectra. The surface morphology and the crystalline structure were confirmed by SEM and XRD investigations. The CdS was found to be crystallized with cubic crystalline structure in our experiment condition even without heat-treated. It is also found that the CdS particles on the TiO2 surface show to aggregate together depending on the preparation conditions. However, the porous structure of TiO2 film was not affected by the CdS deposition in all the cases, which is a must for constructing an efficient solar cell.
Aiming to improve the photoelectrochemical properties, different kinds of additives were used to pretreat the TiO2 film. The best one was found to be the mixture of 0.1 M of urea and 2 g/L of PEG. Detailed photoelectrochemical investigations show that the pretreatment has different effects depending on whether the CdS/TiO2 was subjected to the post heattreatment or not. A large increase of both photocurrent and photovoltage was found after the pretreatment while the CdS/TiO2 was post-heattreated. In the case of CdS/ TiO2 were not subjected to the post heattreatment, the pretreatment has no obviously effect on both photocurrent and photovoltage. However, the fill factor of the resulted solar cell was largely increased by the pretreatment.