Wei Liguo, Chen Shishan, Yang Yulin, Dong Yongli, Song Weina, Fan Ruiqin
College of Environmental and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin 150022, P. R. China.
Precious Tyrone New Materials Co., LTD., Qitaihe 154603, P.R. China.
J Nanosci Nanotechnol. 2018 Feb 1;18(2):976-983. doi: 10.1166/jnn.2018.14186.
Graphene has attracted a lot of attention because of its unique mechanical, thermal, electrical and optical properties. In this study, a double layered structured photoanode consisting of a graphene/TiO2 composite layer and a TiO2 nanoparticles (P25) underlayer was developed. The photoelectric properties of as-prepared double layer structured photoanode were studied with comparison of the anatase TiO2 photoanode. Graphene was prepared by reduction of graphene oxide (GO) under a hydrothermal conditions and graphenen/TiO2 composite semiconductor materials were prepared by mixing graphene into TiO2 paste. The effect of graphene contents in graphene/TiO2 composite layer was also investigated. After constructing double layer photoanode with proper amount of graphene, the photoanode displayed enhanced light and dye adsorption properties with higher light harvesting efficiency, lower internal resistances, faster electron transport and lower charge recombination rate, which resulted in high current density. At the optimum conditions, the DSSC exhibited a Jsc of 15.01 mA cm-2, a Voc of 0.72 V, and a FF of 0.66 with the energy conversion efficiency (η) of 7.08%, indicating a increase in Jsc and η respectively than that of DSSC based on pure TiO2 photoanode, which gives a Jsc of 13.25 mA cm-2, a Voc of 0.73 V, and a FF of 0.62 with a η of 5.94%. However, the addition of excess graphene in the composite layer led to the enhancement of charge recombination, the reduction of dye adsorption and the decrease of photoelectric conversion efficiency of DSSCs. The graphene/TiO2 composite layer in DSSCs could really enhance its efficiency after the amount of graphene was successfully optimized.
石墨烯因其独特的机械、热、电和光学性能而备受关注。在本研究中，开发了一种由石墨烯/TiO₂复合层和TiO₂纳米颗粒（P25）底层组成的双层结构光阳极。通过与锐钛矿TiO₂光阳极比较，研究了所制备的双层结构光阳极的光电性能。在水热条件下通过还原氧化石墨烯（GO）制备石墨烯，并将石墨烯混入TiO₂浆料中制备石墨烯/TiO₂复合半导体材料。还研究了石墨烯/TiO₂复合层中石墨烯含量的影响。在构建含有适量石墨烯的双层光阳极后，该光阳极表现出增强的光和染料吸附性能，具有更高的光捕获效率、更低的内阻、更快的电子传输和更低的电荷复合率，从而产生高电流密度。在最佳条件下，染料敏化太阳能电池（DSSC）的短路电流密度（Jsc）为15.01 mA cm⁻²，开路电压（Voc）为0.72 V，填充因子（FF）为0.66，能量转换效率（η）为7.08%，这表明与基于纯TiO₂光阳极的DSSC相比，Jsc和η分别有所增加，后者的Jsc为13.25 mA cm⁻²，Voc为0.73 V，FF为0.62，η为5.94%。然而，在复合层中添加过量的石墨烯会导致电荷复合增强、染料吸附减少以及DSSC的光电转换效率降低。在成功优化石墨烯用量后，DSSC中的石墨烯/TiO₂复合层确实可以提高其效率。
