碳纳米管负载Ni_2P作为染料敏化太阳能电池对电极的性能研究

Carbon Nanotubes with Ni_2P Nanoparticles as A Counter Electrode for Dye-Sensitized Solar Cells

本文以碳纳米管(CNTs)与Ni2P纳米晶制备CNTs-Ni2P复合材料,首次研究其染料敏化太阳能电池(DSSCs)的光阴极材料性能.使用X射线衍射(XRD)和透射电子显微镜(TEM)测定材料结构,观察材料形貌.结果表明,复合材料由碳纳米管和六方结构的磷化镍构成,无其它磷化物杂相,磷化镍纳米晶(约10 nm)分散于CNTs表面.交流阻抗(EIS)测试显示,与CNTs和Ni2P对电极相比,CNTs-Ni2P对电极的电荷转移电阻和扩散阻抗较低,接近Pt-FTO对电极水平.CNTs-Ni2P对电极的DSSCs光电流达12.9 mA·cm-2,能量转化效率达5.6%,接近Pt-FTO对电极的DSSCs能量转化效率(5.9%).这归因于高电催化活性的磷化镍纳米晶与高电导CNTs的协同效应.

Carbon nanotubes （CNTs） supported by Ni2P nanoparticles were prepared and used as a counter electrode for dye-sensitized solar cells （DSSCs） for the first time. The CNTs-Ni2 P composite was prepared by the heat treatment of a mixed precursor including nickel chloride, sodium hypophosphite and CNTs in argon atmosphere. The X-Ray diffraction （XRD） results indicate that the as-prepared sample consists of hexagonal Ni2 P and carbon nanotubes. No peaks of other nickel phosphides are observed in the XRD pattern. Microstruc-ture of the Ni2P-CNTs composite was investigated using transmission electron microscopy （TEM）. It is shown that the Ni2P nanoparticles with a size of about 10 nm are dispersed on the surface of CNTs. In addition, elec- trochemical impedance spectra （EIS） and photovoltaic conversion performance of counter electrodes for DSSCs are analyzed in detail. It is demonstrated that the Ni2P-CNTs composite presents an obviously low charge-transfer resistance and diffusion impedance as compared with those of individual CNTs and Ni2P. Ac-cordingly, the DSSCs using the composite as a counter electrode have a comparable photovoltaic performance as compared with the conventional FTO/Pt counter electrode, due to the effective combination of the high e-lectrical conductivity of carbon nanotubes and superior electrocatalytic activity of Ni2P nanoparticles.