High-performance counter electrode of carbon nanocubes with embedded cobalt-iron alloy nanoparticles for dye-sensitized solar cells
High-performance counter electrode of carbon nanocubes with embedded cobalt-iron alloy nanoparticles for dye-sensitized solar cells
复制标题
DOI：
10.1016/j.electacta.2018.05.089
复制
发表时间：
2018-07
影响因子：
6.6
通讯作者：
Mao-Sung Wu;H. Shih;Jia Lin
中科院分区：
文献类型：
--
作者：
Mao-Sung Wu;H. Shih;Jia Lin
在合成过程中，高浓度的聚乙烯吡咯烷酮(PVP)有利于六氰亚铁酸钴(CoHCF)纳米立方体的生长。钴-铁(CoFe)合金纳米粒子通过CoHCF粉末的热解被嵌入到碳基质中。PVP在CoHCF中的存在也改变了碳/CoFe复合材料的形态和微观结构。裸露的CoHCF形成竹子状的中空纳米管，而包裹了大量和少量PVP的CoHCF纳米颗粒分别倾向于形成多孔纳米立方体和聚集纳米颗粒。循环伏安和电化学阻抗测试表明，碳-CoFe纳米立方体电极比纳米管、纳米颗粒和铂电极表现出更好的催化性能，这主要是因为它具有较大的比表面积和合适的孔径分布，有利于碘/三碘化合物的偶联。采用纳米立方体对电极的染料敏化太阳能电池的光伏转换效率高达9.20%，高于铂(8.94%)、纳米管(8.48%)和纳米颗粒(8.40%)对电极的光伏转换效率。使用纳米立方体CE的DSSC的性能增强是由于与其他CE相比，嵌入了CoFe纳米颗粒的多孔纳米立方体具有较低的电荷转移阻力。
High concentration of polyvinylpyrrolidone (PVP) favored the growth of cobalt hexacyanoferrate (CoHCF) nanocubes with sharp corners and small particle size during synthesis. The cobalt-iron (CoFe) alloy nanoparticles were embedded in the carbon matrix through pyrolysis of the CoHCF powder. The presence of PVP in CoHCF also changed the morphology and microstructure of the resultant carbon-CoFe composite. Bare CoHCF formed bamboo-like hollow nanotubes, while CoHCF nanoparticles capped with large and small amounts of PVP tended to form porous nanocubes and aggregated nanoparticles, respectively. Cyclic voltammetry and electrochemical impedance measurements indicated that the carbon-CoFe nanocube electrode exhibited better catalytic performance than the nanotube, nanoparticle, and Pt electrodes, mostly due to its higher surface area and suitable pore size distribution for facilitating the iodide/triiodide couple. Dye-sensitized solar cells (DSSCs) employing the nanocube counter electrode (CE) exhibited a high photovoltaic conversion efficiency of 9.20%, which was greater than those obtained using Pt (8.94%), nanotube (8.48%), and nanoparticle (8.40%) CEs. The enhanced performance of the DSSC using the nanocube CE was due to the low charge-transfer resistance of the porous nanocubes with embedded CoFe nanoparticles compared to the other CEs.