Chemical Conversion Synthesis of ZnS Shell on ZnO Nanowire Arrays: Morphology Evolution and Its Effect on Dye-Sensitized Solar Cell
Chemical Conversion Synthesis of ZnS Shell on ZnO Nanowire Arrays: Morphology Evolution and Its Effect on Dye-Sensitized Solar Cell
复制标题
ZnO纳米线阵列上ZnS壳的化学转化合成：形貌演变及其对染料敏化太阳能电池的影响
DOI：
10.1021/am201425n
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发表时间：
2012-01-01
影响因子：
9.5
通讯作者：
Cheng, Yinfen
中科院分区：
文献类型：
--
作者：
Liu, Lizhu;Chen, Yiqing;Cheng, Yinfen
采用水热沉积和液相化学转化相结合的简单两步法，成功制备了异质结构ZnO/ZnS核/壳纳米线阵列，用作染料敏化太阳能电池（DSSC）的光阳极。通过改变化学转化过程中的反应时间，系统地研究了ZnS包覆在ZnO纳米线上的形貌演变及其对DSSC性能的影响。结果表明，致密的ZnS壳层能有效地促进染料分子光生电子向ZnO导带的转移，同时抑制染料分子和氧化还原电解质注入电子的复合。随着反应时间的延长，纳米线表面由于ZnS纳米颗粒的形成而变得粗糙，这将提高染料负载量，导致短路电流密度（J（SC））增加。开路光电压衰减测量也表明，在ZnO/ZnS核/壳纳米结构中的电子寿命（τ（n））可以显着延长，因为在ZnS涂层后的ZnO中的较低的表面陷阱密度。对于ZnO/ZnS核/壳纳米结构，J（SC）和η在6 h转化时间后可达到最大值8.38 mA/cm（2）和1.92%，分别对应于合成的ZnO的12倍和16倍的增量。
Heterostructured ZnO/ZnS core/shell nanowire arrays have been successfully fabricated to serve as photoanode for the dye-sensitized solar cells (DSSCs) by a facile two-step approach, combining hydrothermal deposition and liquid-phase chemical conversion process. The morphology evolution of the ZnS coated on the ZnO nanowires and its effect on the performance of the DSSCs were systematically investigated by varying the reaction time during the chemical conversion process. The results show that the compact ZnS shell can effectively promote the photogenerated electrons transfer from the excited dye molecules to the conduction band of the ZnO, simultaneously suppress the recombination for the injected elelctrons from the dye and the redox electrolyte. AS reaction time goes by, the surface of the nanowires becomes coarse because of the newly formed ZnS nanoparticles, which will enhance the dye loading, resulting in increment of the short-circuit current density (J(SC)). Open-circuit photovoltage decay measurements also show that the electron lifetime (tau(n)) in the ZnO/ZnS core/shell nanostructures can be significantly prolonged because of the lower surface trap density in the ZnO after ZnS coating. For the ZnO/ZnS core/shell nanostructures, the J(SC) and eta can reach a maximum of 8.38 mA/cm(2) and 1.92% after 6 h conversion time, corresponding to 12- and 16-fold increments of as-synthesized ZnO, respectively.