Hierarchical weeping willow nano-tree growth and effect of branching on dye-sensitized solar cell efficiency
Hierarchical weeping willow nano-tree growth and effect of branching on dye-sensitized solar cell efficiency
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DOI：
10.1088/0957-4484/23/19/194005
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发表时间：
2012-05-17
期刊：
影响因子：
3.5
通讯作者：
Ko, Seung Hwan
中科院分区：
文献类型：
--
作者：
Herman, Indria;Yeo, Junyeob;Ko, Seung Hwan
在本文中，我们展示了简单、低成本、低温、水热生长具有很长分支的垂柳ZnO纳米树，以实现高效染料敏化太阳能电池（DSSC）。我们还讨论了分支对太阳能电池效率的影响。通过在主干 ZnO 纳米线 (NW) 上引入分支生长，分支 ZnO NW DSSC 的短路电流密度和整体光转换效率几乎增加到垂直生长 ZnO NW 的四倍。效率的提高归因于表面积的增加以实现更高的染料负载和光捕获，并且还归因于通过沿着结晶 ZnO 分支的直接传导减少电荷重组。随着分支长度的增加，分支变得松弛，太阳能电池效率的增加减慢，因为有效表面积的增加受到干燥过程中分支成束和随后染料负载减少的阻碍。
In this paper we have demonstrated the simple, low cost, low temperature, hydrothermal growth of weeping willow ZnO nano-trees with very long branches to realize high efficiency dye-sensitized solar cells (DSSCs). We also discuss the effects of branching on solar cell efficiency. By introducing branched growth on the backbone ZnO nanowires (NWs), the short circuit current density and the overall light conversion efficiency of the branched ZnO NW DSSCs increased to almost four times that for vertically grown ZnO NWs. The efficiency increase is attributed to the increase in surface area for higher dye loading and light harvesting and also to reduced charge recombination through direct conduction along the crystalline ZnO branches. As the length of the branches increased, the branches became flaccid and the increase in solar cell efficiency slowed down because the effective surface area increase was hindered by branch bundling during the drying process and subsequent decrease in the dye loading.