Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, P. R. China.
Nanoscale. 2012 May 21;4(10):3154-61. doi: 10.1039/c2nr12089e. Epub 2012 Apr 10.
ZnO/Zn(1-x)Pb(x)Se core-shell nanowires (NWs) have been synthesized by a solution based surface ion transfer method at various temperatures. The energy dispersive spectroscopic (EDS) mapping of single NWs suggests that the Zn, Pb and Se atoms are uniformly distributed in their shell layers. The ternary Zn(1-x)Pb(x)Se layers with tunable bandgaps extend the band-edge of optical absorption from 450 nm to 700 nm contrasting with the binary ZnSe layers. The ultraviolet photoelectron spectroscopic (UPS) analysis reveals a transition from the type I to type II band alignment when the x fraction decreases from 0.66 to the value of 0.36 in the nanoshell layers. This quantitative investigation of electronic energy levels at ZnO and Zn(1-x)Pb(x)Se interfaces indicates that the proper type II band alignment is well suited for photovoltaic energy conversion. The photovoltaic cells comprising a ZnO/Zn(1-x)Pb(x)Se nano-heterojunction with the optimized Pb content are expected to be more efficient than the devices sensitized by binary ZnSe or PbSe.
ZnO/Zn(1-x)Pb(x)Se 核壳纳米线 (NWs) 通过在不同温度下的基于溶液的表面离子转移方法合成。单根 NWs 的能量色散光谱 (EDS) 映射表明，Zn、Pb 和 Se 原子在其壳层中均匀分布。可调带隙的三元 Zn(1-x)Pb(x)Se 层将光学吸收的能带边缘从 450nm 扩展到 700nm，与二元 ZnSe 层形成对比。紫外光电子能谱 (UPS) 分析表明，当纳米壳层中的 x 分数从 0.66 降低到 0.36 时，从 I 型能带排列到 II 型能带排列发生转变。对 ZnO 和 Zn(1-x)Pb(x)Se 界面的电子能级的定量研究表明，适当的 II 型能带排列非常适合光伏能量转换。包含优化 Pb 含量的 ZnO/Zn(1-x)Pb(x)Se 纳米异质结的光伏电池预计比用二元 ZnSe 或 PbSe 敏化的器件效率更高。
