School of Chemistry and Bio21 Institute, The University of Melbourne, Parkville, Victoria 3010, Australia.
ACS Nano. 2012 Jul 24;6(7):5995-6004. doi: 10.1021/nn3009189. Epub 2012 Jun 20.
Alloying is a versatile tool for engineering the optical and electronic properties of materials. Here, we explore the use of CdTe and CdSe nanocrystals in developing sintered CdSe(x)Te(1-x) alloys as bandgap tunable, light-absorbing layers for solution-processed solar cells. Using a layer-by-layer approach, we incorporate such alloyed materials into single- and graded-composition device architectures. Nanostructured solar cells employing CdSe(x)Te(1-x) layers are found to exhibit a spectral response deeper into the IR region than bulk CdTe devices as a result of optical bowing and achieve power conversion efficiencies as high as 7.1%. The versatility of the layer-by-layer approach is highlighted through the fabrication of compositionally graded solar cells in which the [Se]:[Te] ratio is varied across the device. Each of the individual layers can be clearly resolved through cross-sectional imaging and show limited interdiffusion. Such devices demonstrate the importance of band-alignment in the development of highly efficient, nanostructured solar cells.
合金是工程材料光学和电子性能的通用工具。在这里，我们探索了使用 CdTe 和 CdSe 纳米晶体来开发烧结的 CdSe(x)Te(1-x) 合金作为带隙可调、光吸收层，用于溶液处理的太阳能电池。我们使用逐层方法将这些合金材料纳入单组分和分级组分器件结构中。纳米结构太阳能电池采用 CdSe(x)Te(1-x) 层，由于光学弓曲的作用，其光谱响应比体相 CdTe 器件更深地进入 IR 区域，并实现高达 7.1%的功率转换效率。通过在器件中改变 [Se]:[Te] 比来制造成分梯度太阳能电池，突出了逐层方法的多功能性。通过横截面成像可以清楚地分辨每个单独的层，并且显示出有限的互扩散。这些器件证明了能带排列在开发高效、纳米结构太阳能电池中的重要性。
