Department of Electronic Engineering, Chang Gung University, 259 Wen-Hwa 1st Road, Kwei-Shan, Taoyuan 333, Taiwan.
Department of Photonics Engineering, Yuan-Ze University, 135 Yuan-Tung Road, Chung-Li, 32003, Taiwan.
Nanoscale. 2016 Mar 14;8(10):5478-87. doi: 10.1039/c5nr07948a.
To improve the omnidirectional light-harvesting in dye-sensitized solar cells (DSSCs), here we present a dandelion-like structure composed of ZnO hemispherical shells and nanorods. Uniformly distributed hemispherical shells effectively suppress the reflection over the broadband region at incident angles up to 60°, greatly improving the optical absorption of the DSSCs. In addition, modulating the length of the ZnO nanorods controls the omnidirectional characteristics of DSSCs. This phenomenon is attributed to the degree of periodicity of the ZnO dandelion-like structures. Cells with shorter rods exhibit a high degree of periodicity, thus the conversion efficiencies of the cells show specific angle-independent features. On the other hand, the cells with longer lengths reveal angle-dependent photovoltaic performance. Along with the simulation, the cells with dandelion-like ZnO structures can couple incident photons efficiently to achieve excellent broadband and omnidirectional light-harvesting performances experimentally, and the DSSCs enhanced the conversion efficiency by 48% at large incident angles. All these findings not only provide further insight into the light-trapping mechanism in these complex three-dimensional nanostructures but also offer efficient omnidirectional and broadband nanostructured photovoltaics for advanced applications.
为了提高染料敏化太阳能电池（DSSC）的全向光捕获性能，我们在此展示了一种由 ZnO 半球壳和纳米棒组成的蒲公英状结构。均匀分布的半球壳在高达 60°的入射角下有效抑制了宽带区域的反射，大大提高了 DSSC 的光吸收。此外，调节 ZnO 纳米棒的长度可以控制 DSSC 的全向特性。这种现象归因于 ZnO 蒲公英状结构的周期性程度。具有较短棒的电池具有较高的周期性，因此电池的转换效率表现出特定的角度无关特征。另一方面，具有较长长度的电池则呈现出角度依赖的光伏性能。通过模拟，具有蒲公英状 ZnO 结构的电池可以有效地耦合入射光子，从而在实验中实现优异的宽带和全向光捕获性能，并且 DSSC 在大入射角下将转换效率提高了 48%。这些发现不仅进一步深入了解了这些复杂三维纳米结构中的光捕获机制，还为先进应用提供了高效的全向和宽带纳米结构光伏器件。
