Department of Physics, ‡Department of Electrical Engineering, §Department of Materials Science and Engineering, and ∥Department of Applied Physics Stanford University , Stanford, California 94305, United States.
Nano Lett. 2013 Oct 9;13(10):4850-6. doi: 10.1021/nl402680g. Epub 2013 Sep 16.
Nanostructures have been widely used in solar cells due to their extraordinary optical properties. In most nanostructured cells, high short circuit current has been obtained due to enhanced light absorption. However, most of them suffer from lowered open circuit voltage and fill factor. One of the main challenges is formation of good junction and electrical contact. In particular, nanostructures in GaAs only have shown unsatisfactory performances (below 5% in energy conversion efficiency) which cannot match their ideal material properties and the record photovoltaic performances in industry. Here we demonstrate a completely new design for nanostructured solar cells that combines nanostructured window layer, metal mesa bar contact with small area, high quality planar junction. In this way, we not only keep the advanced optical properties of nanostructures such as broadband and wide angle antireflection, but also minimize its negative impact on electrical properties. High light absorption, efficient carrier collection, leakage elimination, and good lateral conductance can be simultaneously obtained. A nanostructured window cell using GaAs junction and AlGaAs nanocone window demonstrates 17% energy conversion efficiency and 0.982 V high open circuit voltage.
由于其非凡的光学特性，纳米结构在太阳能电池中得到了广泛的应用。在大多数纳米结构电池中，由于增强了光吸收，获得了高短路电流。然而，它们中的大多数都存在开路电压和填充因子降低的问题。其中一个主要挑战是形成良好的结和电接触。特别是，GaAs 中的纳米结构仅表现出令人不满意的性能（能量转换效率低于 5%），无法与其理想的材料性能和工业中创纪录的光伏性能相匹配。在这里，我们展示了一种用于纳米结构太阳能电池的全新设计，它结合了纳米结构窗口层、具有小面积和高质量平面结的金属台面条接触。通过这种方式，我们不仅保留了纳米结构的先进光学特性，如宽带和宽角度抗反射，还最大限度地减少了其对电特性的负面影响。可以同时获得高光吸收、高效载流子收集、漏电流消除和良好的横向电导。使用 GaAs 结和 AlGaAs 纳米锥窗口的纳米结构窗口电池实现了 17%的能量转换效率和 0.982V 的高开路电压。
