Kim Ganghun, Dominguez-Caballero Jose A, Lee Howard, Friedman Daniel J, Menon Rajesh
Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, Utah 84112, USA.
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Phys Rev Lett. 2013 Mar 22;110(12):123901. doi: 10.1103/PhysRevLett.110.123901. Epub 2013 Mar 21.
In this Letter, we report the preliminary demonstration of a new paradigm for photovoltaic power generation that utilizes a broadband diffractive-optical element (BDOE) to efficiently separate sunlight into laterally spaced spectral bands. These bands are then absorbed by single-junction photovoltaic cells, whose band gaps correspond to the incident spectral bands. We designed such BDOEs by utilizing a modified version of the direct-binary-search algorithm. Gray scale lithography was used to fabricate these multilevel optics. They were experimentally characterized with an overall optical efficiency of 70% over a wavelength range of 350-1100 nm, which was in excellent agreement with simulation predictions. Finally, two prototype devices were assembled: one with a pair of copper indium gallium selenide based photovoltaic devices, and another with GaAs and c-Si photovoltaic devices. These devices demonstrated an increase in output peak electrical power of ∼ 42% and ∼ 22%, respectively, under white-light illumination. Because of the optical versatility and manufacturability of the proposed BDOEs, the reported spectrum-splitting approach provides a new approach toward low-cost solar power.
在本信函中，我们报告了一种用于光伏发电的新范式的初步演示，该范式利用宽带衍射光学元件（BDOE）将太阳光有效地分离成横向间隔的光谱带。然后，这些光谱带被单结光伏电池吸收，其带隙与入射光谱带相对应。我们通过使用直接二进制搜索算法的改进版本来设计此类BDOE。采用灰度光刻法制造这些多级光学元件。通过实验对它们进行了表征，在350 - 1100 nm波长范围内的整体光学效率为70%，这与模拟预测结果非常吻合。最后，组装了两个原型设备：一个配备一对基于铜铟镓硒的光伏器件，另一个配备砷化镓和晶体硅光伏器件。在白光照明下，这些器件的输出峰值电功率分别提高了约42%和约22%。由于所提出的BDOE具有光学通用性和可制造性，所报道的光谱分离方法为低成本太阳能发电提供了一种新途径。
