Increased Photovoltaic Power Output via Diffractive Spectrum Separation

Ganghun Kim, Jose A. Dominguez-Caballero, Howard Lee, Daniel J. Friedman, Rajesh Menon

Research output: Contribution to journalArticlepeer-review

62 Scopus Citations

Abstract

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.

Original languageAmerican English
Article numberArticle No. 123901
Number of pages5
JournalPhysical Review Letters
Volume110
Issue number12
DOIs
StatePublished - 21 Mar 2013

NREL Publication Number

  • NREL/JA-5200-58576

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