Exceptionally omnidirectional broadband light harvesting scheme for multi-junction concentrator solar cells achieved via ZnO nanoneedles

Abstract
GaInP/GaAs/Ge triple-junction concentrator solar cells with significant efficiency enhancement were demonstrated with antireflective ZnO nanoneedles. The novel nanostructure was attained with a Zn(NO3)2-based solution containing vitamin C. Under one sun AM 1.5G solar spectrum, conversion efficiency of the triple-junction device was improved by 23.7% via broadband improvement in short-circuit currents of 3 sub-cells after the coverage by the nanoneedles with a graded refractive index profile. The efficiency enhancement further went up to 45.8% at 100 suns. The performance boost through the nanoneedles also became increasingly pronounced in the conditions of high incident angles and the cloudy weather, e.g. 220.0% of efficiency enhancement was observed at the incident angle of 60°. These results were attributed to the exceptional broadband omnidirectionality of the antireflective nanoneedles.

Citation
Yeh L-K, Tian W-C, Lai K-Y, He J-H (2016) Exceptionally omnidirectional broadband light harvesting scheme for multi-junction concentrator solar cells achieved via ZnO nanoneedles. Scientific Reports 6: 39134. Available: http://dx.doi.org/10.1038/srep39134.

Acknowledgements
This work was supported by the baseline fund of King Abdullah University of Science & Technology (KAUST), and the Ministry of Science and Technology in Taiwan (Grant MOST105-3113-E-008-008-CC2 and MOST 105-2221-E-008-064).

Publisher
Springer Nature

Journal
Scientific Reports

DOI
10.1038/srep39134

Additional Links
http://www.nature.com/articles/srep39134

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