Design for strong absorption in a nanowire array tandem solar cell

Yang Chen, Mats Erik Pistol, Nicklas Anttu*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

20 Citations (Scopus)

Abstract

Semiconductor nanowires are a promising candidate for next-generation solar cells. However, the optical response of nanowires is, due to diffraction effects, complicated to optimize. Here, we optimize through optical modeling the absorption in a dual-junction nanowire-array solar cell in terms of the Shockley-Quessier detailed balance efficiency limit. We identify efficiency maxima that originate from resonant absorption of photons through the HE11 and the HE12 waveguide modes in the top cell. An efficiency limit above 40% is reached in the band gap optimized Al0.10Ga0.90As/In0.34Ga0.66 As system when we allow for different diameter for the top and the bottom nanowire subcell. However, for experiments, equal diameter for the top and the bottom cell might be easier to realize. In this case, we find in our modeling a modest 1-2% drop in the efficiency limit. In the Ga0.51In0.49 P/InP system, an efficiency limit of = 37.3% could be reached. These efficiencies, which include reflection losses and sub-optimal absorption, are well above the 31.0% limit of a perfectly-absorbing, idealized single-junction bulk cell, and close to the 42.0% limit of the idealized dual-junction bulk cell. Our results offer guidance in the choice of materials and dimensions for nanowires with potential for high efficiency tandem solar cells.

Original languageEnglish
Article number32349
JournalScientific Reports
Volume6
DOIs
Publication statusPublished - 30 Aug 2016
MoE publication typeA1 Journal article-refereed

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