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Title: Mesoscale trumps nanoscale: metallic mesoscale contact morphology for improved light trapping, optical absorption and grid conductance in silicon solar cells

Abstract

Here, we report on a computational study exploring the design of mesoscale metallic front contacts for solar cells. We investigated silver contact structures with circle, triangle and square cross-sections for various length scales and surface coverages. We found that for ‘nanoscale’ contacts with widths between 10 nm and 1000 nm, resonant coupling actually impairs light absorption in the semiconductor. Conversely, for ‘mesoscale’ contact widths > 1000 nm, the light interaction is determined by the geometric shadowing. We find that mesoscale silver contacts with triangular cross-section outperform other nanostructure morphologies in reducing shadow losses and yield contact transparency of >99% percent with sheet resistance <0.2 Ω/sq. Surprisingly, very densely spaced mesoscale silver triangular cross-section contacts can enhance the absorption of thin silicon/silver structures by up to 15% at a front contact coverage of 83%, due to light trapping by the front contact. Such structures can also maintain up to 100% absorption within the silicon, at a front contact coverage of 50%, relative to the same structure without metal.

Authors:
ORCiD logo; ORCiD logo
Publication Date:
Research Org.:
The Leland Stanford Junior Univ., Palo Alto, CA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1423923
Alternate Identifier(s):
OSTI ID: 1503310
Grant/Contract Number:  
EE0004946; EEC-1041895
Resource Type:
Published Article
Journal Name:
Optics Express
Additional Journal Information:
Journal Name: Optics Express Journal Volume: 26 Journal Issue: 6; Journal ID: ISSN 1094-4087
Publisher:
Optical Society of America
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; Solar energy; Micro-optics; Nanophotonics and photonic crystals

Citation Formats

Saive, Rebecca, and Atwater, Harry A. Mesoscale trumps nanoscale: metallic mesoscale contact morphology for improved light trapping, optical absorption and grid conductance in silicon solar cells. United States: N. p., 2018. Web. doi:10.1364/OE.26.00A275.
Saive, Rebecca, & Atwater, Harry A. Mesoscale trumps nanoscale: metallic mesoscale contact morphology for improved light trapping, optical absorption and grid conductance in silicon solar cells. United States. doi:10.1364/OE.26.00A275.
Saive, Rebecca, and Atwater, Harry A. Tue . "Mesoscale trumps nanoscale: metallic mesoscale contact morphology for improved light trapping, optical absorption and grid conductance in silicon solar cells". United States. doi:10.1364/OE.26.00A275.
@article{osti_1423923,
title = {Mesoscale trumps nanoscale: metallic mesoscale contact morphology for improved light trapping, optical absorption and grid conductance in silicon solar cells},
author = {Saive, Rebecca and Atwater, Harry A.},
abstractNote = {Here, we report on a computational study exploring the design of mesoscale metallic front contacts for solar cells. We investigated silver contact structures with circle, triangle and square cross-sections for various length scales and surface coverages. We found that for ‘nanoscale’ contacts with widths between 10 nm and 1000 nm, resonant coupling actually impairs light absorption in the semiconductor. Conversely, for ‘mesoscale’ contact widths > 1000 nm, the light interaction is determined by the geometric shadowing. We find that mesoscale silver contacts with triangular cross-section outperform other nanostructure morphologies in reducing shadow losses and yield contact transparency of >99% percent with sheet resistance <0.2 Ω/sq. Surprisingly, very densely spaced mesoscale silver triangular cross-section contacts can enhance the absorption of thin silicon/silver structures by up to 15% at a front contact coverage of 83%, due to light trapping by the front contact. Such structures can also maintain up to 100% absorption within the silicon, at a front contact coverage of 50%, relative to the same structure without metal.},
doi = {10.1364/OE.26.00A275},
journal = {Optics Express},
number = 6,
volume = 26,
place = {United States},
year = {2018},
month = {3}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1364/OE.26.00A275

Citation Metrics:
Cited by: 6 works
Citation information provided by
Web of Science

Figures / Tables:

Fig. 1 Fig. 1: Schematic of the interaction of light with wave vector and metal structures of width w in the a) nanoscale (w<<λ), b) mesoscale (w ≥ λ) and c) macroscale (w>>λ).

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.