Title: Optimization of Photon and Electron Collection Efficiencies in Silicon Solar Microcells for Use in Concentration-Based Photovoltaic Systems

Abstract

Abstract Ultrathin silicon solar microcells (μ‐cells) afford a means to reduce semiconductor material consumption and can be integrated with concentration optics to improve their power density. A μ‐cell design is described that optimizes electron and photon collection with enhanced efficiency for solar concentration applications. An interdigitated back contact (IBC) design improves carrier collection partially due to larger contact coverage while further enabling optimization of the μ‐cell front surface. To do so, a silicon nitride antireflection thin film coating is utilized to enhance photon absorption and improve surface passivation. Performance of IBC μ‐cells is compared to an optimized top contact design and improves μ‐cell conversion efficiencies from 9.9 to 13.7%. Improvements at 1 Sun are amplified under concentration and increase power densities at 20 Suns to 346 from 192 mW cm ⁻² due to minimized series resistance. Benefits afforded by IBC μ‐cells are exemplified following their integration into a dual concentrator system, affording photon collection capacities for direct and diffuse irradiance. A traditional lens concentrates direct light while a luminescent solar concentrator (LSC) collects diffuse photons otherwise not utilized by passive optics. Addition of the LSC increases maximum power densities on clear and cloudy days, providing concentration for the latter andmore » further increasing the power density.« less

Authors:

Yoder, Mikayla A. ^[1]; Yao, Yuan ^[1]; He, Junwen ^[1]; Nuzzo, Ralph G. ^[1]

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+ Show Author Affiliations

1. Univ. of Illinois at Urbana-Champaign, IL (United States). Fredrick Seitz Materials Research Laboratory, Dept. of Chemistry

Publication Date:

Fri Sep 29 00:00:00 EDT 2017

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Light-Material Interactions in Energy Conversion (LMI)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1470395

Alternate Identifier(s):

OSTI ID: 1395603

Grant/Contract Number:  

SC0001293; DE‐SC0001293; 67N‐1087758

Resource Type:

Accepted Manuscript

Journal Name:

Advanced Materials Technologies

Additional Journal Information:

Journal Volume: 2; Journal Issue: 11; Related Information: LMI partners with California Institute of Technology (lead); Harvard University; University of Illinois, Urbana-Champaign; Lawrence Berkeley National Laboratory; Journal ID: ISSN 2365-709X

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

14 SOLAR ENERGY; 36 MATERIALS SCIENCE; 42 ENGINEERING; solar (photovoltaic); solid state lighting; phonons; thermal conductivity; electrodes - solar; materials and chemistry by design; optics; synthesis (novel materials); synthesis (self-assembly)