Title: Demonstration of a $\text{G}\text{aS}\text{b}/\mathrm{Ga}\text{A}\text{s}$ Quantum Dot Intermediate Band Solar Cell Operating at Maximum Power Point

Abstract

Intermediate band solar cells (IBSCs) promise high efficiencies while maintaining a low device structural complexity. A high efficiency can be obtained by harvesting below-band-gap photons, thus increasing the current, while at the same time preserving a high voltage. Here, we provide experimental proof that below-band-gap photons can be used to produce nonzero electrical work in an IBSC without compromising the voltage. For this, we manufacture a GaSb / GaAs quantum-dot IBSC. We use light biasing and make our cell operate at the maximum power point at 9 K. We measure the photocurrent response to absorption of photons with an energy of less than 1.15 eV while the cell is operating at 1.15 V. We also show that this result implies the existence of three quasi-Fermi levels linked to the three electronic bands in our device, as demanded by the IBSC theory to preserve the output voltage of the cell.

Authors:

Ramiro, I. ;

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• Search DOE PAGES for ORCID "0000-0002-9663-4002"
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Villa, J. ;

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• Search DOE PAGES for ORCID "0000-0002-3009-4701"
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Hwang, J. ;

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• Search DOE PAGES for ORCID "0000-0002-9780-1538"
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Martin, A. J.; Millunchick, J.; Phillips, J. ;

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• Search DOE PAGES for ORCID "0000-0003-2642-3717"
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Martí, A.

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• Search DOE PAGES for ORCID "0000-0002-8841-7091"
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Publication Date:

2020-12-09

Research Org.:

Univ. of Michigan, Ann Arbor, MI (United States)

Sponsoring Org.:

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

OSTI Identifier:

1734941

Alternate Identifier(s):

OSTI ID: 1850623

Grant/Contract Number:  

SC0000957

Resource Type:

Published Article

Journal Name:

Physical Review Letters

Additional Journal Information:

Journal Name: Physical Review Letters Journal Volume: 125 Journal Issue: 24; Journal ID: ISSN 0031-9007

Publisher:

American Physical Society

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Physics; Optoelectronics; Optical and microwave phenomena; Photovoltaic effect; Photoconductivity; Photovoltaic absorbers; Functional materials; Energy materials; Quantum dots; 0-dimensional systems