Excitonic Effects in Emerging Photovoltaic Materials: A Case Study in Cu_2O

Omelchenko, Stefan T. and Tolstova, Yulia and Atwater, Harry A. and Lewis, Nathan S. (2017) Excitonic Effects in Emerging Photovoltaic Materials: A Case Study in Cu_2O. ACS Energy Letters, 2 (2). pp. 431-437. ISSN 2380-8195. doi:10.1021/acsenergylett.6b00704. https://resolver.caltech.edu/CaltechAUTHORS:20170126-105722527

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Abstract

Excitonic effects account for a fundamental photoconversion and charge transport mechanism in Cu_2O; hence, the universally adopted “free carrier” model substantially underestimates the photovoltaic efficiency for such devices. The quasi-equilibrium branching ratio between excitons and free carriers in Cu_2O indicates that up to 28% of photogenerated carriers during photovoltaic operation are excitons. These large exciton densities were directly observed in photoluminescence and spectral response measurements. The results of a device physics simulation using a model that includes excitonic effects agree well with experimentally measured current–voltage characteristics of Cu_2O-based photovoltaics. In the case of Cu_2O, the free carrier model underestimates the efficiency of a Cu_2O solar cell by as much as 1.9 absolute percent at room temperature.

Item Type:

Article

Related URLs:

URL	URL Type	Description
http://dx.doi.org/10.1021/acsenergylett.6b00704	DOI	Article
http://pubs.acs.org/doi/abs/10.1021/acsenergylett.6b00704	Publisher	Article
http://pubs.acs.org/doi/suppl/10.1021/acsenergylett.6b00704	Publisher	Supporting Information

ORCID:

Author	ORCID
Omelchenko, Stefan T.	0000-0003-1104-9291
Atwater, Harry A.	0000-0001-9435-0201
Lewis, Nathan S.	0000-0001-5245-0538

Additional Information:

© 2017 American Chemical Society. Received: December 19, 2016; Accepted: January 19, 2017; Published: January 19, 2017. This material is based upon work performed by the Joint Center for Artificial Photosynthesis, a DOE Energy Innovation Hub, supported through the Office of Science of the U.S. Department of Energy under Award Number DE-SC0004993. Y.T. and H.A.A. are supported by the Dow Chemical Company under the earth-abundant semiconductor project. S.T.O. thanks S. Yalamanchili, K. Sun, and A. Carim for helpful discussions. The authors declare no competing financial interest.

Group:

JCAP, Kavli Nanoscience Institute

Funders:

Funding Agency	Grant Number
Department of Energy (DOE)	DE-SC0004993
Dow Chemical Company	UNSPECIFIED

Issue or Number:

DOI:

10.1021/acsenergylett.6b00704

Record Number:

CaltechAUTHORS:20170126-105722527

Persistent URL:

https://resolver.caltech.edu/CaltechAUTHORS:20170126-105722527

Official Citation:

Excitonic Effects in Emerging Photovoltaic Materials: A Case Study in Cu2O Stefan T. Omelchenko, Yulia Tolstova, Harry A. Atwater, and Nathan S. Lewis ACS Energy Letters 2017 2 (2), 431-437 DOI: 10.1021/acsenergylett.6b00704

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No commercial reproduction, distribution, display or performance rights in this work are provided.

ID Code:

73753

Collection:

CaltechAUTHORS

Deposited By:

Tony Diaz

Deposited On:

26 Jan 2017 19:57

Last Modified:

11 Nov 2021 05:21

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