Excitonic Effects in Emerging Photovoltaic Materials: A Case Study in Cu2O

Stefan T. Omelchenko, Yulia Tolstova, Harry A. Atwater, Nathan S. Lewis

Research output: Contribution to journalReview article

7 Citations (Scopus)

Abstract

Excitonic effects account for a fundamental photoconversion and charge transport mechanism in Cu2O; 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 Cu2O 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 Cu2O-based photovoltaics. In the case of Cu2O, the free carrier model underestimates the efficiency of a Cu2O solar cell by as much as 1.9 absolute percent at room temperature.

Original languageEnglish
Pages (from-to)431-437
Number of pages7
JournalACS Energy Letters
Volume2
Issue number2
DOIs
Publication statusPublished - Feb 10 2017

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ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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