Record high efficiency single-walled carbon nanotube/silicon p - N junction solar cells

Yeonwoong Jung, Xiaokai Li, Nitin K. Rajan, André D. Taylor, Mark A. Reed

Research output: Contribution to journalArticle

Abstract

Carrier transport characteristics in high-efficiency single-walled carbon nanotubes (SWNTs)/silicon (Si) hybrid solar cells are presented. The solar cells were fabricated by depositing intrinsic p-type SWNT thin-films on n-type Si wafers without involving any high-temperature process for p-n junction formation. The optimized cells showed a device ideality factor close to unity and a record-high power-conversion-efficiency of >11%. By investigating the dark forward current density characteristics with varying temperature, we have identified that the temperature-dependent current rectification originates from the thermally activated band-to-band transition of carriers in Si, and the role of the SWNT thin films is to establish a built-in potential for carrier separation/collection. We have also established that the dominant carrier transport mechanism is diffusion, with minimal interface recombination. This is further supported by the observation of a long minority carrier lifetime of ∼34 μs, determined by the transient recovery method. This study suggests that these hybrid solar cells operate in the same manner as single crystalline p-n homojunction Si solar cells.

Original languageEnglish (US)
Pages (from-to)95-99
Number of pages5
JournalNano Letters
Volume13
Issue number1
DOIs
StatePublished - Jan 9 2013

Keywords

  • CNT/Si solar cell
  • high efficiency
  • hybrid solar cell
  • ideality factor
  • photovoltaics
  • temperature dependency

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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