Numerical analysis of bifacial silicon-based tandem devices: Shifts in the optimum top-cell bandgap with varying albedo

Arthur Onno, Zachary Holman

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

According to detailed-balance analysis, Si-based tandem devices require a top-cell bandgap of 1.70-1.75 eV to be current-matched and deliver high efficiencies in a two-terminal configuration. However, no such top cell - able to deliver the required Jsc of approximately 20 mA.cm-2 along with a Voc>1.2 V - has been demonstrated so far. In this work, we present an alternative pathway, using a bifacial c-Si device as the bottom cell. Thanks to the current boost from absorption through the bifacial c-Si cell's rear surface, a lower bandgap is necessary for the top cell. In particular, we show that, with an albedo in the 20-45 % range, the optimal top-cell bandgap lies in the 1.4-1.55 eV range, corresponding to common high-efficiency absorber materials, including GaAs, CdTe, and perovskites. However, when considering more realistic systems where shading of the area under the modules occurs, the optimal top-cell bandgap shifts back to higher values. Moreover, this optimum varies throughout the day, as the ratio between direct and diffuse light as well as their respective spectral components evolve.

Original languageEnglish (US)
Title of host publication2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages229-232
Number of pages4
ISBN (Electronic)9781538685297
DOIs
StatePublished - Nov 26 2018
Event7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - Waikoloa Village, United States
Duration: Jun 10 2018Jun 15 2018

Other

Other7th IEEE World Conference on Photovoltaic Energy Conversion, WCPEC 2018
CountryUnited States
CityWaikoloa Village
Period6/10/186/15/18

Keywords

  • albedo
  • bifacial solar cell
  • current-matching
  • silicon
  • simulation
  • tandem

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Renewable Energy, Sustainability and the Environment
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials

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    Onno, A., & Holman, Z. (2018). Numerical analysis of bifacial silicon-based tandem devices: Shifts in the optimum top-cell bandgap with varying albedo. In 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion, WCPEC 2018 - A Joint Conference of 45th IEEE PVSC, 28th PVSEC and 34th EU PVSEC (pp. 229-232). [8547679] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/PVSC.2018.8547679