Understanding What Limits the Voltage of Polycrystalline CdSeTe Solar Cells

Arthur Onno, Carey Reich, Siming Li, Adam Danielson, William Weigand, Alexandra Bothwell, Sachit Grover, Jeff Bailey, Gang Xiong, Darius Kuciauskas, Walajabad Sampath, Zachary Holman

Research output: Contribution to journalArticlepeer-review

35 Scopus Citations

Abstract

The origin of voltage deficits in polycrystalline cadmium selenide telluride (CdSeTe) solar cells is unclear. Here, we present a comprehensive voltage loss analysis performed on state-of-the-art CdSeTe devices—fabricated at Colorado State University and First Solar—using photoluminescence techniques, including external radiative efficiency (ERE) measurements. More specifically, we report the thermodynamic voltage limit Voc,ideal, internal voltage iVoc and external voltage Voc of partially and fully finished cells fabricated with different dopant species, dopant concentrations and back contacts. Arsenic-doped aluminium-oxide-passivated cells made at Colorado State University present remarkably high ERE (>1%)—translating into iVoc above 970 mV—but suffer from poor back-contact selectivity. On the other hand, arsenic-doped devices from First Solar present almost perfect carrier selectivity (Voc = iVoc), leading to Voc above 840 mV, and are limited by recombination in various parts of the device. Thus, development of contact structures that are both passivating and selective in combination with highly luminescent absorbers is key to reducing voltage losses.

Original languageAmerican English
Pages (from-to)400-408
Number of pages9
JournalNature Energy
Volume7
Issue number5
DOIs
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Limited.

NREL Publication Number

  • NREL/JA-5900-81287

Keywords

  • CdSeTe devices
  • CdTe
  • external radiative efficiency
  • photoluminescence
  • thermodynamic voltage limit
  • voltage loss analysis

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