Copper Outdiffusion from Copper-Plated Solar Cell Contacts during Damp Heat Exposure

Joseph Karas, Benjamin Phua, Alvin Mo, Nafis Iqbal, Kristopher Davis, Stuart Bowden, Alison Lennon, André Augusto

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Plated copper (Cu) contacts for silicon (Si) solar cells are an attractive alternative material to conventional screenprinted silver, but there are unresolved questions on the long-term integrity of plated contact structures. In this work, we perform characterization on plated Cu contacts from encapsulated cells that were degraded during extended exposure to damp heat (DH) stress. First, using energy-dispersive X-ray spectroscopy, we find evidence of Cu outdiffusion upward through capping layers made of both tin and silver applied with light-induced plating, resulting in a layer of Cu on the outer contact surface. We hypothesize that if Cu is mobile in the module, it may eventually find some route by which to enter the Si cells where it can degrade performance. Subsequently, in several types of Cu-plated, DH-degraded cells, secondary ion mass spectrometry detects elevated levels of Cu at the Si surface and in the Si cell bulk, which suggests that Cu can indeed migrate from contacts into Si over the course of DH stress.

Original languageEnglish (US)
Pages (from-to)12149-12155
Number of pages7
JournalACS Applied Materials and Interfaces
Issue number10
StatePublished - Mar 16 2022


  • copper
  • damp heat
  • diffusion
  • plating
  • silver
  • solar cell
  • tin

ASJC Scopus subject areas

  • General Materials Science


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