Investigation of Some Transparent Metal Oxides as Damp Heat Protective Coating for CIGS Solar Cells: Preprint

Research output: Contribution to conferencePaper


We investigated the protective effectiveness of some transparent metal oxides (TMO) on CIGS solar cell coupons against damp heat (DH) exposure at 85oC and 85% relative humidity (RH). Sputter-deposited bilayer ZnO (BZO) with up to 0.5-um Al-doped ZnO (AZO) layer and 0.2-um bilayer InZnO were used as 'inherent' part of device structure on CdS/CIGS/Mo/SLG. Sputter-deposited 0.2-um ZnSnO and atomiclayer deposited (ALD) 0.1-um Al2O3 were used as overcoat on typical BZO/CdS/CIGS/Mo/SLG solar cells. The results were all negative -- all TMO-coated CIGS cells exhibited substantial degradation in DH. Combining the optical photographs, PL and EL imaging, SEM surface micro-morphology, coupled with XRD, I-V and QE measurements, the causes of the device degradations are attributed to hydrolyticcorrosion, flaking, micro-cracking, and delamination induced by the DH moisture. Mechanical stress and decrease in crystallinity (grain size effect) could be additional degrading factors for thicker AZO grown on CdS/CIGS.
Original languageAmerican English
Number of pages17
StatePublished - 2012
EventSPIE Optics + Photonics - San Diego, California
Duration: 12 Aug 201216 Aug 2012


ConferenceSPIE Optics + Photonics
CitySan Diego, California

NREL Publication Number

  • NREL/CP-5200-54188


  • Al-doped ZnO
  • ALD Al2O3
  • amorphous InZnO
  • CIGS solar cells
  • damp heat stability
  • transparent metal oxide
  • ZnSnO


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