Achievement of 17.9% efficiency in 30 × 30 cm2 Cu(In,Ga)(Se,S)2 solar cell sub-module by sulfurization after selenization with Cd-free buffer

Junggyu Nam, Yoonmook Kang, Dongho Lee, Jungyup Yang, Young Su Kim, Chan B. Mo, Sungchan Park, Dongseop Kim

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


We have achieved 17.9% efficiency in a 30 × 30 cm2 Cu(In,Ga)(Se,S)2 solar cell sub-module prepared by selenization and sulfurization processes with a Cd-free buffer. The development of an absorber layer, transparent conducting oxide window layer, and module design was the key focus. This permitted 1.8% higher efficiency than our last experimental result. The quantity and the injection time of the sodium were controlled, resulting in higher open circuit voltage (Voc) and short circuit current (Jsc). In order to increase Jsc, we changed the thickness of the window layer. Boron-doped zinc oxide was optimized for higher transmittance without reducing the fill factor. The uniformity of each layer was improved, and patterns were optimized for each module. Therefore, Voc, Jsc, and FF could be theoretically improved on the reported results of, respectively, 20 mV, 2 mA/cm2, and 1.4%. The module's efficiency was measured at the Korea Test Laboratory to compare with the data obtained in-house. Various analyses were performed, including secondary ion mass spectroscopy, photoluminescence, quantum efficiency, solar simulator, and UV-vis spectrometry, to measure the cell's depth profile, carrier lifetime, external quantum efficiency, module efficiency, and transmittance, respectively.

Original languageEnglish
Pages (from-to)175-182
Number of pages8
JournalProgress in Photovoltaics: Research and Applications
Issue number2
Publication statusPublished - 2016 Feb 1


  • Band profile
  • CIGS solar cell
  • Mo back contact
  • Na diffusion

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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