Cocktails of paste coatings for performance enhancement of CuInGaS 2 thin-film solar cells

Hee Sang An, Yunae Cho, Se Jin Park, Hyo Sang Jeon, Yun Jeong Hwang, Dong Wook Kim, Byoung Koun Min

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


To fabricate low-cost and printable wide-bandgap CuInxGa 1-xS2 (CIGS) thin-film solar cells, a method based on a precursor solution was developed. In particular, under this method, multiple coatings with two pastes with different properties (e.g., viscosity) because of the different binder materials added were applied. Paste A could form a thin, dense layer enabling a high-efficiency solar cell but required several coating and drying cycles for the desired film thickness. On the other hand, paste B could easily form one-micrometer-thick films by means of a one-time spin-coating process but the porous microstructure limited the solar cell performance. Three different configurations of the CIGS films (A + B, B + A, and A + B + A) were realized by multiple coatings with the two pastes to find the optimal stacking configuration for a combination of the advantages of each paste. Solar cell devices using these films showed a notable difference in their photovoltaic characteristics. The bottom dense layer increased the minority carrier diffusion length and enhanced the short-circuit current. The top dense layer could suppress interface recombination but exhibited a low optical absorption, thereby decreasing the photocurrent. As a result, the A + B configuration could be suggested as a desirable simple stacking structure. The solar cell with A + B coating showed a highly improved efficiency (4.66%) compared to the cell with a film prepared by paste B only (2.90%), achieved by simple insertion of a single thin (200 nm), dense layer between the Mo back contact and a thick porous CIGS layer.

Original languageEnglish
Pages (from-to)888-893
Number of pages6
JournalACS Applied Materials and Interfaces
Issue number2
StatePublished - 22 Jan 2014


  • chalcopyrite
  • paste coating
  • solar cells
  • solution process
  • sulfurization


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