title: Highly stable tandem solar cell monolithically integrating dye-sensitized and CIGS solar cells.
abstract: A highly stable monolithic tandem solar cell was developed by combining the heterogeneous photovoltaic technologies of dye-sensitized solar cell (DSSC) and solution-processed CuInxGa1-xSeyS1-y (CIGS) thin film solar cells. The durability of the tandem cell was dramatically enhanced by replacing the redox couple from to [Co(bpy)3](2+) /[Co(bpy)3](3+)), accompanied by a well-matched counter electrode (
  
  
  
  PSS) and sensitizer (Y123). A 1000 h durability test of the DSSC/CIGS tandem solar cell in ambient conditions resulted in only a 5% decrease in solar cell efficiency. Based on electrochemical impedance spectroscopy and photoelectrochemical cell measurement, the enhanced stability of the tandem cell is attributed to minimal corrosion by the cobalt-based polypyridine complex redox couple.
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.|Department of Chemistry, College of Science, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
authors.forename: Sang Youn
authors.initials: SY
authors.lastname: Chae
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.|Department of Materials Science and Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.
authors.forename: Oh-Shim
authors.initials: OS
authors.lastname: Joo
authors.affiliation: Department of Materials Chemistry and Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 143-701, Republic of Korea.
authors.forename: Yongseok
authors.initials: Y
authors.lastname: Jun
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.|Green School, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea.
authors.forename: Byoung Koun
authors.initials: BK
authors.lastname: Min
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology, Hwarang-ro 14-gil 5, Seongbuk-gu, Seoul, 02792, Republic of Korea.
authors.forename: Yun Jeong
authors.initials: YJ
authors.lastname: Hwang