Journal of Sol-Gel Science and Technology

, Volume 86, Issue 2, pp 266–273 | Cite as

Impact of thiourea concentration on the properties of sol–gel derived Zn(O,S) thin films and Cu(In,Ga)Se2 solar cells

  • Wenwen Wu
  • Honglie Shen
  • Jieyi Chen
  • Huirong Shang
  • Jinze Li
  • Wangyang Yang
  • Yufang Li
Original Paper: Devices based on sol-gel or hybrid materials


A novel approach based on sol–gel spin coating method to deposit Zn(O,S) thin film using thiourea(TU) as a sulfur source replacing CdS as buffer layer was developed and the influence of TU concentration on the properties of Zn(O,S) thin films and Cu(In,Ga)Se2(CIGS) solar cells were investigated in this paper. It was found by X-ray diffraction and X-ray photoelectron spectroscopy that sol–gel derived Zn(O,S) thin films were amorphous and composed of ZnS, ZnO as well as Zn(OH)2. The variation of the optical band gap as a function of the S/(S+O) ratio was determined by energy-dispersive spectroscopy and UV-VIS-NIR. The results indicated that the minimum value for band gap of approximate 3.72 eV was obtained when the S/(S+O) = 0.44. Efficiency of up to 7.28% was achieved for a CIGS solar cell with Zn(O,S) buffer layer from 0.2M TU, which was attributed to the optimized conduction band offset (CBO) of +0.45 eV at the CIGS/Zn(O,S) interface.

Zn(O,S) thin films prepared in sol–gel route was used to replace traditional CdS buffer layer deposited by chemical bath deposition method in Cu(In,Ga)Se2 solar cells. The best efficiency was achieved for CIGS/Zn(O,S)/i-ZnO/ITO heterostructure solar cell with S/(S+O) = 0.18, which was attributed to the optimized conduction band offset (CBO) of +0.45 eV at the CIGS/Zn(O,S) interface.


Zn(O,S) Sol–gel method TU concentration CIGS solar cells CBO 



This study was funded by the National Nature Science Foundation of China (61774084), a project supported by the special fund of Jiangsu Province for the transformation of scientific and technological achievements (BA2015121) and Joint Frontier Research Project of Jiangsu Province (BY2016003-09), a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions and Opening Project of State Key Laboratory of Advanced Technology for Float Glass.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Wenwen Wu
    • 1
  • Honglie Shen
    • 1
    • 2
  • Jieyi Chen
    • 1
  • Huirong Shang
    • 1
  • Jinze Li
    • 1
  • Wangyang Yang
    • 1
  • Yufang Li
    • 1
    • 3
  1. 1.College of Materials Science & Technology, Jiangsu Key Laboratory of Materials and Technology for Energy ConversionNanjing University of Aeronautics & AstronauticsNanjingPeople’s Republic of China
  2. 2.Jiangsu Collaborative Innovation Center of Photovoltaic Science and EngineeringChangzhou UniversityChangzhouPeople’s Republic of China
  3. 3.State Key Laboratory of Advanced Technology for Float GlassBengbu Design & Research Institute for Glass IndustryBengbuPeople’s Republic of China

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