Effect of Er3+ and Yb3+ co-doping on the performance of a ZnO-based DSSC

Ermias Libnedengel Tsege, Hong Ha Thi Vu, Timur Sh Atabaev, Hyung Kook Kim, Yoon Hwae Hwang

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Zinc-oxide (ZnO) nanoparticles (NPs) co-doped with different concentrations of rare-earth ions of erbium and ytterbium, (ZnO: Er3+, Yb3+) were synthesized for applications to ZnO-based dye sensitized solar cells (DSSC). The composite NPs used for the photoelectrode (PE) were synthesized using a simple co-precipitation technique. X-ray diffraction and scanning electron microscopy measurements on the prepared samples revealed a single phase wurzite ZnO powder with approximate sizes in the range from 15 to 20 nm. Photoluminescence (PL) measurements confirmed that the synthesized composite NPs had a good up-conversion (UPC) property. The prepared powders were directly used to make PEs for DSSCs. The photovoltaic efficiency of the DSSCs was enhanced compared to that of pure ZnO-based DSSCs. Particularly, the PE made up of ZnO: Er3+, Yb3+ NPs with 4 wt% of Er3+ and Yb3+ generates a short-circuit current density (Jsc) of 4.794 mA·cm −2 and an open circuit voltage (Voc) of 0.602 V with an efficiency (η) of 1.58%. The result indicates a 48.4% Jsc improvement compared to a pure ZnO PE-based DSSC. The photocurrent improvement is due to an increase in the light-harvesting capacity of the PEs attained through the UPC property of ZnO: Er3+, Yb3+ NPs. As confirmed by PL and electrochemical impedance spectra (EIS), the use of ZnO: Er3+,Yb3+ NPs as PEs for DSSCs enhances charge concentration and transport as a result of n-type doping. However, all ZnO: Er3+, Yb3+ NP based PEs exhibited a lower Voc as a result of a down shift in the Fermi energy, which affects the overall efficiency of the cell.

Original languageEnglish
Pages (from-to)1381-1389
Number of pages9
JournalJournal of the Korean Physical Society
Volume68
Issue number12
DOIs
Publication statusPublished - Jun 1 2016
Externally publishedYes

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Keywords

  • Co-precipitation
  • Defects
  • Nanoparticles
  • Photoelectrode
  • Rare-earth
  • Up-conversion

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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