Understanding and Removing Surface States Limiting Charge Transport in TiO2 Nanowire Arrays for Enhanced Optoelectronic Device Performance

Kai Zhu, Xia Sheng, Liping Chen, Tao Xu, Xinjian Feng

Research output: Contribution to journalArticlepeer-review

28 Scopus Citations

Abstract

Charge transport within electrode materials plays a key role in determining the optoelectronic device performance. Aligned single-crystal TiO2 nanowire arrays offer an ideal electron transport path and are expected to have higher electron mobility. Unfortunately, their transport is found not to be superior to that in nanoparticle films. Here we show that the low electron transport in rutile TiO2 nanowires is mainly caused by surface traps in relatively deep energy levels, which cannot be removed by conventional approaches, such as oxygen annealing treatment. Moreover, we demonstrate an effective wet-chemistry approach to minimize these trap states, leading to over 20-fold enhancement in electron diffusion coefficient and 62% improvement in solar cell performance. On the basis of our results, the potential of TiO2 NWs can be developed and well-utilized, which is significantly important for their practical applications.

Original languageAmerican English
Pages (from-to)1910-1913
Number of pages4
JournalChemical Science
Volume7
Issue number3
DOIs
StatePublished - 1 Mar 2016

Bibliographical note

Publisher Copyright:
© The Royal Society of Chemistry 2016.

NREL Publication Number

  • NREL/JA-5900-66161

Keywords

  • charge transport
  • electrode materials
  • TiO2 nanowires

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