Improvement of Charge Collection and Performance Reproducibility in Inverted Organic Solar Cells by Suppression of ZnO Subgap States

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

30 Scopus Citations
View graph of relations

Author(s)

  • Bo Wu
  • Zhenghui Wu
  • Qingyi Yang
  • Furong Zhu
  • Tsz-Wai Ng
  • Sin-Hang Cheung
  • Shu-Kong So

Detail(s)

Original languageEnglish
Pages (from-to)14717-14724
Journal / PublicationACS Applied Materials and Interfaces
Volume8
Issue number23
Publication statusPublished - 15 Jun 2016

Abstract

Organic solar cells (OSCs) with inverted structure usually exhibit higher power conversion efficiency (PCE) and are more stable than corresponding devices with regular configuration. Indium tin oxide (ITO) surface is often modified with solution-processed low work function metal oxides, such as ZnO, serving as the transparent cathode. However, the defect-induced subgap states in the ZnO interlayer hamper the efficient charge collection and the performance reproducibility of the OSCs. In this work, we demonstrate that suppression of the ZnO subgap states by modification of its surface with an ultrathin Al layer significantly improves the charge extraction and performance reproducibility, achieving PCE of 8.0%, which is ∼15% higher than that of a structurally identical control cell made with a pristine ZnO interlayer. Light intensity-dependent current density-voltage characteristic, photothermal deflection spectroscopy, and X-ray photoelectron spectroscopy measurements point out the enhancement of charge collection efficiency at the organic/cathode interface, due to the suppression of the subgap states in the ZnO interlayer.

Research Area(s)

  • charge collection, organic solar cells, organic/cathode interface, oxide interlayer, subgap states

Citation Format(s)

Improvement of Charge Collection and Performance Reproducibility in Inverted Organic Solar Cells by Suppression of ZnO Subgap States. / Wu, Bo; Wu, Zhenghui; Yang, Qingyi; Zhu, Furong; Ng, Tsz-Wai; Lee, Chun-Sing; Cheung, Sin-Hang; So, Shu-Kong.

In: ACS Applied Materials and Interfaces, Vol. 8, No. 23, 15.06.2016, p. 14717-14724.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review