Improving performance and lifetime of small-molecule organic photovoltaic devices by using bathocuproine-fullerene cathodic layer

Shun Wei Liu, Chih Chien Lee, Wei Cheng Su, Chih Hsien Yuan, Yi Sheng Shu, Wen Chang Chang, Jhih Yan Guo, Chien Feng Chiu, Ya Ze Li, Tsung Hao Su, Kuan Ting Chen, Po Chien Chang, Tzu Hung Yeh, Yu Hsuan Liu

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

In this study, we compared the use of neat bathocuproine (BCP) and BCP:C60 mixed buffer layers in chloroboron subphthalocyanine (SubPc)/C60 bilayer organic photovoltaic (OPV) devices and analyzed their influence on device performance. Replacing the conventional BCP with BCP:C60 enabled manipulating the optical field distribution for optimizing the optical properties of the devices. Estimation of the interfacial barrier indicated that the insertion of the BCP:C60 between the C60 and electrode can effectively reduce the barrier for electrons and enhance electron collection at the electrode. Temperature-dependent measurements of the OPV devices performed to calculate the barrier height at the SubPc/C60 interface suggested that band bending was larger when the BCP:C60 buffer layer was used, reflecting increased exciton dissociation efficiency. In addition, the device lifetime was considerably improved when the BCP:C60 buffer layer was used. The device performance was stabilized after the photodegradation of the active layers, thereby increasing the device lifetime compared with the use of the neat BCP buffer layer. Atomic force microscopy images showed that the neat BCP was easily crystallized and could degrade the cathodic interface, whereas the blend of C60 and BCP suppressed the crystallization of BCP. Therefore, the optimal buffer layer improved both the device performance and the device lifetime.

Original languageEnglish
Pages (from-to)9262-9273
Number of pages12
JournalACS Applied Materials and Interfaces
Volume7
Issue number17
DOIs
Publication statusPublished - May 6 2015
Externally publishedYes

Keywords

  • Cathodic buffer layer
  • Lifetime
  • Morphology
  • Optical manipulation
  • Power conversion efficiency
  • small-molecule organic photovoltaic

ASJC Scopus subject areas

  • Materials Science(all)

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  • Cite this

    Liu, S. W., Lee, C. C., Su, W. C., Yuan, C. H., Shu, Y. S., Chang, W. C., Guo, J. Y., Chiu, C. F., Li, Y. Z., Su, T. H., Chen, K. T., Chang, P. C., Yeh, T. H., & Liu, Y. H. (2015). Improving performance and lifetime of small-molecule organic photovoltaic devices by using bathocuproine-fullerene cathodic layer. ACS Applied Materials and Interfaces, 7(17), 9262-9273. https://doi.org/10.1021/acsami.5b01888