Thin-film encapsulation of polymer-based bulk-heterojunction photovoltaic cells by atomic layer deposition

Chih Yu Chang, Chun Ting Chou, Yun Jun Lee, Miin Jang Chen, Feng Yu Tsai

Research output: Contribution to journalArticlepeer-review

69 Citations (Scopus)


This study demonstrated thin-film encapsulation of bulk-heterojunction polymer photovoltaic cells, utilizing a process based on atomic layer deposition (ALD) that both prevented degradation caused by ambient gases and served as an annealing step that increased the initial efficiency of the cells. With the ALD temperature set at 140 °C and the total deposition time set at 1 h, the photovoltaic cells, based on blended poly-3-hexylthiophene (P3HT) and [6,6]-phenyl C61 butyric acid methylester (PCBM), were optimally annealed during encapsulation, achieving a power conversion efficiency (PCE) of 3.66%. Encapsulating the cells with a 26 nm Al2O3/HfO2 nanolaminated film overcoated with an epoxy resin protection layer enabled the cells to obtain an in-air degradation rate that was similar to cells that were stored in nominally O2/H2O-free atmosphere. The nanolaminated structure of the encapsulation film resolved the issue of hydrolysis-induced aging observed with Al2O3 films, owing to the hydrophobicity of the HfO2 layers. Additionally, extended exposure of the ALD precursors during the ALD process significantly improved the coverage of the ALD films over the P3HT/PCBM active layer at the perimeter of the cells.

Original languageEnglish
Pages (from-to)1300-1306
Number of pages7
JournalOrganic Electronics: physics, materials, applications
Issue number7
Publication statusPublished - Nov 1 2009
Externally publishedYes


  • Atomic layer deposition
  • Conjugated polymer
  • Encapsulation
  • Lifetime
  • Organic solar cells
  • Photovoltaic

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering


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