Decoupling the optical and electrical properties of subphthalocyanine/C70 bi-layer organic photovoltaic devices: Improved photocurrent while maintaining a high open-circuit voltage and fill factor

Chih Chien Lee, Wei Cheng Su, Yi Sheng Shu, Wen Chang Chang, Bo Yao Huang, Ya Ze Lee, Tsung Hao Su, Kuan Ting Chen, Shun Wei Liu

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

We demonstrate a simple method for achieving high-performance subphthalocyanine (SubPc)/C70 bi-layer organic photovoltaic (OPV) devices through the changing of the C70 thickness. The optical and electrical properties of the OPV devices were decoupled and could be individually manipulated to obtain a significantly increased short-circuit current density (JSC) without reducing the open-circuit voltage and the fill factor. The thickness-independent electrical property of the C70 layer was systematically studied in terms of the dark currents of the OPV devices and the carrier mobilities of the organic layers; the results indicate that the considerable difference in mobility between SubPc and C70 is not detrimental, while the optical-field distribution can be optimized by tuning the C70 thickness. The power conversion efficiency was improved from 2.7 to 4.2% by optimizing the C70 thickness. The optical effect upon the change in the C70 thickness was thoroughly investigated by calculating the optical-field profile and the power dissipation inside the OPV devices on the basis of the transfer matrix method. The calculated results suggest that the optical-field intensity is insufficient in predicting the trend in JSC. Instead, the power dissipation involving the absorption properties of materials and the optical-field distribution of OPV devices can provide deeper insight into the optical condition and indicates the importance of optimizing the film thickness in bi-layer OPV devices. This journal is

Original languageEnglish
Pages (from-to)5617-5626
Number of pages10
JournalRSC Advances
Volume5
Issue number8
DOIs
Publication statusPublished - Jan 1 2015
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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