Charge dynamics in solar cells with a blend of π-conjugated polymer-fullerene studied by transient photo-generated voltage

Bao Fu Ding, Wallace C.H. Choy, Wai Ming Kwok, Chuan Dao Wang, Keith Y.F. Ho, Dixon D.S. Fung, Feng Xian Xie

Research output: Journal article publicationJournal articleAcademic researchpeer-review

3 Citations (Scopus)

Abstract

The biphasic feature of transient photo-generated voltage (TPV) is investigated in organic solar cells (OSCs) with a blend active layer of poly(3-hexylthiophene) (P3HT) and phenyl C61 butyric acid methyl ester (PCBM). The positive and negative components in biphasic TPV are explained through PCBM only and P3HT only devices. The negative and positive components are ascribed to the dipole formation at the buried interface of P3HT/indium tin oxide (ITO) and PCBM/ITO respectively. Based on these findings, two fundamental phenomena are revealed as follows: (1) interfacial modification on the buried interface inverts the negative component in biphasic TPV to a positive component, which prevents the leakage current channel in the conventional OSC structure; and (2) the solvent chosen transforms the positive component in biphasic TPV into a negative signal, which blocks the leakage current channel in the inverted OSC structure. Consequently, the study of TPV polarity provides the justification of the interaction at the buried interface. Besides, the decay of TPV is found to be bi-exponential, which can be used as a tool to estimate the degree of charge balance in OSCs.
Original languageEnglish
Pages (from-to)8397-8402
Number of pages6
JournalPhysical Chemistry Chemical Physics
Volume14
Issue number23
DOIs
Publication statusPublished - 21 Jun 2012

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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