Semiconductor Physics, Quantum Electronics & Optoelectronics. 2007. V. 10, N 2. P. 081-085.
Organic iso-type pentacene – lead phthalocyanine heterostructures
Institute of Physics, NAS of Ukraine, 46, prospect Nauky, 03680 Kyiv, Ukraine
Phone: +380 44-525 09 12; fax +380 44-525 15 89
E-mails: yavertsi@iop.kiev.ua; lutsyk@univ.kiev.ua
Abstract. The photovoltaic properties of organic iso-type heterostructures based on
pentacene (Pn) and lead phthalocyanine (PbPc) prepared by thermal deposition at
different substrate temperatures (T s ) are investigated. It is shown that, at modulated
illumination for Pn/PbPc heterostructures prepared at Т s = 300 K, the reversal of a sign is
observed in photovoltage spectra. The properties of the structures are well described by
the Van Opdorp model that indicates the presence of the high surface recombination rate
of charge carriers at the interface of heterostructure components. At this, the contribution
of heterostructure components to the photovoltage formation can be changed with
unmodulated monochromatic additional illumination. In Pn/PbPc heterostructures
prepared at T s = 370 K, there is no reversal of the photovoltage sign, and the photo-
voltage is significantly (up to twice) higher in comparison with both heterostructures
obtained at T s = 300 K and separate layers of components (Pn and PbPc). This is the
evidence for the low recombination rate of charge carriers at the interface of Pn/PbPc
heterostructures prepared at T s = 370 K.
Keywords: iso-type heterostructure, photovoltage spectra, lead phthalocyanine,
pentacene.
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