Organic Schottky barrier photovoltaic cells based on MoOx/C60

We report that the performance of indium tin oxide/molybdenum oxide/fullerene (ITO/MoOx/C60) photovoltaic cells is highly sensitive to the method of depositing MoOx film. The highest open-circuit voltage and short-circuit current are obtained using thermally evaporated MoOx. In contrast, sputtered MoOx produces lower efficiencies. X-ray and ultraviolet photoemission analyses indicate that pristine thermally evaporated MoOx has a high work function of 6.8 eV and Mo6+ oxidation state, whereas argon-sputtered MoOx is characterized by lower work function and coexistence of both Mo6+ and Mo5+ states. The photovoltaic performance of the ITO/MoOx/C60 cells is consistent with MoOx functioning as the Schottky barrier contact.

[1]  Wolfgang Kowalsky,et al.  Role of the deep-lying electronic states of MoO3 in the enhancement of hole-injection in organic thin films , 2009 .

[2]  D. Milliron,et al.  Surface oxidation activates indium tin oxide for hole injection , 2000 .

[3]  D. Morel,et al.  Organic photovoltaic cells. Correlations between cell performance and molecular structure , 1984 .

[4]  Bernard Kippelen,et al.  Interface modification of ITO thin films: organic photovoltaic cells , 2003 .

[5]  Vishal Shrotriya,et al.  Transition metal oxides as the buffer layer for polymer photovoltaic cells , 2006 .

[6]  Shui-Tong Lee,et al.  Modification of the hole injection barrier in organic light-emitting devices studied by ultraviolet photoelectron spectroscopy , 2000 .

[7]  J. Bernède,et al.  MoO3 surface passivation of the transparent anode in organic solar cells using ultrathin films , 2009 .

[8]  G. Hadziioannou,et al.  On interface dipole layers between C60 and Ag or Au , 2002 .

[9]  R. Colton,et al.  Electrochromism in some thin‐film transition‐metal oxides characterized by x‐ray electron spectroscopy , 1978 .

[10]  Franco Cacialli,et al.  Indium-tin oxide treatments for single- and double-layer polymeric light-emitting diodes: The relation between the anode physical, chemical, and morphological properties and the device performance , 1998 .

[11]  T. Fleisch,et al.  An XPS study of the UV reduction and photochromism of MoO3 and WO3 , 1982 .

[12]  T. Riedl,et al.  Highly efficient simplified organic light emitting diodes , 2007 .

[13]  Do-Young Kim,et al.  The effect of molybdenum oxide interlayer on organic photovoltaic cells , 2009 .