Photoactive donor-acceptor thin films as prospective materials for evaporated bulk heterojunctions of molecular semiconductors

摘要

The formation of evaporated blends of organic donor and acceptor molecules has gained interest recently as active layers in organic photovoltaic cells and organic field effect structures. In this contribution we report about the combination of phthalocyanines as electron donors absorbing in the red part of the spectrum and perylene imids as electron acceptors absorbing in the green part of the spectrum providing almost perfect coverage of the visible range. Mixed films were successfully created by simultaneous physical vapour deposition of the molecules. Using transmission spectroscopy, structure analysis and (photo-)conductivity measurements electronic and optical properties were investigated and compared with the properties of the pure films. The observed spectral dependence of the photoconductivity indicated a potential use of such materials in organic photovoltaic cells.