Electroabsorption and oppositely directed built-in fields in a photovoltaic organic heterostructure
- First Online:
- Cite this article as:
- Blinov, L.M., Lazarev, V.V. & Yudin, S.G. Crystallogr. Rep. (2013) 58: 906. doi:10.1134/S1063774513060060
- 61 Downloads
The directions and intensities of local electric fields spontaneously built into organic nanoscale structures of Schottky-diode type, indium tin oxide (ITO)-CuPc-Al and ITO-C60-Al, with donor and acceptor layers of copper phthalocyanine (CuPc) and fullerene (C60) have been investigated using an improved spectral electroabsorption technique. It is established that, in the absence of external field and illumination, the built-in fields in the bulk of these structures are directed differently: from Al to ITO in the case of CuPc and from ITO to Al in the case of C60. The best studied photovoltaic heterostructure ITO-CuPc-C60-Al contains simultaneously strong built-in fields in CuPc and C60 layers, with strengths of about 15 and −22 V/μm, respectively. A high (on the order of 10−3 C/m2) positive space charge arises at the donor-acceptor interface, and the oppositely directed fields may either increase or reduce the efficiency of light-energy converters, depending on the heterostructure parameters.