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This paper deals with the study of light conversion efficiency of organic photovoltaic cells with an inkjet-printed graphene oxide layer. The graphene oxide is used in this experiment as a hole-extracting, electron blocking layer in bulk heterojunction organic solar cells based on DPP(TBFu)2:PC60BM blend. It is also studied the influence of the GO reduction (chemically, by UV radiation and by annealing) on the final efficiency of photovoltaic conversion. Power conversion efficiency and the transport of charge carriers are evaluated by measuring of current-voltage characteristics and mainly by impedance spectroscopy analysis. In this regard, using of graphene oxide and its reduced form showed negative influence on the device performance caused by an inefficient charge carrier collection at the short-circuit condition.

The paper deals with the study of optical properties of graphene oxide (GO) by inkjet printing. Defined structure of GO can be obtained by reducing of prepared layers either by heating or by UV radiation (rGO). The dispersion function for refractive index and extinction coefficient of GO and both rGO thin films were measured by spectroscopic ellipsometry in the wavelength range of 200 – 850 nm. Spectroscopic ellipsometry (SE) was used characterize the optical response of layer of GO reduced by UV and thermal reduction GO in visible range.

The paper deals with the study of optical and electrical properties of inkjet-printed graphene oxide (GO) layers, which can be used e.g. for the preparation of various types of electronic devices. To ensure stable inkjet printing conditions of GO solution, mixture was thoroughly stirred for 1 h at room temperature or sonicated in the bath for 30 min. The thicknesses of prepared layers were determined by spectroscopic ellipsometry and profilometry. An electrical conductivity of GO was increased by the multistep reduction (due to annealing) – the conductivity was changed by these processes about seven orders of magnitude (GO is an isolator and reduced GO is a conductor). For electrical and dielectric measurements, samples with GO and mixture of GO with PEDOT were prepared. All current-voltage characteristics have a diode character. From AC measurements the bulk electrical conductivity and geometric capacity of prepared layers were determined.