Nikolai Korneev’s research while affiliated with National Institute of Astrophysics, Optics and Electronics and other places

The goal of this work is to study the effect of annealing temperature Ta on the properties of CH3NH3PbI3 (MAPI) thin films deposited on glass substrate through structural, compositional, and optical characterization. The films were obtained by one-step deposition method in which an anti-solvent drip was implemented with some delay during spin coating of the precursor mixture, followed by thermal annealing to promote solvent evaporation and rapid crystallization of the film. Properties of the perovskite film after thermal annealing were characterized by different analytical methods. The morphology and roughness of the films were studied by scanning electron microscopy and atomic force microscopy. The crystalline phase was characterized by X-ray diffraction. The optical properties were also determined by UV–Vis spectroscopy. Finally, the elemental composition was analyzed by secondary ion mass spectroscopy. In the temperature range of 100–160 °C, variable average grain diameters between ~ 200 and ~ 500 nm were obtained. However, higher post-deposition thermal annealing temperatures produce clusters of PbI2 between CH3NH3PbI3 grain boundaries. XRD measurements showed a decrease in MAPI crystallite size and an increase in PbI2 crystallite size and amount with increasing annealing temperature. In addition, higher Ta results in a modification of the absorption/reflectance spectra and a red shift of an optical band gap. The results of this study can be useful to produce thin films of MAPI with tunable optical and electronic properties for optimizing the performance of photovoltaic devices.

We present results of theoretical and experimental study of photo-EMF induced by running grating in perovskite thin films, parameters such as electron and hole photoconductivity relaxation time, ambipolar diffusion length, minority carriers drift mobility are obtained.