ИСТИНА

Recently our group has developed a new strategy of perovskite thin film fabrication using novel reactant compounds, reactive polyiodide melts – the so-called RPM-process [1]. The RPMs can be easily obtained from solid I2 and MAI, exhibit very low melting points and high chemical activity. They are liquid a room temperature, readily react with lead-containing compounds to form the perovskite phase CH3NH3PbI3 and do not require the use of any solvent. We found that the RPM-process is reversible – if the sufficient iodine pressure is built up above the perovskite film, the perovskite structure gets destroyed to form RPM. Once being formed, RPM acts as a liquid medium that facilitates the recrystallization of perovskite grains. Using scanning electron microscopy, x-ray diffraction, time-resolved luminescence spectroscopy we showed that iodine treatment is beneficial for the overall quality of perovskite thin films that were fabricated by means of classical solution-based approaches and result in the increase of the average grain size, crystallinity, lifetime of charge carriers. We also realized that the excess of iodine can be liberated from the perovskite film in the RPM-process by either chemical or physical means. Via iodine-gas treatment of perovskite films deposited on top of copper films we managed to obtain the interpenetrating CH3NH3PbI3/CuI heterostructures. References [1] Petrov, A.A., Belich, N.A., Grishko, A.Y., Stepanov, N.M., Dorofeev, S.G., Maksimov, E.G., Shevelkov, A.V., Zakeeruddin, S.M., Graetzel, M., Tarasov, A.B. and Goodilin, E.A., Materials Horizons (2017), 4(4), pp.625-632