PEROVSKITES FOR PHOTOVOLTAICS: PHOTOINDUCED PHYSICAL CHANGES

Organic-inorganic halide perovskites are in consensus to revolutionize the field of photovoltaics and optoelectronic devices due to their superior optical and electronic properties which are unprecedented in comparison to those of other solution processed semiconductors. These hybrid materials are used as light absorbers and also as charge carries which makes them very versatile to be implemented and studied in multitude of fields. Traditionally, the working paradigm in solar cells and optoelectronic devices` characterization has been that the properties of photovoltaic materials remain stable following illumination of varying times and intensities. However, a growing number of reports on prolonged illumination-dependent physical changes (photoinduced changes) in perovskite films and perovskite based devices. The changes are reversible and range from structural transformations and differences in optical characteristics, to an increase in optoelectronic properties and physical parameters.

We review photoinduced changes in three reported model systems which display changes under prolonged illumination. The systems are: i) a free-standing perovskite film on a glass substrate, ii) a symmetrical system with non-selective electrical contacts, iii) a working perovskite solar cell.