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  Lang, F.; Shargaieva, O.; Brus, V.V.; Rappich, J.; Nickel, N.H.: Creation and annealing of metastable defect states in CH₃NH₃PbI₃ at low temperatures. Applied Physics Letters 112 (2018), p. 081102/1-3

10.1063/1.5019921
Open Access Version

Abstract:
Methylammonium lead iodide (CH3NH3PbI3), an organic-inorganic perovskite widely used for optoelectronic applications, is known to dissociate under illumination with light at photon energies around 2.7 eV and higher. Here, we show that photo-induced dissociation is not limited to ambient temperatures but can be observed even at 5K. The photo-induced dissociation of N–H bonds results in the formation of metastable states. Photoluminescence (PL) measurements reveal the formation of defect states that are located 100 meV within the bandgap. This is accompanied by a quenching of the band-to-band PL by one order of magnitude. Defect generation is reversible and annealing at 30K recovers the band-to-band PL, while the light-induced defect states disappear concurrently.