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 5 K. 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 30 K recovers the band-to-band PL, while the light-induced defect states disappear concurrently.

中文翻译：

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低温下CH3NH3PbI3中亚稳态缺陷状态的产生和退火

甲基铵碘化铅（CH ₃ NH ₃ PbI ₃）是一种广泛用于光电应用的有机-无机钙钛矿，已知在光子能量约为2.7 eV或更高的光照射下会解离。在这里，我们表明光致离解不限于环境温度，甚至可以在5 K下观察到。N–H键的光致离解导致形成亚稳态。光致发光（PL）测量揭示了在带隙内位于100 meV的缺陷状态的形成。这伴随着频带间PL的猝灭一个数量级。缺陷的产生是可逆的，在30 K退火可恢复带间PL，而光诱导的缺陷状态则同时消失。