I₂ vapor-induced degradation of formamidinium lead iodide based perovskite solar cells under heat–light soaking conditions

Abstract

We reveal an iodine vapor-induced degradation mechanism in formamidinium–lead-iodide-based perovskite solar cells stressed under combined heat and light illumination.

Secondary Ion Mass Spectrometry (SIMS) for Chemical Characterization of Metal Halide Perovskites

“…[111] Another thermal-and light-induced degradation mechanism is the release of I 2 . [112] ToF-SIMS results showed that the PbI 2 concentration decreases in PbI 2 film during heating-light soaking at 80 °C under solar cell operational condition, suggesting that PbI 2 decomposes to Pb and I 2 . [112] In perovskite film, the PbI 2 concentration increases but the MA concentration decreases after the heating-light soaking test.…”

“…[112] ToF-SIMS results showed that the PbI 2 concentration decreases in PbI 2 film during heating-light soaking at 80 °C under solar cell operational condition, suggesting that PbI 2 decomposes to Pb and I 2 . [112] In perovskite film, the PbI 2 concentration increases but the MA concentration decreases after the heating-light soaking test. Therefore, combining with other investigations, it was suggested that the loss of MA under heating-light soaking triggers the release of I 2 vapor, which deteriorates neighboring perovskite and further leads to the decomposition of perovskite.…”

Decoupling Contributions of Charge‐Transport Interlayers to Light‐Induced Degradation of p‐i‐n Perovskite Solar Cells

“…However, the progress in improving the stability of PSCs is far from being satisfactory, and therefore, short operation lifetimes represent the main obstacle for successful commercialization of perovskite photovoltaic technology . Complex lead halides with a perovskite crystal structure were shown to be very sensitive substances readily decomposing under exposure to moisture (hydrolysis), oxygen, and light (photooxidation), and reactive chemical vapors such as iodine . While these extrinsic degradation pathways can be mitigated by encapsulation of perovskite films and their isolation from aggressive environment, a particular concern is raised about intrinsic stability of complex lead halides, because they can decompose at elevated temperatures and under light exposure even in inert atmosphere .…”

Multi-component engineering to enable long-term operational stability of perovskite solar cells

“…Stable PSCs under 85 • C and one sun illumination for 1000 h have not been reported yet, though promising results for 500 h have been demonstrated [35,36]. Moreover, under constant light and heat, PSCs perform worse if analysed under open circuit voltage conditions than under the MPP tracking mode, indicating that ion migration and charge accumulation are critical for the stability of PSCs [37,38]. Therefore, the long-term stability of PSCs analysed under the combination of light, elevated temperature and bias voltage is significantly important and can be considered as a prerequisite towards commercialization.…”

“…Therefore, the long-term stability of PSCs analysed under the combination of light, elevated temperature and bias voltage is significantly important and can be considered as a prerequisite towards commercialization. An important challenge originates from I 2 -induced degradation [38,39], thermal decomposition, ion migration, interface deterioration and their coupling with defects, leading to accelerated degradation processes. Particularly, the generation of I 2 vapour, which originates from either the oxidation of Iby photo-generated holes [40] or decomposition of the halide perovskite through the presence of defects in the bulk, is a self-catalysed reaction, and thus urgent innovative solutions are necessary to address this problem [38].…”