New Features of Photochemical Decomposition of Hybrid Lead Halide Perovskites by Laser Irradiation

Abstract

We found that laser irradiation, being widely used in perovskite photovoltaics for both laser scribing and materials characterization, inevitably causes a cascade of complex photo- and thermochemical conjugated reactions, material melting, and ablation with deep morphological and composition changes of perovskite thin films over a much larger area compared to the initial laser spot. A crucial issue in the advancing or suppression of these degradation processes is related to the origin of the surrounding atmosphere. In particular, an effective approach utilizing an inert gas flow directed onto the exposed area is suggested for the first time to eliminate the negative consequences of perovskite laser scribing. This finding is naturally related to experimental observations of spreading the volatile decomposition products, including elemental iodine, over the pristine perovskite material, regardless of its composition, followed by laser-induced formation of liquid polyiodides. Suppression of decomposition product amount by proper selection of the gas atmosphere and power regime of the laser treatment is of interest to enhance the scribing procedure.

Reproducible X‐ray Imaging with a Perovskite Nanocrystal Scintillator Embedded in a Transparent Amorphous Network Structure

“…Enormous efforts to design more stable perovskite structure, [6,25] unfortunately, the unsettled issue for the practical application of CsPbBr 3 NCs is that the perovskite could hardly be isolated from environment species such as moisture and oxygen, which have been verified to accelerate degradation under irradiation. [26] Moreover, the reported stability tests of perovskite scintillators are mostly under a relative low dose of X-ray exposure (below 1 mGy air s −1 ) so far, while practical applications are accompanied with high-dose irradiation. [27,28] Indeed, high-dose of the X-ray is conducive to improve the imaging contrast as show in Figure S1 (Supporting Information), meeting the steadily growing demand of the spatial images resolution.…”

New Aspects of Copper Electrode Metamorphosis in Perovskite Solar Cells

“…) 17 and atoms, 18 formation of molecular iodine I 2 , 19,20 and, as often for final stages, generation of highly corrosive polyiodide species and PbI 2 as byproducts. 6,16 Iodine migration is considered to be the reason for metal electrode corrosion with formation of corresponding metal iodides: AgI 21,22 and CuI. 14,23 Involvement of polyiodides into the corrosion process increases drastically the rate of corrosion and promotes the formation of organohalides (e.g., MA 2 Au 2 I 6 ) as recently found.…”

“…Photochemical activity of HPs strongly depends on light wavelength 15 and intensity. 16 According to the large number of research studies in this field, light soaking of lead halide perovskites promotes the generation and migration of iodide vacancies (V I…”

Methylammonium Polyiodides in Perovskite Photovoltaics: From Fundamentals to Applications

“…According to Raman spectroscopy, methylammonium polyiodides have three characteristic vibrations near 110 cm −1 , 145 cm −1 and 170 cm −1 that correspond to an I − 3 symmetrical stretch vibrations, I − 3 asymmetrical stretch vibrations and vibrations of solvating I 2 molecular units, respectively (Petrov et al, 2017a;Turkevych et al, 2019;Udalova et al, 2020).…”

“…It is known that intensive irradiation of hybrid perovskites leads to the release of degradation products I 2 , Br 2 , MAI, and MABr (Abdelmageed et al, 2016;Pistor et al, 2016;Wang et al, 2016;Ceratti et al, 2018). It was shown recently, that the accumulation of these compounds leads to the formation of RPM in perovskite films (Shlenskaya et al, 2018a;Udalova et al, 2020). Particularly, the fast formation of RPM under laser beam was confirmed for the six most relevant perovskite compositions: MAPbI 3 , MA 0.15 FA 0.85 PbI 3 , FAPbI 3 , FA 0.85 Cs 0.15 PbI 3 , MA 0.25 FA 0.75 PbI 2.25 Br 0.75 , and Cs 0.05 MA 0.15 FA 0.8 PbI 2.5 Br 0.5 (Udalova et al, 2020).…”