Effect of non-stoichiometry of initial reagents on morphological and structural properties of perovskites CH3NH3PbI3

• Published in: Nanoscale research letters 2019-01, Vol.14 (1), p.1-4, Article 4
• Main Authors: Belous, Anatolii, Kobylianska, Sofiia, V’yunov, Oleg, Torchyniuk, Pavlo, Yukhymchuk, Volodymyr, Hreshchuk, Oleksandr
• Format: Article
• Language: English
• Subjects: Anisotropy; Chemical reaction; Chemistry and Materials Science; Electron microscopy; Heat treatment; Iodine; Lead; Materials Science; Metal halide perovskite; Metal halide perovskite materials and devices; Microstructure; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Particle shape; Perovskite structure; Perovskites; Properties (attributes); Raman spectroscopy; Reagents; Stoichiometry
• ISSN: 1931-7573; 1556-276X
• DOI: 10.1186/s11671-018-2841-6

The properties of films of organic-inorganic perovskites CH 3 NH 3 PbI 2.98 Cl 0.02 depending on the ratio of starting reagents in solutions (PbI 2 :{CH 3 NH 3 I + CH 3 NH 3 Cl}) has been investigated. It was found that the formation of the perovskite structure with the ratio of the initial reagents PbI 2 : CH 3 NH 3 I = 1:1 occurs at 70–80 °C, and with the increase of the temperature of thermal treatment to 120 °C, the thermal destruction of the perovskite begins. When the ratio of the starting reagents PbI 2 : CH 3 NH 3 I = 1:2, the formation of the perovskite structure occurs through the intermediate compound (CH 3 NH 3 ) 2 PbI 4 , and when the ratio is 1:3—(CH 3 NH 3 ) 3 PbI 5 and (CH 3 NH 3 ) 2 PbI 4 . Independent on the ratio of the initial components (CH 3 NH 3 I:PbI 2 ), the ratio between the content of lead and iodine in the films remains unchanged, that is why a significant difference in the film properties could be explained by the anisotropy of the particle shape, which is consistent with the data of electron microscopy and X-ray diffractometry.