Evolution of Photoluminescence, Raman, and Structure of CH₃NH₃PbI₃ Perovskite Microwires Under Humidity Exposure.

ABSTRACT: Self-assembled organic-inorganic CH₃NH₃PbI₃ perovskite microwires (MWs) upon humidity exposure along several weeks were investigated by photoluminescence (PL) spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). We show that, in addition to the common perovskite decomposition into PbI₂ and the formation of a hydrated phase, humidity induced a gradual PL redshift at the initial weeks that is stabilized for longer exposure (~?21 nm over the degradation process) and an intensity enhancement. Original perovskite Raman band and XRD reflections slightly shifted upon humidity, indicating defects formation and structure distortion of the MWs crystal lattice. By correlating the PL, Raman, and XRD results, it is believed that the redshift of the MWs PL emission was originated from the structural disorder caused by the incorporation of H₂O molecules in the crystal lattice and radiative recombination through moisture-induced subgap trap states. Our study provides insights into the optical and structural response of organic-inorganic perovskite materials upon humidity exposure.

SUBMITTER: Segovia R 

PROVIDER: S-EPMC5842165 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature