A review of characterization of perovskite film in solar cells by spectroscopic ellipsometry

Perovskite materials have performed so excellently in semiconductor field due to their fascinating photoelectric properties. As solar cell absorber materials , they have attracted more and more interests. Quantitative characterization on the optical parameters and geometric features of the perovskite film is crucial to optimize its design of material and structure, and then to improve the photoelectric performance of perovskite solar cells (PSCs). The spectroscopic ellipsometry (SE) has been used to characterize the optical properties and thickness of nano-scale thin films in photovoltaic system , LED, organic panel, etc. It starts from the measurement of amplitude ratio spectrum (Psi-wavelength) and phase shift spectrum (Delta-wavelength) of polarized lights upon reflection or transmission on a sample. The literatures related to measurement and analysis of perovskite thin film for solar cells using SE were reviewed as: the analysis of related factors of perovskite properties; the selection of SE measurement parameters; the establishment of optical model for theoretical generated data; the selection of fitting method for experimental data; the extraction of optical constants and geometric parameters ; and the characterization of photoelectric properties of the perovskites, etc. The review systematically and comprehensively summarized the usage of SE as a powerful tool for characterizing the optoelectronic properties of perovskite films and PSCs.