Advancing perovskite solar cells: Optical characterization and performance enhancement via spectroscopic ellipsometry

Optimizing light collection is essential to enhance power conversion efficiency in perovskite solar cells (PSCs). Understanding the optical characteristics of perovskite materials is key to designing improved structures and enhancing device performance. Precise characterization of these optical properties, especially in complex, multi-layered systems, is crucial. Spectroscopic ellipsometry (SE) is a vital technique for analyzing thin films. It provides insights into optical constants such as the dielectric function, refractive index, and absorption coefficient. SE is commonly used to study perovskite thin films, focusing on aspects such as optical model generation and data analysis, temperature-dependent behavior, thermal degradation, and the chemical composition of perovskites, all of which critically affect the performance and stability of solar cell devices. This review discusses recent progress in SE-based techniques as an effective tool for thoroughly and systematically evaluating the optoelectronic properties of perovskite thin films. Specifically, this review examines the analytical approaches for analyzing the perovskite properties, selecting theoretical optical models and data fitting methods, extracting key optical constants, and interpreting SE measurements. Further, the current advancement and prospects in using SE for optimizing the performance and stability of PSCs are discussed, which serve as critical points in accelerating the commercialization of PSCs in the future. • Provides in-depth insights into overcoming key challenges related to perovskite solar cell absorption and stability. • Highlights recent advancements in the optical characterization of perovskite materials. • Reviews the latest spectroscopic ellipsometry (SE) developments for analyzing perovskite thin films. • Discusses innovative strategies for optical modeling, SE data analysis, and interpretation to improve film performance. • Offers a forward-looking perspective on future trends and opportunities for SE analysis in perovskite research.