In-Situ Monitoring of Perovskite Thin Film Formation by High-Speed Optical Reflectance Spectroscopy

37th European Photovoltaic Solar Energy Conference and Exhibition; 596-600
In this paper, the complete formation of various perovskite thin films during spin-coating and subsequent annealing is monitored in-situ by high-speed optical reflectance spectroscopy. Furthermore, first results for anti-solvent drip processes and the deposition of perovskite semiconductors on top of CIGS-based samples for tandem applications are presented. It is shown, that a complete “fingerprint” of the film formation process can be obtained and crucial properties like the absorption edge and its evolution during film formation can be deduced. The method also allows for real-time measurements of the amount of the remaining precursor wet-film. All this information is well-suited for tailoring film properties and identifying new paths for the optimization of performance or yield. Hence, this technology can enable and accelerate process development for perovskite thin films. This paper focuses on the experimental implementation of the in-situ measurements and presents first results on absorption edge evolution monitoring, spincoating kinetics and annealing phase transformations.