EU PVSEC Programme Online
EU PVSEC 2021, 6 - 10 September 2021
Presentation: 3CO.6.3 Investigating the Phase Evolution of Multi-Cation Perovskite Absorbers during Evaporation
Type: Oral
Date: Wednesday, 8th September 2021
13:30 - 15:00
Author(s): K. Heinze, P. Stötzner, S. Förster, P. Wessel, R. Scheer, P. Pistor
Presenter / Speaker: K. Heinze, Martin Luther University, Halle (Saale), Germany
Event: Conference Conference
Session: 3CO.6 Advanced Characterisation Applied to Perovskite Solar Cells
Topic: 3. 1 Perovskites
Summary / Abstract: Recent research on perovskite absorber materials has moved away from single-cation materials with bandgaps of Eg = 1.45 eV (formamidinium lead iodide, FAPbI3), 1.55 eV (MAPbI3) or 1.75 eV (CsPbI3) towards mixed-cation, mixed-halide compositions of (Cs,FA,MA)Pb(I,Br)3. The mixing of cations greatly enhances stability while I and Br can be used to tune the bandgap. This way, a wide variety of compositions can be prepared and the optimum Eg can be set for single-junction and tandem devices. However, obtaining single phase material is rather challenging. Our research focuses on physical vapor deposition (PVD) of different perovskites for solar cell applications. Although perovskites are mostly prepared via wet-chemical deposition methods, PVD is particularly interesting due to its ability to up-scale towards industrial production. Our particular PVD setup allows in situ x-ray diffraction (XRD) measurements to monitor the phase evolution of different layers and compositions during deposition and annealing. This system allows us to observe the crystallization and phase evolution for layers with a minimal thickness of 10 nm in situ. Earlier, we were able to investigate the growth of methylammonium lead iodide (MAPbI3) in depth and showed that under optimized conditions, a thin PbI2 seed layer is formed previous to the growth of the perovskite material leading to efficiencies > 14%.