Perovskite crystallization dynamics during spin casting: an in situ wide angle X-ray scattering study

DOI: 10.1021/acsaem.9b02470

Authors: Noura Alhazmi (University of Sheffield) , Edwin Pineda (University of Sheffield) , Jonathan Rawle (Diamond Light Source) , Jonathan R Howse (University of Sheffield) , Alan D. F. Dunbar (University of Sheffield)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acs Applied Energy Materials

State: Published (Approved)
Published: June 2020
Diamond Proposal Number(s): 14937

Abstract: In this study in situ wide angle X-ray scattering (WAXS) has been measured during the spin coating process used to make the precursor films required for the formation of thin films of perovskite. A customized hollow axis spin coater was developed to permit the scattered X-rays to be collected in transmission geometry during the deposition process. Spin coating is the technique most commonly used in laboratories to make thin perovskite films. The dynamics of spin casting MAPbI3-xClx and FAPbI3-xClx films have been investigated and compared to investigate the differences between the dynamics of MAPbI3-xClx and FAPbI3-xClx film formation. In particular we focus on the crystallization dynamics of the precursor film formation. When casting MAPbI3-xClx we observed relatively fast 1D crystallization of the intermediate product MA2PbI3Cl. There was an absence of the desired perovskite phase formed directly; it only appeared after an annealing step which converted the MA2PbI3Cl to MAPbI3. In contrast, slower crystallization via a 3D precursor was observed for FAPbI3-xClx film formation compared to MAPbI3-xClx. Another important finding was that some FAPbI3-xClx perovskite was generated directly during spin casting before annealing. These findings indicate that there are significant differences between the crystallization pathways for these two perovskite materials. These are likely to explain the differences in the lifetime of the resulting perovskite solar cell devices produced using FA and MA cations.

Subject Areas: Materials, Energy


Instruments: I07-Surface & interface diffraction

Documents:
acsaem.9b02470.pdf