In Situ Grazing‐Incidence Wide‐Angle Scattering Reveals Mechanisms for Phase Distribution and Disorientation in 2D Halide Perovskite Films
Abstract
2D hybrid halide perovskites with the formula (A′)2(A)n‐1PbnI3n+1 have remarkable stability and promising efficiency in photovoltaic and optoelectronic devices, yet fundamental understanding of film formation, key to optimizing these devices, is lacking. Here, in situ grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) is used to monitor film formation during spin‐coating. This elucidates the general film formation mechanism of 2D halide perovskites during one‐step spin‐coating. There are three stages of film formation: sol–gel, oriented 3D, and 2D. Three precursor phases form during the sol–gel stage and transform to perovskite, first giving a highly oriented 3D‐like phase at the air/liquid interface followed by subsequent nucleations forming slightly less oriented 2D perovskite. Furthermore, heating before crystallization leads to fewer nucleations and faster removal of the precursors, improving orientation. This outlines the primary causes of phase distribution and perpendicular orientation in 2D perovskite films and paves the way for rationally designed film fabrication techniques.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 02, 2020
- Source ID
- 10.1002/adma.202002812
Entities
People
- Ido Hadar
- Joseph W Strzalka
- Justin M Hoffman
- Lin Chen
- Mercouri Kanatzidis
- Nathan C Flanders
- Qingteng Zhang
- Richard D. Schaller
- Shelby A. Cuthriell
- William Dichtel
Organizations
- Air Force Research Laboratory
- Argonne National Laboratory
- Army Research Office
- Northwestern University
- Office of Basic Energy Sciences
- Office of Naval Research
- Office of Science
- United States Department of Energy