How to GIWAXS: Grazing Incidence Wide Angle X‐Ray Scattering Applied to Metal Halide Perovskite Thin Films

Abstract

The frequency of reports utilizing synchrotron‐based grazing incident wide angle X‐ray scattering (GIWAXS) to study metal halide perovskite thin films has exploded recently, as this technique has proven invaluable for understanding several structure‐property relationships that fundamentally limit optoelectronic performance. The GIWAXS geometry and temporal resolution are also inherently compatible with in situ and operando setups (including ISOS protocols), and a relatively large halide perovskite research community has deployed GIWAXS to unravel important kinetic and dynamic features in these materials. Considering its rising popularity, the aim here is to accelerate the required learning curve for new experimentalists by clearly detailing the underlying analytical concepts which can be leveraged to maximize GIWAXS studies of polycrystalline thin films and devices. Motivated by the vast range of measurement conditions offered, together with the wide variety of compositions and structural motifs available (i.e., from single‐crystal and polycrystalline systems, to quantum dots and layered superlatices), a comprehensive framework for conducting effective GIWAXS experiments is outlined for different purposes. It is anticipated that providing a clear perspective for this topic will help elevate the quality of future GIWAXS studies—which have become routine—and provide the impetus required to develop novel GIWAXS approaches to resolve unsettled scientific questions.

Toward Weak Epitaxial Growth of Silicon Phthalocyanines: How the Choice of the Optimal Templating Layer Differs from Traditional Phthalocyanines

“…To quantify the orientation distribution of the MPcs, we plotted the scattering intensity as a function of the azimuthal angle, χ, where χ is the angle with respect to the q z axis. This means that χ = 0° lies directly along the out-of-plane ( q z ) axis, while χ = 90° lies directly along the in-plane ( q r ) axis . The azimuthal integration of the GIWAXS results for F 10 -SiPc films deposited on p -6P and p -6PF demonstrated good agreement with the powder diffraction pattern for F 10 -SiPc based on single-crystal X-ray diffraction data (Figure S15).…”

“…This means that χ = 0°lies directly along the out-of-plane (q z ) axis, while χ = 90°lies directly along the in-plane (q r ) axis. 66 The azimuthal integration of the GIWAXS results for F 10 -SiPc films deposited on p-6P and p-6PF demonstrated good agreement with the powder diffraction pattern for F 10 -SiPc based on single-crystal X-ray diffraction data (Figure S15). The same is true for F 16 -CuPc (Figure S15), and this agreement provides strong confidence in the scattering data used for analyzing the film structure.…”

Unraveling Interface-Driven and Loss Mechanism-Centric Phenomena in 3D/2D Halide Perovskites: Prospects for Optoelectronic Applications

“…To ensure the formation of the desired bilayer stack with a uniform distribution of ions, it is crucial to conduct a thorough initial characterization. To facilitate this essential step, synchrotron-based GIWAXS has been widely employed to probe the structural characteristics of perovskite thin films . Mushtaq et al used this technique to understand the depth-dependent crystal structure of (PEA) 2 Cs 4 Pb 5 Br 16 .…”

Bilayer 2D-3D Perovskite Heterostructures for Efficient and Stable Solar Cells

“…More technical comprehensive understanding of the setup and data analysis of GIWAXS measurements can be found in our recent review paper. 51 Time-of-flight secondary-ion mass spectrometry (TOF-SIMS) is another useful tool to gain chemical and molecular insights into the depth profile of bilayer 2D-3D PHSs, especially those with 2D perovskite domains accumulating at the buried interface or grain boundaries. Argon sputter etching-assisted Xray photoelectron spectroscopy (XPS) can also study the depth-dependent chemical environment of the bilayer 2D-3D PHSs but needs more delicate control on etching time.…”

“…Increasing the incidence grazing angle of GIWAXS can improve the X-ray penetration depth to interact with the 2D perovskite layer at the buried interface, accessing its information on 2D crystallographic planes and orientations. More technical details and a comprehensive understanding of the setup and data analysis of GIWAXS measurements can be found in our recent review paper . Time-of-flight secondary-ion mass spectrometry (TOF-SIMS) is another useful tool to gain chemical and molecular insights into the depth profile of bilayer 2D-3D PHSs, especially those with 2D perovskite domains accumulating at the buried interface or grain boundaries.…”