X‐Ray Microscopy of Halide Perovskites: Techniques, Applications, and Prospects

Abstract

X-ray microscopy can provide unique chemical, electronic, and structural insights into perovskite materials and devices leveraging bright, tunable synchrotron X-ray sources. Over the last decade, fundamental understanding of halide perovskites and their impressive performance in optoelectronic devices has been furthered by rigorous research regarding their structural and chemical properties. Herein, studies of perovskites are reviewed that have used X-ray imaging, spectroscopy, and scattering microscopies that have proven valuable tools toward understanding the role of defects, impurities, and processing on perovskite material properties and device performance. Together these microscopic investigations have augmented our understanding of the This article is protected by copyright. All rights reserved. 2 internal workings of perovskites and help steer the perovskite community toward promising directions. In many ways, X-ray microscopy of perovskites is still in its infancy, which leaves many exciting paths unexplored including new super-resolution, multimodal, in situ, and operando experiments. To explore possibilities, pioneering X-ray microscopy along these lines is briefly highlighted from other semiconductor systems including silicon, CdTe, GaAs, CuIn x Ga 1-x Se 2 , and organic photovoltaics. An overview is provided on the progress made in utilizing X-ray microscopy for perovskites and present opportunities and challenges for future work.

Europium Addition Reduces Local Structural Disorder and Enhances Photoluminescent Yield in Perovskite CsPbBr3

“…This technique rasters a 60 nm full‐width half‐maximum (FWHM) monochromatic X‐ray probe across the sample and uses a 2D panel detector to collect the scattering produced at each point, generating a rich, nanoscale map of the structural properties. [ 40 ] nXRD is highly sensitive both in terms of detection limit and spatial resolving power. Minority of crystal orientations and phases barely present or undetectable in benchtop XRD data can often be seen clearly in nXRD, although the total area sampled is limited currently to several hundreds per square micrometer.…”

Advanced Characterization Techniques for Overcoming Challenges of Perovskite Solar Cell Materials

“…Recently, remarkable progresses have been achieved in advanced characterization techniques for perovskite materials or solar cells under in situ conditions. [119][120][121] The term "in situ" means "in place" in Latin, and is used to describe a measurement emulating operating conditions. As such, in situ characterization can be used to more accurately describe mechanisms when compared to ex situ techniques.…”

“…Last, ex situ X‐ray assisted spectroscopies such as XRD, XPS, and XRF can characterize electronic and structural information of perovskite materials. [ 120 ] Though, the evolution of electronic and structural information can more accurately be measured by in situ X‐ray assisted measurement tools, which are valuable characteristics to assess their performance and stability. In these regards, the development of the in situ characterization techniques applied into the perovskite materials will be introduced in the following sub‐sections: in situ EM, in situ optoelectronic measurement, and in situ X‐ray assisted measurement.…”

Defect activation and annihilation in CIGS solar cells: an operando x-ray microscopy study

“…For this purpose, the dose density in the layer stack has been simulated using a modified version of the Monte-Carlo code Penelope [57]. Then, the interaction radius has been determined from the three-dimensional dose density using the same procedure as for perovskite solar cells in [32]. For the CIGS samples and measurement geometry of this study, the simulations yielded an interaction radius of 160 nm.…”