Introduction to Advanced X-ray Diffraction Techniques for Polymeric Thin Films

Abstract

X-ray diffraction has been a standard technique for investigating structural properties of materials. However, most common applications in the organic materials community have been restricted to either chemical identification or qualitative strain analysis. Moreover, its use for polymeric thin films has been challenging because of the low structure factor of carbon and the thin film nature of the sample. Here, we provide a short review of advanced X-ray diffraction (XRD) techniques suitable for polymeric thin films, including the type of analysis that can be done and measurement geometries that would compensate low signals due to low carbon structure factor and the thin film nature of the sample. We will also briefly cover the χ-pole figure for texture analysis of ultra-thin film that has recently become commonly used. A brief review of XRD theory is also presented.

Unveiling the Importance of Precursor Preparation for Highly Efficient and Stable Phenethylammonium‐Based Perovskite Solar Cells

“…This implies that most of the crystals are aligned along two rotating axes (see "top view" in Figure 2f ) with some aligned by symmetry. [22,35] These results indicate that SP perovskite films have more uniform and oriented crystallites, in agreement with previous XRD and DLS results.…”

“…In contrast, the pole figure map of the SP perovskite film (Figure d) shows the highest pole intensity at the center. This implies that most of the crystals are aligned along two rotating axes (see “top view” in Figure f) with some aligned by symmetry . These results indicate that SP perovskite films have more uniform and oriented crystallites, in agreement with previous XRD and DLS results.…”

Enhanced Stability of Perovskite Solar Cells Incorporating Dopant‐Free Crystalline Spiro‐OMeTAD Layers by Vacuum Sublimation

“…Thus, it is expected for higher compactness of the Spiro-OMeTAD layer an enhanced performance in the protection of the perovskite to the atmospheric oxygen and moisture. [31] In addition, these materials usually become amorphous under the action of the electron beam, hampering their characterization by electron diffraction (selected area electron diffraction (SAED) or electron backscattered diffraction (EBSD)). The elucidation of the crystalline structure of organic nanocomposites and coatings is not straightforward by means of X-ray diffraction (XRD).…”

Controlling Polymorphism in Pharmaceutical Compounds Using Solution Shearing

“…To accomplish this, the incident angle of the X-ray beam must be carefully selected and tuned such that total internal reflection within the film occurs. 37 Too high of an angle will lead to penetration of the substrate while too low of a sample will reflect off the film without sampling a large area.…”

“…Compared to metallic and inorganic materials, the organic materials that are studied herein have fewer electrons to participate in the diffraction phenomenon contributing to low diffraction strength. 37 Using a synchrotron source of X-rays was necessary, due to the high flux and X-ray energy required to produce a reasonable signal.…”