Probing Interfacial Stress of Single Pt nanocrystals and Oligocrystals via Multi-Reflection Bragg-CDI

A novel method called Mass Particle Compression (MPC) has been developed to achieve precise and uniform compressive deformation of nano- or micro-particles on a wafer. Combined with post-annealing, this method produces crystalline particles with varied orientations relative to their substrate, as well as oligocrystals composed of 2-3 grains. Oligocrystals impact properties like stress distribution and catalytic activity due to grain interactions. Their unique behavior, compared to single crystals or polycrystals, stems from the limited number of grain boundaries and orientations. In this study, we will use multi-reflection Bragg coherent diffraction imaging (BCDI), a state-of-tha-art crystal x-ray characterisation technique, to analyse particles produced via the MPC method, focusing on the strain and stress at the particle-substrate interface and at the grain boundaries. The goal is to provide a holistic understanding of the strain inside particles with high-energy singular surfaces.