Phase-separated polymer blend films are an important class of functional materials with numerous technological applications in solar cells, catalysis, and biotechnology. These technologies are underpinned by the precise control of phase separation at the nanometer length-scales, which is highly challenging to visualize using conventional analytical tools. Herein, we introduce tip-enhanced Raman spectroscopy (TERS), in combination with atomic force microscopy (AFM), confocal Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS), as a sensitive nanoanalytical method to determine lateral and vertical phase-separation in polystyrene (PS)-poly­(methyl methacrylate) (PMMA) polymer blend films. Correlative topographical, molecular, and elemental information reveals a vertical phase separation of the polymers within the top ca. 20 nm of the blend surface in addition to the lateral phase separation in the bulk. Furthermore, complementary TERS and XPS measurements reveal the presence of PMMA within 9.2 nm of the surface and PS at the subsurface of the polymer blend. This fundamental work establishes TERS as a powerful analytical tool for surface characterization of this important class of polymers at nanometer length scales.

The grafting of an iridium-aluminium precursor onto silica followed by thermal treatment under H2 yields small (<2 nm), narrowly distributed nanoparticles used as catalysts for methane H/D exchange. This Ir-Al/SiO2...

Tip-enhanced Raman spectroscopy (TERS) has emerged as a powerful analytical tool for nondestructive and label-free molecular characterization at the nanoscale. However, the influence of environmental factors and sample characteristics on the occurrence of spurious signals, enhancement of TERS signals, and longevity of TERS probes is not well understood yet. Herein, we present a detailed investigation of the influence of oxygen, humidity, and atmospheric carbon contaminants on scanning tunneling microscopy-TERS (STM-TERS) measurements of self-assembled monolayer systems in ambient and inert environments. Our results reveal a consistent increase of TERS signals, significant reduction of spurious signals, and drastically improved longevity of TERS probes in the inert environment. Additionally, sample characteristics such as molecular packing, chemisorption behavior, and hydrophilicity are found to have a direct impact on signal enhancement in the TERS measurements of molecular self-assembled monolayers (SAMs). The novel insights gained in this study are expected to pave the way for a more robust data analysis and improved experimental design in the future gap mode STM- and atomic force microscopy-TERS (AFM-TERS) studies.

We introduce a bio-inspired copper cubane-type water oxidation catalyst, and we track its transformations and electrocatalytically active species with comprehensive in situ and post-catalytic techniques.