Investigation of the size–property relationship in CuInS2 quantum dots

In this work we investigated fundamental properties of CuInS2 quantum dots in dependence of the particle size distribution (PSD). Size-selective precipitation (SSP) with acetone as poor solvent was performed as an adequate post-processing step. Our results provide deep insight into the correlation between particle size and various optical characteristics as bandgap energy, absorption and emission features and the broadness of the emission signal. These structure–property relationships are only achieved due to the unique combination of different analytical techniques. Our study reveals that the removal of 10 wt% of smallest particles from the feed results in an enhancement of the emission signal. This improvement is ascribed to a decreased quenching of the emission in larger particles. Our results reveal the impact of PSDs on the properties and the performance of an ensemble of multicomponent QDs and anticipate the high potential of controlling PSDs by well-developed post-processing

Ni-Co-O anodes for the alkaline oxygen evolution reaction: Multistage electrode optimization and plasma-assisted activity enhancement enabled by a coherent workflow

Improving the performance of oxygen evolution reaction (OER) catalysts through proper catalyst design and processing represents a critical step toward enhancing the efficiency of water electrolysis. While many studies focus on structure-activity relationships and mechanistic insights confined to a particular stage during the anode fabrication, an integrated approach covering all process steps is crucial to optimize performance-relevant properties such as composition, morphology, and electrode architecture. In this study, we demonstrate a comprehensive approach for developing Ni-Co-O anodes as a model system through the entire process chain. Starting from the initial powder characterization through operando to post-catalysis analyses, we first underpin the critical impact of catalyst ink optimization through solvent matrix screening, enabling high-quality electrode layers via ultrasonic spray coating on Ni plates. This enables us to uncover the effects of post nitrogen plasma treatment integrated into our coherent workflow yielding binder-free Ni-Co-O anode surfaces with enhanced redox reversibility, Fe uptake, porosity, and wettability. These improvements reduce the OER overpotential by ~43 mV at 100 mA/cm2 compared to untreated counterparts. The durable performance of these electrodes is further demonstrated in a single cell configuration. Our holistic approach from catalyst powder to post-mortem analysis highlights the benefits of a coherent anode development strategy employing plasma post-processing which is broadly applicable and easily transferable to other benchmark electrocatalysts

Anisotropic nanomaterials: structure, growth, assembly, and functions

Comprehensive knowledge over the shape of nanomaterials is a critical factor in designing devices with desired functions. Due to this reason, systematic efforts have been made to synthesize materials of diverse shape in the nanoscale regime. Anisotropic nanomaterials are a class of materials in which their properties are direction-dependent and more than one structural parameter is needed to describe them. Their unique and fine-tuned physical and chemical properties make them ideal candidates for devising new applications. In addition, the assembly of ordered one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) arrays of anisotropic nanoparticles brings novel properties into the resulting system, which would be entirely different from the properties of individual nanoparticles. This review presents an overview of current research in the area of anisotropic nanomaterials in general and noble metal nanoparticles in particular. We begin with an introduction to the advancements in this area followed by general aspects of the growth of anisotropic nanoparticles. Then we describe several important synthetic protocols for making anisotropic nanomaterials, followed by a summary of their assemblies, and conclude with major applications

Mechanochemically induced sulfur doping in ZnO via oxygen vacancy formation

Mechanochemically induced oxygen vacancy of ZnO is indispensable in order to control the level of sulfur doping quantitatively.</p