No abstract

A hierarchical catalytic engine and morphology optimization lead to highly efficient micromotors that operate at a fuel concentration and speed close to those of biomolecular motors.

Viral capsid-like particles tiled with mosaic patches have attracted great attention as they imitate nature’s design to achieve advanced material properties and functions. Here, we develop a facile one-pot soft-template method to synthesize biomimetic gold capsid-like colloids with tunable particle size and surface roughness. Uniform submicron-to-micron-sized hollow gold colloidal particles are successfully achieved by using tannic acids as soft templates and reducing agents, which first self-assemble into spherical complex templates before the reduction of Au3+ ions via their surface hydroxyl groups. The surface roughness, the size, and the total number of the patches of the prepared gold particles are further tuned, utilizing a mechanism that offers morphology control by varying the number of surface hydroxyl groups participating in the reduction reactions. Among different capsid-like gold colloids, those possessing a rough surface display superior catalytic properties and show promising results as surface-enhanced Raman spectroscopy (SERS) solid substrates for detecting small organic molecules and biomimetic enzymes in a liquid phase for sensing biomolecules in real samples. These capsid-like gold colloids are also expected to find practical applications in delivery systems, electronics, and optics. We believe that our strategy of imitating nature’s design of capsid-like structures should also be used in the design and fabrication of other functional colloidal particles.

A good purification strategy for obtaining high-quality and low-cost perovskite QDs ink requires a complete removal of the impurities but with a minimal phase transition of QDs from the perovskite phases to the nonperovskite δ-phase. This pioneering work reports the electrochemical quantification on the phase transition level of CsPbI3 QDs in purification. Cyclic voltammetry of the purified QDs evidenced the formation of a new product in the purification process, which was demonstrated to be the undesired nonperovskite δ-phase by independent structural analysis. The developed electrochemical methodology further enabled the quantification of the extent of the phase transition of the QDs purified using different strategies by simply analyzing the charge associated with the relevant peaks and allowing optimization of the purification. The latter is of vital importance for commercialization and is an essential step for boosting their device performance.