As one of next-generation semiconductors, hybrid halide perovskites with tailorable optoelectronic properties are promising for photovoltaics, lighting, and displaying. This tunability lies on variable crystal structures, wherein the spatial arrangement of halide octahedra is essential to determine the assembly behavior and materials properties. Herein, we report to manipulate their assembling behavior and crystal dimensionality by locally collective hydrogen bonding effects. Specifically, a unique urea-amide cation is employed to form corrugated 1D crystals by interacting with bromide atoms in lead octahedra via multiple hydrogen bonds. Further tuning the stoichiometry, cations are bonded with water molecules to create a larger spacer that isolates individual lead bromide octahedra. It leads to zero-dimension (0D) single crystals, which exhibit broadband ‘warm’ white emission with photoluminescence quantum efficiency 5 times higher than 1D counterpart. This work suggests a feasible strategy to modulate the connectivity of octahedra and consequent crystal dimensionality for the enhancement of their optoelectronic properties.

Konjac glucomannan (KGM) has attracted extensive attention because of its biodegradable, non-toxic, harmless, and biocompatible features. Its gelation performance is one of its most significant characteristics and enables wide applications of KGM gels in food, chemical, pharmaceutical, materials, and other fields. Herein, different preparation methods of KGM gels and their microstructures were reviewed. In addition, KGM applications have been theoretically modeled for future uses.

We investigated the segmental mobility distribution at the poly(methyl methacrylate) film surface within the depth of 9.0 nm, by measuring the surface reorganization of fluorinated tracer-labeled PMMA using three different surface-sensitive techniques with various analytical depth capabilities, including contact angle measurements, sum frequency generation (SFG) vibrational spectra and angle-resolved X-ray photoelectron spectroscopy (XPS). The onset temperature of fluorinated chain end reorganization (T onset ) at various depths was identified and is shown to depend on the sampling depth of the techniques. The T onset was verified to be related to the segmental relaxation of PMMA. Plotting the T onset against the sensing depth of the corresponding technique, the distribution of surface T onset within a 9.0 nm depth was obtained. An approximately 2.4 nm surface layer with depth-independent T onset was found, below which the T onset increased with increasing depth. The depth profile of T onset effectively divides a film into three layers: a "surface layer" with Arrhenius dynamics on the uppermost film surface, a "gradient region" layer underneath the top layer transporting "liquid-like" dynamics into the internal film, and the remaining bulk layer. This observed depth profile of the surface dynamics may suggest that the polymer chains near the surface adopt an oblate conformation and have lowered entanglements.

A series of self-complementary ureido pyrimidinedione (UPy) derivatives modified with different aurophilic anchoring groups were synthesized. Their electron transport properties through the quadruple hydrogen bonds in apolar solvent were probed employing the scanning tunneling microscopy break junction (STMBJ) technique. The molecule terminated with a thiol shows the optimal electron transport properties, with a statistical conductance value that approaches 10(-3)  G0 . The (1) H NMR spectra and control experiments verify the formation of quadruple hydrogen bonds, which can be effectively modulated by the polarity of the solvent environment. These findings provide a new design strategy for supramolecular circuit elements in molecular electronics.