Biomolecules can form micro- and nanoscale structures with unique physicochemical properties. These structures tend to grow randomly in solution or on a substrate, and the lack of orientation control stems from a limited understanding of the self-assembly process, hindering their applications. Here, we achieve aligned, uniform nanorod arrays of aromatic amino acids via an electric-field-assisted physical vapor deposition process. The electric driving force and non-covalent intermolecular interactions work synergistically in biomolecular self-assembly. The vapor-deposition angle controls the stacking direction of tyrosine, phenylalanine, and levodopa, and a dynamic transition from vertical columnar crystals to horizontal needle-like epitaxial growth is observed. The good mechanical properties and piezoelectric response enable the fabrication of piezoelectric nanogenerators for environmental energy harvesting. The present work provides a new direction for the controlled growth of smart biomaterials and promotes their practical applications.

The synergistic interaction of different components in heteronanocrystals induces interfacial phenomena and novel functionalities. Nonetheless, effective technologies to design and fabricate heteronanocrystals with materials on demand are still missing. Rich heterostructures in a copper patina are known to form at room temperature and under atmospheric pressure. The redox process of copper tarnish inspired the discovery of a simple strategy to achieve heteronanocrystals that contained elements from group 3–11 and group 14–16. The interface redox-induced method is self-regulating at ambient conditions and applicable for metal, semiconductor, and dielectric materials. The enhanced interface bonding endows the heteronanocrystals with outstanding stability and catalytic performance, while the modular approach enables the design and fabrication of heteronanocrystals with intended materials to meet different purposes.

The low separation efficiency of the photogenerated carrier and the poor activity of the surface redox reaction are the main barrier to further improvement of photocatalytic materials. To address these issues, introducing spin-polarized electrons in single-component photocatalytic materials emerged as a promising approach. However, the decreased redox ability of photocarriers in these materials becomes a new challenge. Herein, we mitigate this challenge with a carbon nitride sheet (CNs)/graphene nanoribbon (GNR) composite material that has a van der Waals heterostructures (vdWHs) and spin-polarized electron properties. Experimental results and theoretical calculations show that the heterostructure has a strong redox ability, high carrier-separation efficiency, and enhanced surface catalytic reaction. Consequently, the mixed-dimensional CNs/GNR vdWHs exhibit remarkable performance for H₂ and O₂ generation as well as CO₂ production under visible-light irradiation without any cocatalyst. The spin-polarized vdWHs discovered in this study revealed a new type of photocatalytic materials and advanced the development of spintronics and photocatalysis.

Ferroelectric thin/thick films with large electrocaloric (EC) effect are critical for solid state cooling technologies. Here, large positive EC effects with two EC peaks in a broad temperature range (~100 K) were obtained in 0.95Pb_0.92La_0.08(Zr_0.70Ti_0.30)_0.98O₃-0.05BiFeO₃ (BFOLa-codoped PZT) epitaxial thin films deposited on the (100), (110) and (111) oriented SrTiO₃ (STO) substrates by a sol-gel method. The thin film deposited on the (111) oriented STO substrate exhibited a stronger EC effect (~20.6 K at 1956 kV/cm) near room temperature. However, the thin films deposited on the (100) and (110) oriented STO substrates exhibited a stronger EC effect (~18.8 K at 1852 kV/cm and ~20.8 K at 1230 kV/cm, respectively) around the peak of the dielectric permittivity (T_m, ~375 K). Particularly, as the direction of the applied electric field was switched (E < 0), the ΔT of the (100)-oriented thin films around T_m was enhanced significantly from 18.8 K to 38.1 K. The self-induced-poling during the preparing process maybe plays a key role on the magic phenomenon. It can be concluded that the BFOLa-codoped PZT epitaxial thin films are promising candidates for application in the next solid-state cooling devices.