Self-assembled vertical heteroepitaxial nanostructures (VHN) in the complex oxide field have fascinated scientists for decades because they provide degrees of freedom to explore in condensed matter physics and design-coupled multifunctionlities. Recently, of particular interest is the perovskite-spinel-based VHN, covering a wide spectrum of promising applications. In this review, fabrication of VHN, their growth mechanism, control, and resulting novel multifunctionalities are discussed thoroughly, providing researchers a comprehensive blueprint to construct promising VHN. Following the fabrication section, the state-of-the-art design concepts for multifunctionalities are proposed and reviewed by suitable examples. By summarizing the outlook of this field, we are excitedly expecting this field to rise with significant contributions ranging from scientific value to practical applications in the foreseeable future.

The optoelectronic and thermal properties of conjugated polymers are frequently tuned via direct synthetic modification of the conjugated repeat unit. It is also well known that these properties are inherently tied to the crystal structure, a factor which is difficult to predict upon slight chemical modification. We show that the crystal structure of random copolymers of 3-alkylthiophenes can be controlled, which in turn affects the optoelectronic properties. Furthermore, we show that the melting transitions smoothly vary between that of the two homopolymers. As such, the composition of copolymers is a convenient handle to predictably control the thermal properties, crystalline morphology, and optoelectronic properties simultaneously.

We have used phase-separated poly(3-hexyltiophene) (P3HT)/poly(L-lactic acid) (PLLA) blends to fabricate low-voltage ion-modulated transistors on a rough paper substrate. The semiconductor and insulator are mixed together in a solution and spin casted onto the paper substrate. Owing to their different solubilities and surface energies the P3HT and PLLA will phase separate vertically during the spinning process creating a thin layer of semiconductor on top of the insulator. This thin semiconductor layer, difficult to achieve by other means on an absorbing paper substrate, creates faster ion-modulated transistors. Using this approach we have created ring-oscillators on paper oscillating at 5 Hz.

With multiple elements mixed at equal or near-equal molar ratios, the emerging, high-entropy alloys (HEAs), also named multi-principal elements alloys (MEAs), have posed tremendous challenges to materials scientists and physicists, e.g., how to predict high-entropy phase formation and design alloys. In this paper, we propose some guidelines in predicting phase formation, using thermodynamic and topological parameters of the constituent elements. This guideline together with the existing ones will pave the way toward the composition design of MEAs and HEAs, as well as property optimization based on the composition–structure–property relationship.

Using detailed information on the spectrum of shear transformation dynamics previously obtained from low-strain, quasi-static anelastic relaxation in a metallic glass, the corresponding response to a cyclic force is calculated, and prevailing analysis approaches are evaluated. It is shown that the time–temperature superposition principle does not resolve the distribution of activation energies for shear transformations. The distribution of shear transformation zone sizes explains the microscopic mechanisms of both slow (α) and fast (β) relaxations, and the fact that the former are irreversible. These results suggest the need to re-evaluate past interpretations of dynamic behavior of glasses.

We previously demonstrated that TiOx/Al2O3 nanolaminates (TAO NL) exhibit abnormally high-dielectric constant k (800–1000), due to Maxwell–Wagner polarization, via charge accumulation at insulating Al2O3/semiconducting TiOx interfaces. Here, we report TAO NL dielectric properties related to TiOx phase change in TiOx (0.9 nm)/Al2O3 (0.1 nm) NL. High-resolution transmission electron microscopy shows amorphous TiOx phase change to crystalline anatase TiO2 due to free-energy minimization. The phase change induce reduction in leakage current and dielectric loss (J = 10−2 to 10−4 A/cm2, tan δ = 10 to 10−1), still with k ~ 600 up to MHz, compared to amorphous TAO NLs.

Titanium oxide (TiO2) nanoparticles (NPs) were doped with vanadium using a novel, facile, and inexpensive method. The TiO2 NPs were dispersed in a vanadyl oxalate solution prepared by dissolving vanadium pentoxide (V2O5) in oxalic acid. A short heat treatment at 400 °C applied to the dried mixture resulted in the doping of TiO2 with a net measured decrease of its band gap by about 0.5 eV, making this important semiconductor material usable in the visible light spectrum.

A simple method was used to electrodeposit a metallic coating on vertically aligned carbon nanotube (CNT) arrays, herein referred to as turfs, creating an open cell, core–shell foam. The foam exhibited highly elastic behavior, approaching the amount of elastic recovery in compression of a pure CNT turf. The turfs were pre-treated with an acid bath, and were electroplated at low voltages with nickel and copper. This simple method can be expanded to prepare a large variety of nanostructured foams (e.g., the carbon support can be changed, the metal deposited selected and its thickness controlled) while maintaining their mechanical robustness.