Considered as a less hazardous piezoelectric material, potassium sodium niobate (KNN) has been in the fore of the search for replacement of lead (Pb) zirconate titanate for piezoelectrics applications. Here, we challenge the environmental credentials of KNN due to the presence of ~60 wt% Nb2O5, a substance much less toxic to humans than Pb oxide, but whose mining and extraction cause significant environmental damage.

Three-dimensional (3D) printing generates cellular architected metamaterials with complex geometries by introducing controlled porosity. Their ordered architecture, imitative from the hierarchical high-strength structure in nature, defines the mechanical properties that can be coupled with other properties such as the acoustic, thermal, or biologic response. Recent progress in the field of 3D architecture materials have advanced that enables for design of lightweight materials with high strength and stiffness at low densities. Applications of these materials have been identified in the fields of ultra-lightweight structures, thermal management, electrochemical devices, and high absorption capacity.

Self-assembly of multiferroic oxide composites by chemical and biochemical methodology is discussed. The approach involves covalently attaching organic functional groups or oligomeric DNA/RNA to the nanoparticles (NPs). The organic functional groups are only reactive toward functional groups located on different NPs. Using oligomeric DNA/RNA, one could program NPs to only interact with particles possessing complementary DNA/RNA. We have applied both concepts to the assembly of nanostructures with ferrites for the ferromagnetic phase and barium titanate for the ferroelectric phase. The assembled core–shell particles and superstructures obtained in a magnetic field show evidence for strong interactions between the magnetic and ferroelectric subsystems.

The diverse and fascinating properties of transition metal oxides stem from the strongly correlated electronic degrees of freedom; the scientific challenge and range of possible applications of these materials have caused fascination among physicists and materials scientists, thus capturing research efforts for nearly a century. Here, we focus on the binary V x O y and the ternary perovskite AVO3 and review the key aspects from the underlying physical framework and their basic properties, recent strides made in thin-film synthesis, to recent efforts to implement vanadium-based oxides for practical applications that augment existing technologies, which surpass limitations of conventional materials.

Recent advances in synchrotron based x-ray spectroscopy enable materials scientists to emanate fingerprints on important materials properties, e.g., electronic, optical, structural, and magnetic properties, in real-time and under nearly real-world conditions. This characterization in combination with optimized materials synthesis routes and tailored morphological properties could contribute greatly to the advances in solid-state electronics and renewable energy technologies. In connection to this, such perspective reflects the current materials research in the space of emerging energy technologies, namely photocatalysis, with a focus on transition metal oxides, mainly on the Fe2O3- and TiO2-based materials.

Polymer:fullerene nanoparticles (NPs) offer two key advantages over bulk heterojunction (BHJ) films for organic photovoltaics (OPVs), water-processability and potentially superior morphological control. Once an optimal active layer morphology is reached, maintaining this morphology at OPV operating temperatures is key to the lifetime of a device. Here we study the morphology of the PDPP-TNT (poly{3,6-dithiophene-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-naphthalene}):PC71BM ([6,6]-phenyl C71 butyric acid methyl ester) NP system and then compare the thermal stability of NP and BHJ films to the common poly(3-hexylthiophene) (P3HT): phenyl C61 butyric acid methyl ester (PC61BM) system. We find that material Tg plays a key role in the superior thermal stability of the PDPP-TNT:PC71BM system; whereas for the P3HT:PC61BM system, domain structure is critical.

In this study, we investigate spray pyrolysis as an approach to synthesis of tunnel structure sodium manganese oxide, as it is a cost-effective and scalable technology. The powders synthesized with Na/Mn ratio of 0.50 displayed a pure tunnel structure, and demonstrated the best electrochemical performance, with a discharge capacity of 115 mAh/g. The material also showed good cycleability and rate capability. Noticeable decay in performance was seen in materials with Na/Mn ratios other than 0.50, indicating that this material is sensitive to minor compositional deviations. This study has demonstrated that spray pyrolysis is a promising synthesis method for this material.

Phase predictions and characterizations on as-solidified septenary refractory high-entropy alloy, CrMoNbReTaVW, are presented. The simulated solidification process predicts a single body-centered-cubic (BCC) crystal structure with the tendency of compositional segregation. X-ray diffraction results confirm the “single-phase-like” BCC structure, while further experimental characterizations reveal the existence of multiple grains with significantly different compositions yet the same crystal structure and similar lattice parameters.

TiC/H13 nanocomposite parts were processed by selective laser melting using various energy densities; one part also underwent hot isostatic pressing (HIP). The effect of energy density and HIPing on densification, microstructure, and hardness were evaluated. It was found that the densification was not largely affected by the energy density, but the HIP-treated sample displayed a large improvement in relative density. With increasing energy density, the microstructures showed high levels of dispersion of nanoparticles, while HIP treatment coarsened the microstructure and induced agglomeration. Both HIP treatment and increased energy density lowered hardness markedly; this was likely due to annealing effects.

The novel Three-dimensional rambutan-like NiCo2O4 microspheres have been successfully coated onto surface of carbon nanofibers (CNFs) to form NiCo2O4–CNFs hybrids. The composition and microstructure of NiCo2O4–CNFs were characterized by the field-emission scanning electronmicroscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, and x-ray diffractometer. The obtained NiCo2O4–CNFs exhibited a specific capacity of 160 mAh/g at 1 mA/cm2 in 2 M potassium hydroxide aqueous solution. The specific capacity gradually increases with the increasing of cycles; and after 3000 cycles, the specific capacity still can be remained over 90%.