In this Review, we aim to provide an updated summary of the research related to hollow micro- and nanostructures, covering both their synthesis and their applications. After a brief introduction to the definition and classification of the hollow micro-/nanostructures, we discuss various synthetic strategies that can be grouped into three major categories, including hard templating, soft templating, and self-templating synthesis. For both hard and soft templating strategies, we focus on how different types of templates are generated and then used for creating hollow structures. At the end of each section, the structural and morphological control over the product is discussed. For the self-templating strategy, we survey a number of unconventional synthetic methods, such as surface-protected etching, Ostwald ripening, the Kirkendall effect, and galvanic replacement. We then discuss the unique properties and niche applications of the hollow structures in diverse fields, including micro-/nanocontainers and rea...

Synthesis, Properties, and Applications of Hollow Micro-/Nanostructures

Giant and isotropic magnetoresistance as huge as −53% was observed in magnetic manganese oxide La0.72Ca0.25MnOz films with an intrinsic antiferromagnetic spin structure. We ascribe this magnetoresistance to spin‐dependent electron scattering due to spin canting of the manganese oxide.

31p-S-4 Giant Magnetoresistance in Magnetic Manganese Oxide with Intrinsic Antiferromagnetic Spin Structure

Photocorrosion stable WO3 nanowire arrays are synthesized by a solvothermal technique on fluorine-doped tin oxide coated glass. WO3 morphologies of hexagonal and monoclinic structure, ranging from nanowire to nanoflake arrays, are tailored by adjusting solution composition with growth along the (001) direction. Photoelectrochemical measurements of illustrative films show incident photon-to-current conversion efficiencies higher than 60% at 400 nm with a photocurrent of 1.43 mA/cm2 under AM 1.5G illumination. Our solvothermal film growth technique offers an exciting opportunity for growth of one-dimensional metal oxide nanostructures with practical application in photoelectrochemical energy conversion.

Vertically Aligned WO3 Nanowire Arrays Grown Directly on Transparent Conducting Oxide Coated Glass: Synthesis and Photoelectrochemical Properties

https://physics.ucf.edu/%7Elc/MEE-Final.pdf

Novel hydrogen gas sensor based on single ZnO nanorod

Diameter-controlled Growth of Single-crystalline In2O3 Nanowires and Their Electronic Properties

Fabrication of nanowires of multicomponent oxides: Review of recent advances

Enhanced ferromagnetic transition temperature in nanocrystalline lanthanum calcium manganese oxide (La0.67Ca0.33MnO3)

We report fabrication of array of crystalline nanowires (average diameter of 65 nm) of colossal magnetoresistive oxide La0.67Ca0.33MnO3 (LCMO, x50.33) within anodized alumina templates by filling the pores with a sol that allows formation of LCMO phase at the relatively low temperature of 600 °C. The crystalline nanowires with correct stoichiometry stabilize in the orthorhombic phase at room temperature. The nanowires are ferromagnetic at room temperature and exhibit enhanced ferromagnetic transition temperature well in excess of 300 K, which is substantially higher than that of single crystalline LCMO. This enhancement we attribute to the size induced lattice contraction in the nanowires.

/pdf/fabrication-of-ordered-array-of-nanowires-of-la0-67ca0-5ffxua6fx0.pdf

Fabrication of ordered array of nanowires of La0.67Ca0.33MnO3 (x=0.33) in alumina templates with enhanced ferromagnetic transition temperature

We report the growth of oriented nanowires of manganites within the pores of anodic alumina (AAO) templates. The processing of stoichiometric nanowires of $La_{0.67}Sr_{0.33}MnO_3 (LSMO)$ at relatively low temperatures (870 K) is greatly aided by the linear chain polymer cation complex formed by ethylene glycol. The nanowires were found to grow preferentially along the $\langle110\rangle$ direction of cubic LSMO. The growth of oriented nanowires was achieved by: (a) electrostatically confining the sol particles to the core regions of the cylindrical pores of the template—this avoids heterogeneous nucleation of LSMO on amorphous pore walls and (b) introducing a polymer matrix that serves as a backbone structure to the growing crystallites—this facilitates reorientation of the grains during heat treatment. The nanowires are ferromagnetic at room temperature and exhibit a ferromagnetic transition temperature $(T_c)$ of 370 K.

http://iopscience.iop.org/article/10.1088/0957-4484/15/9/034/pdf

Growth of an ordered array of oriented manganite nanowires in alumina templates

We report a simple modified polymeric precursor route for the synthesis of highly crystalline and homogenous nanoparticles of lanthanum calcium manganese oxide (LCMO). The LCMO phase formation was studied by thermal analysis, x-ray powder diffraction, and infrared spectroscopy at different stages of heating. These nanocrystallites (average particle size of 30 nm) possess ferromagnetic-paramagnetic transition temperature (Tc) of 300 K, nearly 50 K higher than that of a single crystal. The Rietveld analysis of the powder x-ray diffraction data of the nanopowders reveals significant lattice contraction and reduction in unit cell anisotropy-these structural changes are correlated to the enhancement in Tc.

Low-temperature polymer precursor-based synthesis of nanocrystalline particles of lanthanum calcium manganese oxide (La0.67Ca0.33MnO3) with enhanced ferromagnetic transition temperature

K. Shantha Shankar

Papers

Fabrication of nanowires of multicomponent oxides: Review of recent advances

Enhanced ferromagnetic transition temperature in nanocrystalline lanthanum calcium manganese oxide (La0.67Ca0.33MnO3)

Fabrication of ordered array of nanowires of La0.67Ca0.33MnO3 (x=0.33) in alumina templates with enhanced ferromagnetic transition temperature

Growth of an ordered array of oriented manganite nanowires in alumina templates

Low-temperature polymer precursor-based synthesis of nanocrystalline particles of lanthanum calcium manganese oxide (La0.67Ca0.33MnO3) with enhanced ferromagnetic transition temperature