Jian Yao Zheng

ZnO Hollow Spheres with Double‐Yolk Egg Structure for High‐Performance Photocatalysts and Photodetectors

Inspired by opening soft drink cans, a one-pot method to prepare ZnO hollow spheres with double-yolk egg (DEH) architectures is developed. The bubble-assisted Ostwald ripening is proposed for the formation of these novel structures. Uniqueness of DEHs morphology led to greatly enhanced photocatalytic activity and photodetector performance. The newly developed synthetic concept and the obtained novel morphologies should pave the way towards the design and fabrication of other similar materials with enhanced properties for microelectronics, optoelectronics, and other applications.

Wire-on-Wire Growth of Fluorescent Organic Heterojunctions

Dendritic organic heterojunctions with aluminum tris(8-hydroxyquinoline) (Alq(3)) microwire trunks and 1,5-diaminoanthraquinone (DAAQ) nanowire branches were prepared by a two-step growth process. The prefabricated Alq(3) microwires act as nucleation centers for site-specific secondary vapor growth of DAAQ nanowires, resulting in the unique dendritic heterostructures. When the trunk was excited with a focused laser beam, emitted light of various colors was simultaneously channeled from the branched nanowires via both waveguiding and energy transfer. The intensity of the out-coupled emissions was modulated effectively by changing the polarization of the incident light.

Self-modulated white light outcoupling in doped organic nanowire waveguides via the fluctuations of singlet and triplet excitons during propagation.

polymers, [ 5 ] and small organic molecules [ 6–11 ] are widely investigated for their applications in optoelectronic communications and sensors. [ 12 , 13 ] The semiconductor and metal waveguides are based on the propagation of photons and surface plasmon polaritons (SPPs), respectively. Very recently, it was proposed that organic waveguide materials work with a distinct principle, i.e., exciton polaritons (EPs) formed by the strong coupling between Frenkel excitons and photons play an essential role in organic optical waveguides. [ 14 ] Due to the photon–exciton coupling, EPs show excellent propagation properties compared with uncoupled light. [ 15 ] Moreover, the participation of excitons might introduce interesting electron and energy processes during propagation, which are helpful for the realization of novel waveguide behaviors. Excitons can be converted between two organic compounds accompanied by energy transfers, through which white light emissions (WLEs) can be achieved. [ 16 ] As devices are being designed on ever diminishing scales, WLE sub-wavelength waveguides are desired as small white light generators in micro-photonic circuits. In general, white lights are generated by the incomplete quenching of donor emissions and the color mixing of donors and acceptors at given doping ratios by either singlet–singlet (SSET), [ 17 ] or triplet–triplet energy transfer (TTET). [ 18 ] However, this strategy is greatly limited in constructing single nanowire WLE waveguides in that the color is supersensitive to the doping ratio, and a slight change of acceptor content by environmental heating, oxidation, or light irradiation in practical applications will signifi cantly infl uence the white light output. [ 19 ] Inspired by the voltage stabilizer in electric circuits, herein we demonstrate a kind of optical modulator based on doped organic nanowire waveguides, which can output constant white light from the wire terminus, despite the doping contents. The modulation was realized by the fl uctuations of singlet and triplet excitons during EP propagation as

A facile synthesis and lithium storage properties of Co3O4–C hybrid core-shell and hollow spheres

We report a facile route to synthesize Co3O4–C hybrid core-shell and hollow spheres with porous structures. Based on the results of the numerous characterization methods used, the ligand exchange etching mechanism is proposed to explain the formation of these two structures. Evaluated as an anode material in lithium-ion batteries (LIBs), both core-shell and hollow submicrospheres manifest excellent cycling performance. This feature may be attributed to the uniform distribution of amorphous carbon and structural characteristics of these submicrospheres. Moreover, the superior reversible capacity of the core-shell spheres is 825 mA h g−1 over 40 cycles (the theoretical capacity value: ∼890 mA h g−1), resulting from a higher void-space-utilizing rate and the right accommodation of the volume change during the charge process. Despite various reported methods, this novel strategy may provide new thoughts to prepare other hollow structured materials.

Optical Modulation Based on Direct Photon‐Plasmon Coupling in Organic/Metal Nanowire Heterojunctions

Surface plasmon polaritons (SPPs) can be launched with an organic nanowire that serves as both light source and dielectric waveguide in a single organic/metal nanowire heterojunction. Efficient modulation of the output signals from the silver tip can be achieved via the alternation of incident polarizations, which is further used to design and realize prototypical photonic-plasmonic logic devices. These findings are essential for incorporating plasmonic waveguides as practical components into hybrid high-capacity photonic circuits.

Electrogenerated Chemiluminescence of Metal–Organic Complex Nanowires: Reduced Graphene Oxide Enhancement and Biosensing Application

Electrogenerated chemiluminescence (ECL) is the production of light from the high-energy electron-transfer reaction between electrogenerated species. [ 1 ] As a valuable detection method, ECL is becoming more recognized in analytical chemistry due to its versatility, high stability, low background signal, and good temporal and spatial control. [ 2–5 ] Regenerable ECL sensors have been extensively studied, because they can reduce the consumption of reagents and simplify the experimental design. [ 6–12 ]

Hydrogen Peroxide Vapor Sensing with Organic Core/ Sheath Nanowire Optical Waveguides

Continuing efforts have been focused on detecting H 2 O 2 by different strategies such as infrared/Raman spectroscopy, [ 4 ] mass spectrometry, [ 5 ] electrochemical method, [ 6 ] colorimetric [ 7 ] and fl uorimetric detection. [ 8 ] Generally these methods either require expensive bulky equipment and tedious sample preparation, or have poor selectivity and limits of detection. Therefore, the development of contrast agents that allow the expedient detection of H 2 O 2 at low concentration is in demand. Peroxalate ester and its derivatives are typical chemiluminogenic compounds highly sensitive to H 2 O 2 . [ 9 ] The reaction between peroxalate ester groups and H 2 O 2 can generate a high-energy intermediate that may transfer energy to the fl uorescent dye, resulting in effi cient luminescence. This has been proved to be a promising strategy for the expedient and sensitive detecting of H 2 O 2 . [ 1 , 10 ]

Cubic nickel frames: one-pot synthesis, magnetic properties and application in water treatment

Cubic nickel frames were fabricated through an etchant-assisted solution method. This procedure brought into play the synergetic effects of oriented attachment, Ostwald-ripening and facet-selective etching. The obtained products showed an excellent ability to remove heavy metal ions in water treatment. The peculiar structures of these frames make them potentially useful in many other applications.