Facile synthesis of the three-dimensional flower-like ZnFe2O4@MoS2 composite with heterogeneous interfaces as a high-efficiency absorber.

Lightweight and high-efficiency microwave absorbers are determined by structure and composition of materials. In this research, a novel core-shell ZnFe2O4@MoS2 composite with a flower-like heterostructure was synthesized successfully by a facile hydrothermal process. The unique 3D heterostructure (porous ZnFe2O4 and MoS2 nanosheets as core and outer shells, respectively) endows the synthesized sample with high-efficiency electromagnetic wave absorption performance. The exploration of microwave absorption properties reveals that the maximum reflection loss displayed by the ZnFe2O4@MoS2 composite is up to -61.8 dB at 9.5 GHz with a filler content of 20 wt%, and the corresponding effective bandwidth (RL exceeding -10 dB) achieves 5.8 GHz (from 7.2 to 13 GHz). The enhanced microwave absorption performance is benefitted by the porous core-shell structure, intense interfacial polarization, multiple reflections, matched impedance and favorable synergistic effect between ZnFe2O4 core and MoS2 shell. Consequently, this strategy provides inspiration for the design of novel microwave absorber with high-performance.

A redox-controlled electrolyte for plasmonic enhanced dye-sensitized solar cells.

Plasmonic enhanced dye-sensitized solar cells (DSSCs) with metallic nanostructures suffer from corrosion problems, especially with the presence of the iodine/triiodide redox couple in the electrolyte. Herein, we introduce an alternative approach by compensating the corrosion with a modified liquid electrolyte. In contrast to the existing method of surface preservation for plasmonic nanostructures, the redox-controlled electrolyte (RCE) contains iodoaurate intermediates, i.e. gold(i) diiodide (AuI2-) and gold(iii) tetraiodide (AuI4-) with optimal concentrations, such that these intermediates are readily reduced to gold nanoparticles during the operation of DSSCs. As corrosion and redeposition of gold occur simultaneously, it effectively provides corrosion compensation to the plasmonic gold nanostructures embedded in the photoanode. Cycling tests of the specific amount of gold contents in the RCE of DSSCs support the fact that the dissolution and deposition of gold are reversible and repeatable. This gold deposition on the TiO2 photoanode results in forming a Schottky barrier (SB) at the metal-semiconductor interface and effectively inhibits the recombination of electron-hole pairs. Therefore, the RCE increases the short-circuit current, amplifies the open-circuit voltage, and reduces the impedance of the TiO2/dye interface. The power conversion efficiency of DSSCs was improved by 57% after incorporating the RCE.

Highly ductile UV-shielding polymer composites with boron nitride nanospheres as fillers.

Polymer composites with enhanced mechanical, thermal or optical performance usually suffer from poor ductility induced by confined mobility of polymer chains. Herein, highly ductile UV-shielding polymer composites are successfully fabricated. Boron nitride (BN) materials, with a wide band gap of around ∼6.0 eV, are used as fillers to achieve the remarkably improved UV-shielding performance of a polymer matrix. In addition, it is found that spherical morphology BN as a filler can keep the excellent ductility of the composites. For a comparison, it is demonstrated that traditional fillers, including conventional BN powders can achieve the similar UV-shielding performance but dramatically decrease the composite ductility. The mechanism behind this phenomenon is believed to be lubricant effects of BN nanospheres for sliding of polymer chains, which is in consistent with the thermal analyses. This study provides a new design to fabricate UV-shielding composite films with well-preserved ductility.

Solvent-free fabrication of thermally conductive insulating epoxy composites with boron nitride nanoplatelets as fillers.

A solvent-free method for the fabrication of thermally conductive epoxy-boron nitride (BN) nanoplatelet composite material is developed in this study. By this method, polymer composites with nearly any filler fractions can be easily fabricated. The maximum thermal conductivity reaches 5.24 W/mK, which is 1,600% improvement in comparison with that of pristine epoxy material. In addition, the as-fabricated samples exhibit excellent overall performances with great mechanical property and thermal stability well preserved.