Xiujie Hu

Synthesis and electromagnetic, microwave absorbing properties of core-shell Fe3O4-poly(3, 4-ethylenedioxythiophene) microspheres.

Highly regulated core-shell Fe(3)O(4)-poly(3, 4-ethylenedioxythiophene) (PEDOT) microspheres were successfully synthesized by a two-step method in the presence of polyvinyl alcohol (PVA) and p-toluenesulfonic acid (p-TSA). And their morphology, microstructure, electromagnetic and microwave absorbing properties were subsequently characterized. By simply adjusting the molar ratio of 3, 4-ethylenedioxythiophene (EDOT) to Fe(3)O(4) (represented by (EDOT)/(Fe(3)O(4))), the thickness of the polymer shell can be tuned from tens to hundreds of nanometers. Moreover, it was found that the composite exhibited excellent microwave absorbing property with a minimum reflection loss (RL) of about -30 dB at 9.5 GHz with a (EDOT)/(Fe(3)O(4)) ratio of 20.

Preparation of self-supporting hierarchical nanostructured anatase/rutile composite TiO2 film

Via the combination of an electrospinning method with a hydrothermal reaction, a large-scale cedar-like hierarchical nanostructured TiO(2) film with an anatase/rutile composite phase was fabricated.

Low Ag-doped titanium dioxide nanosheet films with outstanding antimicrobial property.

Novel Ag-doped TiO(2) perpendicular nanosheet films were synthesized by a mild solvothermal method. The width of TiO(2) nanosheets was facilely tuned by controlling reaction time, and furthermore the pattern of TiO(2) nanosheets was easily obtained via predesigned seed layer. The antibacterial effects of Ag-TiO(2) thin films against Escherichia coli and Staphylococcus aureus were examined by film attachment method. The coating films showed excellent performance in killing bacteria under UV light. Moreover, the potent antimicrobial ability of the film was well-sustained even in the dark environment.

Controlled fabrication of highly conductive three-dimensional flowerlike poly (3,4-ethylenedioxythiophene) nanostructures

Poly(3,4-ethylenedioxythiophene) (PEDOT) with three-dimensional (3D) flowerlike nanostructures was fabricated by chemical oxidation polymerization in a ternary phase system, which was composed of the surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT), aqueous FeCl3 solution and p-xylene. This kind of 3D flowerlike PEDOT formed by nanofibers was prepared by controlling the molar ratio of water (used to dissolve FeCl3) to the surfactant, AOT. This molar ratio is defined as N which equals nH2O/nAOT. In particular, both the conductivity and specific surface area increased with the molar ratio, N, increasing. The room temperature conductivity of the synthesized PEDOT reached a relative high value of 137 S cm−1. Moreover, the novel 3D flowerlike nanostructures endow a high specific surface area of around 46 m2 g−1. The measurements of UV-visible spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS) indicate that the doping level played a key role in improving conductivity of PEDOT. This study is significant to the potential applications of PEDOT on supercapacitors, sensors, actuators, transistors, and so on.

In situ bifunctionalized carbon dots with boronic acid and amino groups for ultrasensitive dopamine detection

In this paper, in situ bifunctionalized carbon dots (B-N-CDs) with boronic acid and amino groups were prepared by a simple hydrothermal method using 3-aminophenylboronic acid as the sole precursor. The high quantum yield of B-N-CDs is as high as 67%, leading to fluorescence emission observed even under daylight excitation. The B-N-CDs exhibited obvious fluorescence enhancement to trace dopamine in the range of 1 pM to 1 μM with a detection limit of 0.1 pM (S/N = 3), which is two orders of magnitude more sensitive than that of present fluorescent sensors. The excellent sensing performance is based on the interaction of two functional groups with DA. This dopamine probe owned advantages of high sensitivity, superior selectivity, good reproducibility and simplicity. Moreover, the analytical reliability of this dopamine sensor was demonstrated in human serum samples.

Flexible supercapacitors based on 3D conductive network electrodes of poly(3,4-ethylenedioxythiophene)/non-woven fabric composites

We design a flexible supercapacitor with poly(3,4-ethylenedioxythiophene) nanowire-coated non-woven fabrics (PEDOT/NW) as the electrode material via a simple and low-cost chemical polymerization synthesis. PEDOT nanowires depositing on non-woven fabrics form a conductively and mechanically robust composite that is utilized directly as an electrode without introducing organic binders or conducting additives. The PEDOT/NW electrodes are characterized by scanning electron microscopy (SEM) that confirms the porous morphology of PEDOT/NW at the nanoscale. The capacitive characteristics of the supercapacitor are evaluated by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy techniques. The PEDOT/NW composites afford a high-efficient and stable electrode for a supercapacitor showing high specific capacitance of 169 F g−1 and excellent energy density of 21.1 W h kg−1 as well as good long-term cycling stability with 90% specific capacitance retained after 1000 cycles. Therefore, this conductively porous PEDOT/NW electrode holds considerable promise as a flexible, low-cost and high-efficient electrode material.

A facile process to produce highly conductive poly(3,4-ethylenedioxythiophene) films for ITO-free flexible OLED devices

A facile vapor phase polymerization (VPP) method is carried out to fabricate highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) flexible films with a low concentration FeCl3 ethanol solution as the oxidant, without high temperature, vacuum conditions and additives. Three kinds of PEDOT morphologies (square-like, flower-like and flat) can be observed on the surface of the films and the appearance of the square-like and flower-like structures does not affect the transparency of the films. A ca. 1500 S cm−1 film conductivity is achieved and after dipping in a H2SO4 solution, the conductivity significantly increases to ca. 2200 S cm−1 with a sheet resistance down to 50 Ω □−1 and a transparency in the visible spectrum of >80% at 90 nm thickness. In addition, a simple ITO-free flexible OLED device was designed with a VPP–PEDOT film as the anode which was able to maintain a stable luminance after various kinds of bending and showed the feasibility of substituting PEDOT for the ITO layer in flexible OLED devices. The facile way offers an effective and convenient strategy to fabricate highly conductive PEDOT films and represents a significant step forward in the manufacture of flexible OLED devices and flexible displays in the rapidly growing organic electronics arena.

Multimodal bioimaging based on gold nanorod and carbon dot nanohybrids as a novel tool for atherosclerosis detection

Advanced biocompatible and robust platforms equipped with diverse properties are highly required in biomedical imaging applications for the early detection of atherosclerotic vascular disease and cancers. Designing nanohybrids composed of noble metals and fluorescent materials is a new way to perform multimodal imaging to overcome the limitations of single-modality counterparts. Herein, we propose the novel design of a multimodal contrast agent; namely, an enhanced nanohybrid comprising gold nanorods (GNRs) and carbon dots (CDs) with silica (SiO2) as a bridge. The nanohybrid (GNR@SiO2@CD) construction is based on covalent bonding between SiO2 and the silane-functionalized CDs, which links the GNRs with the CDs to form typical core–shell units. The novel structure not only retains and even highly improves the optical properties of the GNRs and CDs, but also possesses superior imaging performance in both diffusion reflection (DR) and fluorescence lifetime imaging microscopy (FLIM) measurements compared with bare GNRs or fluorescence dyes and CDs. The superior bioimaging properties of the GNR@SiO2@CD nanohybrids were successfully exploited for in vitro DR and FLIM measurements of macrophages within tissue-like phantoms, paving the way toward a theranostic contrast agent for atherosclerosis and cancer.

Tuning PANI nanostructure by driving force for diverse capacitance performance

PANI with controllable nanostructures, i.e., helixes, nanofibers and nanoparticles, were obtained through a self-assembly process during emulsion polymerization by simply regulating the stirring. PANI helixes and nanofibers exhibit better capacitance performance than PANI nanoparticles due to higher crystallinity, regularity and conductivity of PANI in the 1D nanostructures.

Fabrication of PEDOT/PSS-ZnO nanowire by self-assembly method under vacuum condition

In this paper, cable-like PEDOT/PSS-ZnO nanowires are successfully fabricated under vacuum condition by self-assembly of the PEDOT/PSS-ZnO composite initially prepared via sol-gel method. Characterized by TEM and EDX, the nanowire is found to have a polycrystalline ZnO inner core that is sheathed by the PEDOT/PSS blends and the nanowire has an outer diameter of ca. 100 nm. The results also indicate that the morphology of PEDOT/PSS-ZnO nanocomposite is greatly influenced by external vacuum condition and aging time. The feasible and simple approach that we have developed provides a new strategy for the synthesis of novel one-dimensional nanocomposites.