Pengbo Wan

Transparent Conducting Films of Hierarchically Nanostructured Polyaniline Networks on Flexible Substrates for High‐Performance Gas Sensors

Transparent chemical gas sensors are assembled from a transparent conducting film of hierarchically nanostructured polyaniline (PANI) networks fabricated on a flexible PET substrate, by coating silver nanowires (Ag NWs) followed by the in situ polymerization of aniline near the sacrificial Ag NW template. The sensor exhibits enhanced gas sensing performance at room temperature in both sensitivity and selectivity to NH3 compared to pure PANI film.

Amorphous Co-doped MoS2 nanosheet coated metallic CoS2 nanocubes as an excellent electrocatalyst for hydrogen evolution

An amorphous Co-doped MoS2 coated highly crystalline pyrite-phase CoS2 hierarchical nanoarray exhibits ultrahigh activity towards acidic hydrogen evolution with a low onset potential (∼44 mV) and a small overpotential of ∼110.5 mV for driving the current density of ∼10 mA cm−2, ascribed to its novel hierarchical structure and the Co doping caused synergistic effects.

A metallic CoS2 nanopyramid array grown on 3D carbon fiber paper as an excellent electrocatalyst for hydrogen evolution

A CoS2 nanopyramid array with a low mass loading (∼0.625 mg cm−2) fabricated on 3D carbon fiber paper exhibits ultrahigh activity towards acidic hydrogen evolution with a low onset potential (∼61 mV) and a small overpotential (∼140 mV) for driving a current density of ∼100 mA cm−2, ascribed to the one-step solvothermal synthesis, unique 3D nanostructure and intrinsic metallic properties of the electrocatalyst.

Fabrication of reactivated biointerface for dual-controlled reversible immobilization of cytochrome C.

A light or pH dual-responsive reactivated biointerface is fabricated using of photocontrolled reversible inclusion and exclusion reactions between photoresponsive azobenzene-containing self-assembled monolayer and pH-responsive poly(acrylic acid) polymer grafted with cyclodextrins. The dual-controlled reactivated biointerface can be employed for reversible immobilization of redox protein-Cytochrome c, triggered by dual external stimuli-light and pH.

Flexible Transparent Electronic Gas Sensors.

Flexible and transparent electronic gas sensors capable of real-time, sensitive, and selective analysis at room-temperature, have gained immense popularity in recent years for their potential to be integrated into various smart wearable electronics and display devices. Here, recent advances in flexible transparent sensors constructed from semiconducting oxides, carbon materials, conducting polymers, and their nanocomposites are presented. The sensing material selection, sensor device construction, and sensing mechanism of flexible transparent sensors are discussed in detail. The critical challenges and future development associated with flexible and transparent electronic gas sensors are presented. Smart wearable gas sensors are believed to have great potential in environmental monitoring and noninvasive health monitoring based on disease biomarkers in exhaled gas.

Flexible Transparent Films Based on Nanocomposite Networks of Polyaniline and Carbon Nanotubes for High‐Performance Gas Sensing

A flexible, transparent, chemical gas sensor is assembled from a transparent conducting film of carbon nanotube (CNT) networks that are coated with hierarchically nanostructured polyaniline (PANI) nanorods. The nanocomposite film is synthesized by in-situ, chemical oxidative polymerization of aniline in a functional multiwalled CNT (FMWCNT) suspension and is simultaneously deposited onto a flexible polyethylene terephthalate (PET) substrate. An as-prepared flexible transparent chemical gas sensor exhibits excellent transparency of 85.0% at 550 nm using the PANI/FMWCNT nanocomposite film prepared over a reaction time of 8 h. The sensor also shows good flexibility, without any obvious decrease in performance after 500 bending/extending cycles, demonstrating high-performance, portable gas sensing at room temperature. This superior performance could be attributed to the improved electron transport and collection due to the CNTs, resulting in reliable and efficient sensing, as well as the high surface-to-volume ratio of the hierarchically nanostructured composites. The excellent transparency, improved sensing performance, and superior flexibility of the device, may enable the integration of this simple, low-cost, gas sensor into handheld flexible transparent electronic circuitry and optoelectronic devices.

Healable, Transparent, Room‐Temperature Electronic Sensors Based on Carbon Nanotube Network‐Coated Polyelectrolyte Multilayers

Transparent and conductive film based electronics have attracted substantial research interest in various wearable and integrated display devices in recent years. The breakdown of transparent electronics prompts the development of transparent electronics integrated with healability. A healable transparent chemical gas sensor device is assembled from layer-by-layer-assembled transparent healable polyelectrolyte multilayer films by developing effective methods to cast transparent carbon nanotube (CNT) networks on healable substrates. The healable CNT network-containing film with transparency and superior network structures on self-healing substrate is obtained by the lateral movement of the underlying self-healing layer to bring the separated areas of the CNT layer back into contact. The as-prepared healable transparent film is assembled into healable transparent chemical gas sensor device for flexible, healable gas sensing at room temperature, due to the 1D confined network structure, relatively high carrier mobility, and large surface-to-volume ratio. The healable transparent chemical gas sensor demonstrates excellent sensing performance, robust healability, reliable flexibility, and good transparency, providing promising opportunities for developing flexible, healable transparent optoelectronic devices with the reduced raw material consumption, decreased maintenance costs, improved lifetime, and robust functional reliability.

High‐Performance Water Electrolysis System with Double Nanostructured Superaerophobic Electrodes

Catalysts screening and structural optimization are both essential for pursuing a high-efficient water electrolysis system (WES) with reduced energy supply. This study demonstrates an advanced WES with double superaerophobic electrodes, which are achieved by constructing a nanostructured NiMo alloy and NiFe layered double hydroxide (NiFe-LDH) films for hydrogen evolution and oxygen evolution reactions, respectively. The superaerophobic property gives rise to significantly reduced adhesion forces to gas bubbles and thereby accelerates the hydrogen and oxygen bubble releasing behaviors. Benefited from these metrics and the high intrinsic activities of catalysts, this WES affords an early onset potential (≈1.5 V) for water splitting and ultrafast catalytic current density increase (≈0.83 mA mV(-1) ), resulting in ≈2.69 times higher performance compared to the commercial Pt/C and IrO2 /C catalysts based counterpart under 1.9 V. Moreover, enhanced performance at high temperature as well as prominent stability further demonstrate the practical application of this WES.

Facile Reversible UV-Controlled and Fast Transition from Emulsion to Gel by Using a Photoresponsive Polymer with a Malachite Green Group

In this paper we describe the facile reversible UV-controlled and fast transition from emulsion to gel by using a photoresponsive polymer with a malachite green group. The photoresponsive polymer with the hydrophobic malachite green group can be used for the formation of an oil-in-water emulsion. However, upon UV irradiation of 5 min, the photochromic malachite green group could be ionized to its corresponding cation, leading to the transformation from emulsion to gel. Upon shaking, such gel can recover the emulsion state, and further UV irradiation can turn the emulsion into gel again. Such transition from emulsion to gel by photochemical reaction and reverse shaking treatment can be repeated several times. It is anticipated greatly that this line of research may provide new insight into the mechanism behind stimuli-responsive systems, facilitating the design and synthesis of new responsive molecules for the fabrication of stimuli-responsive materials with designed functions.

Combining host-guest systems with nonfouling material for the fabrication of a biosurface: toward nearly complete and reversible resistance of cytochrome c.

In this letter, a pH-responsive reactivated biointerface is fabricated using an inclusion reaction between an azobenzene-containing self-assembled monolayer and pH-responsive poly(ethylene glycol)-block-poly(acrylic acid) grafted with cyclodextrins. The pH-responsive interface can be switched between an extended state and a relaxed state for the reversible resistance of cytochrome c adsorption completely in cooperation with protein-resistant poly(ethylene glycol).