Gui Chen

Hierarchical Three-Dimensional ZnCo2O4 Nanowire Arrays/Carbon Cloth Anodes for a Novel Class of High-Performance Flexible Lithium-Ion Batteries

Flexible electronics is an emerging and promising technology for next generation of optoelectronic devices. Herein, hierarchical three-dimensional ZnCo(2)O(4) nanowire arrays/carbon cloth composites were synthesized as high performance binder-free anodes for Li-ion battery with the features of high reversible capacity of 1300-1400 mAh g(-1) and excellent cycling ability even after 160 cycles with a capacity of 1200 mAh g(-1). Highly flexible full batteries were also fabricated, exhibiting high flexibility, excellent electrical stability, and superior electrochemical performances.

High-detectivity InAs nanowire photodetectors with spectral response from ultraviolet to near-infrared

AbstractInAs is a direct, narrow band gap (0.354 eV) material with ultrahigh electron mobility, and is potentially a good optoelectronic device candidate in the wide UV-visible-near-infrared region. In this work we report the fabrication of InAs nanowire-based photodetectors, which showed a very high photoresponse over a broad spectral range from 300 to 1,100 nm. The responsivity, external quantum efficiency and detectivity of the device were respectively measured to be 4.4 × 103 AW−1, 1.03 × 106%, and 2.6 × 1011 Jones to visible incident light. Time dependent measurements at different wavelengths and under different light intensities also demonstrated the fast, reversible, and stable photoresponse of our device. Theoretical calculations of the optical absorption and the electric field component distribution were also performed to elucidate the mechanism of the enhanced photoresponse. Our results demonstrate that the single-crystalline InAs NWs are very promising candidates for the design of high sensitivity and high stability nanoscale photodetectors with a broad band photoresponse.

High-Performance Hybrid Phenyl-C61-Butyric Acid Methyl Ester/Cd3P2 Nanowire Ultraviolet-Visible-Near Infrared Photodetectors

In this work, single-crystalline p-type Cd3P2 nanowires (NWs) were synthesized on a Cd sheet via a facile chemical vapor deposition method. Then field-effect transistors and high-performance photodetectors were fabricated based on these NWs. It was found that hole mobility of a pristine Cd3P2 NW is around 2.94 cm(2) V(-1) s(-1). Meanwhile, high responsivity and photoconductive gain were observed on these devices across a broad spectral range covering UV-visible to NIR with high stability and reproducibility. Furthermore, hybrid organic-inorganic n-type phenyl-C61-butyric acid methyl ester (PCBM) and p-type Cd3P2 NW heterojunction photodetectors were also fabricated, exhibiting much improved photocurrent and photoconductive gain, as compared to the device made of pristine Cd3P2 NWs. Intriguingly, the flexible hybrid photodetectors have been fabricated on plastic substrates and characterized under various bending conditions, demonstrating their excellent flexibility and robustness. The high performance and flexibility of the hybrid photodetectors are promising for further applications requiring large-area, high-sensitivity, and high-speed photodetectors with broad-spectrum photoresponse.

Tin sulfide nanoribbons as high performance photoelectrochemical cells, flexible photodetectors and visible-light-driven photocatalysts

Tin sulfide (SnS) nanoribbons with the thickness of ca. 10–20 nm and length up to several microns were synthesized via a facile polyol refluxing process. The photoconductive properties of the SnS nanoribbons were tested by assembling the samples into photoelectrochemical (PEC) cells, exhibiting excellent photosensitivity with the features of rapid response and recover time, and stable on/off cycle performance to the stimulated sunlight. The photocurrent density can reach to around 87 μA cm−2, which is the highest one among all reported SnS photoelectrodes. Flexible photodetectors were then fabricated on PET substrates, showing fast response to visible light with different intensities. Photocatalytic properties of the as-synthesized SnS nanoribbons were also studied by photocatalytic degradation of methylene blue (MB). Almost all of MB was decomposed within 2 h, indicating the SnS nanoribbons are good candidates for high performance photocatalysts.

Fast fabrication of a WO3·2H2O thin film with improved electrochromic properties

By using electrochemical activated FTO glass as both a substrate and catalyst, we developed a facile and fast method to fabricate a WO3·2H2O thin film with a thickness of ∼100 nm. Due to the specific layered crystal structure of the dihydrated phase and the good contact with the transparent conductive oxides (TCOs) layer, the as-prepared WO3·2H2O thin film achieved a fast coloration/bleaching response speed (tc,90% = 3.2 s, tb,90% = 1.2 s), excellent cyclic stability, wide optical modulation range up to 53.8% and a high coloration efficiency of 107.8 cm2 C−1. A solid-state electrochromic device with a size of 5 cm × 5 cm was also fabricated, exhibiting high transparency contrast and good reversibility between the bleached and colored states.

Fabrication of high-quality ZnTe nanowires toward high-performance rigid/flexible visible-light photodetectors

ZnTe is an important p-type semiconductor with great applications as field-effect transistors and photodetectors. In this paper, individual ZnTe nanowires based field-effect transistors was fabricated, showing evident p-type conductivity with an effect mobility of 11.3 cm(2)/Vs. Single ZnTe nanowire based photodetectors on rigid silicon substrate exhibited high sensitivity and excellent stability to visible incident light with responstivity and quantum efficiency as high as 1.87 × 10(5) A/W and 4.36 × 10(7)% respectively and are stable in a wide temperature range (25-250 °C). The polarization-sensitivity of the ZnTe nanowires was studied for the first time. The results revealed a periodic oscillation with the continuous variation of polarization angles. Besides, flexible photodetectors were also fabricated with the features of excellent flexibility, stability and sensitivity to visible incident light. Our work would enable application opportunities in using ZnTe nanowires for ultrahigh-performance photodetectors in scientific, commercial and industrial applications.

High performance rigid and flexible visible-light photodetectors based on aligned X(In, Ga)P nanowire arrays

InP and GaP nanowires (NWs) were synthesized via a simple thermal evaporation method for applications as high performance visible-light photodetectors. Individual InP NW field-effect transistors (FETs) were fabricated to study their electronic transport and photoresponse characteristics, which exhibited typical n-type transistor characteristics with an efficient electron mobility of 1.21 cm2 V−1 s−1, a fast response time (∼0.1 s) and good sensitivity with a spectral responsivity of 779.14 A W−1 and a high quantum efficiency of 1.53 × 105% to visible light irradiation. Using the contact printing process, large scale aligned InP NW arrays were assembled on both rigid SiO2/Si and flexible PET substrates. Both rigid and flexible InP NW array based photodetectors demonstrated excellent photoresponse performance, especially a faster response, for example, from 0.1 s to 80 ms. In addition, the flexible InP NW array based photodetectors exhibited good flexibility, good folding endurance and electrical stability. Using similar processes, aligned GaP NW array based photodetectors were also fabricated on SiO2/Si and PET substrates, which also exhibited fast, reversible, and stable photoresponse properties. These merits demonstrate that the as-prepared InP and GaP NWs are good candidates with substantial potential for future electronic and optoelectronic nanodevice applications.

Selective synthesis of Sb2S3 nanoneedles and nanoflowers for high performance rigid and flexible photodetectors.

Needle-like and flower-like antimony sulfide nanostructures were synthesized and applied for both rigid and flexible photodetectors. Rigid photodetectors based on both nanostructures have the features of linear photocurrent characteristics, low linear dynamic range and good sensitivity to light intensity. Especially, the rigid Sb2S3 nanoflowers photodetector has high photoresponse characteristics and its response time and decay time were found to be relatively fast as 6 ms and 10 ms respectively. The flexible Sb2S3 nanoflowers photodetector has high flexible, light-weight and adequate bendability with a response time of about 0.09 s and recovery time of 0.27 s. Our results revealed that the rigid and flexible photodetectors based on Sb2S3 nanostructures have great potential in next generation optoelectronic devices.

Contact printing of horizontally aligned Zn2GeO4 and In2Ge2O7 nanowire arrays for multi-channel field-effect transistors and their photoresponse performances

The ternary oxides, Zn2GeO4 and In2Ge2O7 nanowires, are promising n-type semiconductors with outstanding transport properties for high performance electronic devices. By using the direct contact printing process, we reported the assembly of horizontally aligned Zn2GeO4 and In2Ge2O7 nanowire arrays to be used as building blocks for high performance multi-channel field-effect transistors. The as-fabricated multi-channel transistors exhibited higher voltage stability and repeatability than their single nanowire based counterparts. The effective mobilities of the multi-channel field-effect transistors were calculated to be 25.44 cm2 V−1 s−1 and 11.9 cm2 V−1 s−1, comparable to the single-channel FETs. The as-fabricated multi-channel transistors were also used as high performance photodetectors, exhibited a high sensitivity to ultraviolet light illumination with a photoconductive gain and quantum efficiency as high as 1.034 × 105 and 1.032 × 107% for Zn2GeO4 nanowires and 2.58 × 105 and 2.617 × 107% for In2Ge2O7 nanowires.

Carbonized poly(vinylidene fluoride)/graphene oxide with three-dimensional multiscale-pore architecture as an advanced electrode material

A low-cost, mass-produced, dry-gel-based method for fabricating graphene based electroactive materials relevant to energy storage has been reported. This technique combines thermal decomposition of carbon-based materials for the formation of ultramicropores/micropores and freeze drying of graphene gels for the formation of mesopores/macropores. The as-fabricated pore-rich carbon materials show electrochemical performances with superior characteristics of stabilization, specific capacitance and rate capability, demonstrating their great potential applications in clean energy.