检索结果-南通市图书馆

In situ growth of different numbers of gold nanoparticles on MoS_2 with enhanced electrocatalytic activity for hydrogen evolution reaction

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第6期27卷 473-478页

作者：赵宣何大伟王永生付晨 Key Laboratory of Luminescence and Optical Information Beijing Jiaotong University

Producing hydrogen through a hydrogen evolution reaction（HER） by splitting water at the suitable overpotential is a great alternative to solving the problems of environmental pollution and the energy crisis. Molybdenum sulfide（MoS2）has attracted extensive attention as one of the most promising catalytic materials for HER. In this work, we design a facile method to in situ grow gold nanoparticles（Au NPs） on MoS2. Different numbers of Au NPs with MoS2 are used to find the best catalytic activity. Due to the larger active surface area and higher conductivity of the Au–MoS2 composites, all the Au–MoS2 composites exhibit more enhanced HER electroactivity than pure MoS2. In brief, the new material architecture exhibits optimized HER activity with a low onset overpotential of 0.12 V, low Tafel slope of 0.163 V·dec^（-1）, and an excellent stability in acidic solution.

关键词： MoS2 AuNPs hydrogen evolution reaction electrocatalysts

Facile and controllable synthesis of molybdenum disulfide quantum dots for highly sensitive and selective sensing of copper ions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第5期27卷 419-423页

作者：李雪何大伟王永生胡音赵宣付晨吴静燕 Key Laboratory of Luminescence and Optical Information Beijing Jiaotong University

Molybdenum disulfide quantum dots（MoS2QDs） were synthesized via a hydrothermal method using sodium molybdate and cysteine as molybdenum and sulfur sources, respectively. The optimal hydrothermal time was studied. Furthermore, the as synthesized water-soluble MoS2QDs were used as a fluorescence probe for the sensitive and selective detection of copper ions. The fluorescence of the MoS2QDs was quenched after the addition of copper ions; the reason may be that the transfer of the excited electron from QDs to copper ions leads to the reduction of the radiative recombination.The fluorescence quenching of MoS2QDs is linearly dependent on the copper ions concentration ranging from 0.1 μM to600 μM, the limit of detection is 0.098 μM, which is much lower than that of existing methods. Moreover, the MoS2QDs show highly selectivity towards the detection of copper ions.

关键词： MoS2 quantum dots photoluminescence fluorescent probe

Label-free tungsten disulfide quantum dots as a fluorescent sensing platform for highly efficient detection of copper(Ⅱ) ions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第6期26卷 275-279页

作者：赵宣何大伟王永生胡音付晨李雪 Key Laboratory of Luminescence and Optical Information Beifing Jiaotong University Beijing 100044 China

A fluorescent probe for the sensitive and selective determination of copper ion（Cu^2＋） is presented. It is based on the use of tungsten disulfide quantum dots（WS2 QDs） which is independent of the p H of solution and emits strong blue fluorescence. Copper ions could cause aggregation of the WS2 QDs and lead to fluorescence quenching of WS2 QDs. The change of fluorescence intensity is proportional to the concentration of Cu^2＋, and the limit of detection is 0.4 μM. The fluorescent probe is highly selective for Cu^2＋ over some potentially interfering ions. These results indicate that WS2 QDs,as a fluorescent sensing platform, can meet the selective requirements for biomedical and environmental application.

关键词： WS2 quantum dots photolulninescence biosensor

Phase-locked all-optical differential polarization demodulation

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第6期23卷 283-286页

作者：史骥李政勇张革王海洋王一旭吴重庆 Key Laboratory of Luminescence and Optical Information of Ministry of Education Beijing Jiaotong University

A novel scheme of differential polarization demodulation is presented and demonstrated based on a polarized asym- metrical Mach-Zehnder interferometer configuration with polarization control. To enhance the stability of the demodulator, a phase-lock device is designed, and it is composed of a symmetric 3 × 3 coupler and a feedback circuit. For further estab- lishing a differential polarization-shift keying （DPolSK） transmission system, we successfully carry out the demodulation experiments on 10-Gb/s DPolSK optical signals for the first time. Due to the all-optical structure with phase-lock, our scheme is available to realize the DPolSK optical communication in practical optical fiber systems.

关键词： optical communication systems demodulation polarization

Highly sensitive polymer photodetectors with a wide spectral response range

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第1期26卷 530-536页

作者：高米勒王文斌李凌亮苗建利张福俊 Key Laboratory of Luminescence and Optical Information of Ministry of Education Beijing Jiaotong University Beijing 100044 China

A series of highly sensitive polymer photodetectors（PPDs） was fabricated with P3HT100-x：PBDT-TS1x：PC71BM1 as the active layers, where x represents the PBDT-TS1 doping weight ratio in donors. The response range of PPDs can cover from the UV to near-infrared regions by adjusting the PBDT-TS1 doping weight ratio. The best external quantum efficiency（EQE） values of ternary PPDs with P3HT：PBDT-TS1：PC（71）BM（50：50：1 wt/wt/wt） as the active layers reach 830%, 720%,and 330% under 390-, 625-, and 760-nm light illumination and-10 V bias, respectively. The large EQE values indicate that the photodetectors utilise photomultiplication（PM）. The working mechanism of PM-type PPDs can be attributed to interfacial trap-assisted hole tunnelling injection from the external circuit under light illumination. The calculated optical field and photogenerated electron volume density in the active layers can well explain the EQE spectral shape as a function of the PBDT-TS1 doping weight ratio in donors.

关键词： conducting polymers photodetectors photomultiplication

Improved performance of P3HT:PCBM solar cells by both anode modification and short-wavelength energy utilization using Tb(aca)_3phen

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第9期23卷 585-589页

作者：卓祖亮王永生何大伟富鸣 Key Laboratory of Luminescence and Optical Information of the Ministry of Education Beijing Jiaotong University

The performance of P3HT：PCBM solar cells was improved by anode modification using spin-coated Tb（aca）3phen ultrathin films. The modification of the Tb（aca）3phen ultrathin film between the indium tin oxide （ITO） anode and the PEDOT：PSS layer resulted in a maximum power conversion efficiency （PCE） of 2.99% compared to 2.66% for the reference device, which was due to the increase in the short-circuit current density （Jsc）. The PCE improvement could be attributed to the short-wavelength energy utilization and the optimized morphology of the active layers. Tb（aca）3phen with its strong down-conversion luminescence properties is suitable for the P3HT：PCBM blend active layer, and the absorption region of the ternary blend films is extended into the near ultraviolet region. Furthermore, the crystallization and the surface morphol- ogy of P3HT：PCBM films were improved with the Tb（aca）3phen ultrathin film. The ultraviolent-visible absorption spectra, atomic force microscope （AFM）, and X-ray diffraction （XRD） of the films were investigated. Both anode modification and short-wavelength energy utilization using Tb（aca）3phen in P3HT：PCBM solar cells led to about a 12% PCE increase.

关键词： P3HT：PCBM anode modification polymer solar cells

Facilitative effect of graphene quantum dots in MoS_2 growth process by chemical vapor deposition

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第1期27卷 579-582页

作者：张璐王永生董艳芳赵宣付晨何大伟 Key Laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic TechnologyBeijing Jiaotong University

The substrate treatment with seeding promoter can promote the two-dimensional material lateral growth in chemical vapor deposition （CVD） process. Herein, graphene quantum dots （GQDs） as a novel seeding promoter were used to obtain uniform large-area MoS2 monolayer. The obtained monolayer MoS2 films were confirmed by optical microscope, scanning electron microscope, Raman and photoluminescence spectra. Raman mapping revealed that the MoS2 monolayer was largely homogeneous.

关键词： MoS2 seed graphene quantum dots （GQDs） continuous film

Solvent additive-free ternary polymer solar cells with 16.27% efficiency

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2019年第8期64卷 504-506页

作者： Qiaoshi An Xiaoling Ma Jinhua Gao Fujun Zhang School of Electrical Engineering Beijing Jiaotong University Key Laboratory of Luminescence and Optical Information Ministry of EducationBeijing Jiaotong University

Ternary strategy has been commonly demonstrated as an efficient method to improve the performance of polymer solar cells(PSCs), which has great potential in application of PSCs due to the simple device fabrication.

关键词： Solvent additive-free ternary polymer solar cells with 16.27 efficiency

Enhanced microwave absorption performance of MOF-derived hollow Zn-Co/C anchored on reduced graphene oxide

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第6期30卷 610-616页

作者：王玥何大伟王永生 Key Laboratory of Luminescence and Optical Information Ministry of EducationInstitute of Optoelectronic TechnologyBeijing Jiaotong UniversityBeijing 100044China

Composite materials assembled by metal/carbon nanoparticles and 2 D layered flakes can provide abundant interfaces,which are beneficial for high-performance microwave absorbers. Herein, Zn-Co/C/RGO composites, composed of ZnCo metal-organic framework-derived Zn-Co/C nanoparticles and reduced graphene oxide(RGO), were obtained through a facile method. The multilayer structure was due to the introduction of hollow Zn-Co/C nanoparticles in the RGO sheets. ZnCo/C nanoparticles provided abundant polarization and dipole centers on the RGO surface, which enhanced the microwave absorption abilities. Different concentrations of RGO were introduced to optimize impedance matching. The minimum reflection loss(R_(L)) of Zn-Co/C/RGO with a thickness of 1.5 mm reached-32.56 dB with the bandwidth corresponding to R_(L) at-10 dB, which can reach 3.92 GHz, while a minimum R_(L) of-47.15 dB at 11.2 GHz was also obtained at a thickness of 2.0 mm. The electromagnetic data demonstrate that Zn-Co/C/RGO presented excellent absorption performance and has potential for application in the microwave absorption field.

关键词： microwave absorption metal nanoparticles metal-organic framework(MOF) reduced graphene oxide