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1.
Artigo em Inglês | MEDLINE | ID: mdl-38669621

RESUMO

HgTe colloidal quantum dots (CQDs) are one of few materials that can realize near-to-midwave infrared photodetection. And the quality of HgTe CQD directly affects the performance of photodetection. In this work, we optimize the method of synthesizing HgTe CQDs to reduce the defect concentration, therefore improving the photoelectric properties. The photodetector based on HeTe CQD can respond to the light from the visible to mid-infrared band. Notably, a photoresponse to 4000 nm light at room temperature is realized. The responsivity and detectivity are 90.6 mA W-1 and 6.9 × 107 Jones under 1550 nm light illumination, which are better than these of most reported HgTe CQD photodetectors. The response speed reaches a magnitude of microseconds with a rising time of τr = 1.9 µs and a falling time of τf = 1.5 µs at 10 kHz under 1550 nm light illumination.

2.
Chemphyschem ; 25(5): e202300960, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38179835

RESUMO

Prussian blue analogues (PBAs) have advantages such as high voltage and low cost, making them one kind of the promising positive electrode materials for sodium-ion batteries. Particle dispersion is a key physical parameter of electrode materials, and understanding its impact on electrochemical performance is a prerequisite for obtaining high-performance PBAs. In this article, two PBAs samples with different particle dispersion were synthesized through sodium citrate-assisted co-precipitation method by means of staying and stirring. The influence of particle dispersion on electrochemical performance was investigated through polarization curve and AC impedance tests. It was found that PBAs with well-dispersed particles exhibited excellent rate performance, with a capacity of ~120 mAh g-1 at 1 C rate and a capacity retention of 75 % after 100 cycles. The capacity retention rate could reach 63 % at 5 C rate, far higher than that of PBAs samples with poor particle dispersion. From the perspective of electrochemical kinetics analysis, it has been shown that PBAs with well-dispersed particles exhibit smaller electrochemical polarization and faster Na+ diffusion reaction kinetics, which are key factors in achieving excellent rate performance.

3.
Inorg Chem ; 62(33): 13632-13638, 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37552842

RESUMO

Understanding the growth mechanisms of HgTe nanoparticles (NPs) with varied shapes is crucial for their applications in infrared photodetection. Here, we investigated the growth mechanisms of HgTe NPs with nanorod, sphere, and tetrahedral shapes in depth. The HgTe NPs with a nanorod shape are obtained at low reaction temperatures and formed by breaking tetrapod branches, while HgTe NPs with sphere and tetrahedron shapes have been further achieved at increased reaction temperatures. The systematic crystal analyses demonstrate this effective shape control is related to the synergic effect among the anisotropic passivation of oleylamine, surface free energy, and reaction temperatures. Our findings have deepened the understanding of shape control of the HgTe NPs and inspired a growing passion in the design and engineering of infrared photodetectors using HgTe NPs.

4.
Nanoscale ; 14(36): 13187-13191, 2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36047440

RESUMO

Two-dimensional (2D) elementary tellurium (Te) has attracted intensive attention due to its potential applications in short-wave infrared photodetector devices. Here, we report hydrothermally synthesized 2D Te nanoflakes for short-wave infrared photodetectors with high performance. A Te-based photodetector exhibits a peak responsivity of 51.85 A W-1 at a 1550 nm wavelength, attributed to the efficient absorption of the phonons of 2D Te nanoflakes. Besides, the rising and decay time of the Te photodetector is calculated to be ∼19 µs and ∼21 µs, respectively, due to the rapid diffusion of charge carriers. In addition, Te-photodetectors exhibit a high specific detectivity (D*) of 1.88 × 1010 Jones and a superior external quantum efficiency (EQE) of 4148%. Our findings have demonstrated the development of high-performance short-wave infrared photodetectors with fast responses based on 2D Te nanoflakes.

5.
Nanoscale Res Lett ; 16(1): 58, 2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33830397

RESUMO

In this study, polyaniline (PANI) is prepared by means of chemical oxidization polymerization and directly loaded on the modified fiber ball (m-FB) to obtain macroscale polyaniline/modified fiber ball (PANI/m-FB) composite, and then its removal ability of Cr(VI) is investigated. The effects of different parameters such as contact time, pH value and initial concentration on Cr(VI) removal efficiency are discussed. The experimental results illustrate that the favorable pH value is 5.0 and the maximum removal capacity is measured to be 293.13 mg g-1. Besides, PANI/m-FB composites can be regenerated and reused after being treated with strong acid. The kinetic study indicates that the adsorption procedure is mainly controlled by chemical adsorption. More importantly, the macroscale of composites can avoid secondary pollution efficiently. Benefiting from the low cost, easy preparation in large scale, environmentally friendly, excellent recycling performance as well as high removal ability, PANI/m-FB composites exhibit a potential possibility to remove Cr(VI) from industrial waste water. The polyaniline (PANI) was coated on modified fiber ball (m-FB) to remove Cr(VI) in waste water, and this kind of PANI/m-FB composites can avoid secondary pollution efficiently due to its macrostructure. Furthermore, the removal capacity can reach to 291.13 mg/g and can be multiple reused.

6.
Nanotechnology ; 31(14): 145203, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-31860897

RESUMO

In this paper, we fabricate ordered pore array (OPA) Ag film coated glass with the aid of polystyrene sphere (PS) array templates. This kind of OPA Ag coated glass has optical advantages of visible transparency, blue and near-infrared resistance. The average visible transmittance is 68%, including a transmission peak of 78% located at 570 nm, and low average transmittance of 48% in the blue light region that is not damaging to the eyes. The near-infrared light blocking rate is 67%, among which 40% light is reflected directly, indicating the reflection domination.

7.
Nanoscale Res Lett ; 14(1): 298, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31463645

RESUMO

Eu2+-activated phosphors are widely applied in lighting and display areas because of their good optical performance. In this paper, an excellent green-emitting zeolite-3A: 1.3 wt% Eu phosphor is prepared by a green and eco-friendly high-thermal reaction method without any reducing atmosphere or agents. Meanwhile, the reducing mechanism from Eu3+ ions to Eu2+ ions is investigated. The experiment results show that the morphology, crystal structure, and luminescent property are affected by sintering temperature. The resulting sample shows the broad excitation band is in the range of 310-450 nm and the peak of the broad emission band is located at 523 nm. Furthermore, zeolite-3A: 1.3 wt% Eu phosphor is encapsulated on a commercial UV-emitting chip to fabricate a purity green light-emitting diode (LED) with the Commission Internationale de L'Eclairage (CIE) color coordinates at (0.295, 0.537).

8.
Nanoscale Res Lett ; 13(1): 401, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30536050

RESUMO

The hollow polyaniline (PANI) micro/nanospheres are obtained through a simple monomer polymerization in alkaline solution with Triton X-100 Micelles as soft templates. The hollow PANI micro/nanospheres demonstrate rapid and effective removal ability for Chromium (VI) (Cr (VI)) in a wide pH range, and the maximum removal capacity can reach 127.88 mg/g at pH 3. After treated with acid, the used hollow PANI micro/nanospheres have about the similar removal capacity of Cr (VI) from wastewater.

9.
Sci Rep ; 7(1): 144, 2017 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-28273944

RESUMO

Composite hollow nanostructure composed by transition metal oxides are promising materials in electrochemistry, catalyst chemistry and material science. In this contribution, necklace-like NiO-CuO heterogeneous composite hollow nanostructures were synthesized by annealing Ni/Cu superlattice nanowires in air. Two kinds of morphologies including CuO nanotube linked core-shell structures and CuO nanotube linked hollow structures were obtained. The structure can be tuned easily by adjusting the relative length of Cu segments in Ni/Cu superlattice nanowires and the annealing temperature. The relative diffusion amount of Cu to Ni segments was proved to be the key factor to influence the annealed sample morphology. The formation mechanism was discussed in detail based on Kirkendal effect and high temperature oxidation of alloy. We demonstrated that hollow structure or core-shell structure is related to whether the oxidation exists only in external sites or co-exists in external and internal sites during annealing.

10.
Phys Chem Chem Phys ; 18(48): 32691-32696, 2016 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-27711600

RESUMO

Tellurium nanowires (NWs) are attractive one-dimensional materials for many applications, yet most synthesis processes require hazardous chemical reducing agents and extreme operating conditions. Here we described a solvothermal synthesis of Te NWs using a non-toxic reducing agent, ascorbic acid. Then the Te NWs were assembled into a well-aligned film through a stirring-assisted oil-water-air interface assembly method and a Te NWs photodetector was fabricated which is sensitive to infrared radiation. The photodetector based on the well-aligned Te NWs film had a series of more excellent photoelectric properties than that based on those being randomly oriented. For example, the photoresponsivity of the former is 103 times larger, and the response time is 1.15 × 103 times shorter, than those of the latter.

11.
Nanotechnology ; 27(37): 375601, 2016 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-27487089

RESUMO

One-dimensional noble-metal Ag nanoparticle chains have been prepared by electrodepositing Ag/Bi superlattice nanowires in a porous anodic alumina oxide (AAO) template and following an annealing process in vacuum. It is found that Bi, as a sacrificial metal, can be removed completely after annealing at 450 °C with a vacuum degree of 10(-5) Torr. The regulation of particle size, shape and interparticle spacing of Ag NP chains has been realized by adjusting the segment length of the Ag/Bi superlattice nanowires and the annealing condition. With an extension of the annealing time, it is observed that Ag particles display the transform trend from ellipsoid to sphere. Our findings could inspire further investigation on the design and fabrication of metal nanoparticle chains.

12.
Chem Commun (Camb) ; 50(92): 14317-20, 2014 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-24955939

RESUMO

This communication reports an approach to fabricate large-scale ultrathin open-ended porous TiO2 membranes (UOP-TMs) with ordered straight-through pores. Bi nanodot arrays on Si substrates are obtained by using the UOP-TMs as surface patterning masks.

13.
Sci Rep ; 4: 3601, 2014 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-24398625

RESUMO

Anodic aluminum oxide based photonic crystals with periodic porous structure have been prepared using voltage compensation method. The as-prepared sample showed an ultra-narrow photonic bandgap. Asymmetric line-shape profiles of the photonic bandgaps have been observed, which is attributed to Fano resonance between the photonic bandgap state of photonic crystal and continuum scattering state of porous structure. And the exhibited Fano resonance shows more clearly when the sample is saturated ethanol gas than air-filled. Further theoretical analysis by transfer matrix method verified these results. These findings provide a better understanding on the nature of photonic bandgaps of photonic crystals made up of porous materials, in which the porous structures not only exist as layers of effective-refractive-index material providing Bragg scattering, but also provide a continuum light scattering state to interact with Bragg scattering state to show an asymmetric line-shape profile.

14.
Nanotechnology ; 22(26): 265602, 2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-21576782

RESUMO

A facile and universal synthetic approach for preparing superlattice nanowire (SLNW) arrays is developed. In this method, two kinds of elements are alternately electrodeposited into the holes of the anodic alumina oxide (AAO) template, automatically in separate electrolytes by a programmed device. This method is not restricted by the relative values of the reduction potentials of the elements, and the deposition of each element can be controlled independently. Three kinds of representative SLNW arrays containing noble-metal material (Ag/Ni), thermoelectric material (Bi/Sb) and magnetic material (Ni/Cu) with adjustable segment length are fabricated successfully.

15.
J Nanosci Nanotechnol ; 10(8): 5471-4, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21125921

RESUMO

Large-scale SnO2 mesoporous nanowires have been successfully synthesized by an improved sol-gel method within the nanochannels of porous anodic alumina templates. In this method, chloride of stannic and urea are used as precursors, chloride of stannic is acting as source of tin ions, and urea offers a basic medium through its hydrolysis. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and selected-area electron diffraction are used to characterize the SnO2 mesoporous nanowires. It is found that the as-prepared nanowires consist of SnO2 nanoparticles and pores. They can be indexed as rutile structures and diameters are about 50-70 nm. The growth mechanism of the mesoporous nanowires is also been discussed. The band gap of the as-prepared mesoporous nanowires is 3.735 eV, determined by UV/visible absorption spectral results. The SnO2 mesoporous nanowires show strong and stable photoluminescence with emission peak centered at 3.730 eV, which has never been reported in nanowires. It could be attributed to the exciton recombination.

16.
Nanoscale Res Lett ; 5(11): 1800-1803, 2010 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-21124630

RESUMO

In this article, the porous-ZnO-nanobelt film was synthesized by oxidizing the ZnSe-nanobelt film in air. The experiment results show that the porous-ZnO-nanobelt film possesses enhanced photocatalytic activity compared with the ZnO-nanobelt film, and can be used as recyclable photocatalysts. The enhanced photocatalytic activity of the porous-ZnO-nanobelt film is attributed to the increased surface area. Therefore, turning the 1D-nanostructure film into porous one may be a feasible approach to meet the demand of photocatalyst application.

17.
Nanoscale Res Lett ; 5(9): 1387-1392, 2010 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-20802787

RESUMO

In this paper, ZnGa(2)O(4) hierarchical nanostructures with comb-like morphology are fabricated by a simple two-step chemical vapor deposition (CVD) method: first, the Ga(2)O(3) nanowires were synthesized and employed as templates for the growth of ZnGa(2)O(4) nanocombs; then, the as-prepared Ga(2)O(3) nanowires were reacted with ZnO vapor to form ZnGa(2)O(4) nanocombs. Before the reaction, the Au nanoparticles were deposited on the surfaces of Ga(2)O(3) nanowires and used as catalysts to control the teeth growth of ZnGa(2)O(4) nanocombs. The as-prepared ZnGa(2)O(4) nanocombs were highly crystallized with cubic spinel structure. From the photoluminescence (PL) spectrum, a broad band emission in the visible light region was observed of as-prepared ZnGa(2)O(4) nanocombs, which make it promising application as an optical material.

18.
Opt Lett ; 35(5): 727-9, 2010 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-20195333

RESUMO

The transmission phase grating on anodic alumina membrane (AAM) was fabricated by a lithography and chemical etching method to demonstrate the feasibility of fabricating diffractive optical elements on AAM matrix. The monochromatic light diffraction property of the sample grating was tested using lasers with wavelengths of 532 and 650 nm, respectively. The measured diffraction efficiencies of zeroth and first orders were in good agreement with the calculated results. This method may offer an approach to prepare surface pattern on alumina and could be used in fabricating diffractive optical components such as linear gratings.

19.
J Phys Condens Matter ; 21(24): 245403, 2009 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-21693945

RESUMO

Submicrometer-sized Ga particles were dispersed in polymethylmethacrylate (PMMA) matrix by an ultrasonic vibration and sedimentation method. The solid phase transition from γ-Ga to δ-Ga and its Ga particle size dependence were studied by means of differential scanning calorimeter measurements. It was shown that a solid-solid phase transition corresponding to the [Formula: see text]-Ga one happened in Ga particles upon cooling. Moreover, the ratio of the particles undergoing the solid phase transition to all particles increases with decrease of the particle size.

20.
Nanoscale Res Lett ; 4(7): 665-7, 2009 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-20596519

RESUMO

We have successfully prepared anodized alumina membrane distributed Bragg reflector (DBR) using electrochemical anodization method. The transmission peak of this distributed Bragg reflector could be easily and effectively modulated to cover almost any wavelength range of the whole visible spectrum by adjusting anodization temperature.

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