Co-reporter:Yun-Hang Qiu, Fan Nan, Qiang Wang, Xiao-Dan Liu, Si-Jing Ding, Zhong-Hua Hao, Li Zhou, and Qu-Quan Wang
The Journal of Physical Chemistry C March 30, 2017 Volume 121(Issue 12) pp:6916-6916
Publication Date(Web):March 8, 2017
DOI:10.1021/acs.jpcc.7b00735
Excitation of perovskite CH3NH3PbBr3 crystal generates long-lived carriers, which radiatively recombine via free electrons and holes or localized excitons. Here, we investigate the competitive recombination of free carriers and bound excitons by tuning two-photon excitation wavelength. At excitation far from resonance, the CH3NH3PbBr3 perovskite single crystal shows the free carrier up-conversion emission because the exciton binding energy is comparable with the thermal energy at room temperature. At excitation near resonance (1.97 eV < hνexc < 2.16 eV), the anti-Stokes process with a consistent phonon energy of ∼186 meV is reported for the first time. Furthermore, when the anti-Stokes transition is resonant with localized exciton level below the band, highly efficient up-converted luminescence from the bound exciton recombination is observed. The finding that the excited state recombination kinetics vary versus excitation wavelength, in the present work, is helpful for developing the high-performance optoelectronic devices of lead halide perovskites.
Co-reporter:Da-Jie Yang, Gui-Ming Pan, Si-Jing Ding, Zhong-Hua Hao, Li Zhou, Qu-Quan Wang
Optical Materials 2017 Volume 73(Volume 73) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.optmat.2017.08.035
•Surface plasmon coupling behaviors of metallic nanostructures with a gain material inside are investigated.•A periodic energy exchange phenomenon is observed and is explained as plasmonic Rabi oscillation.•Energy exchange between the two rods happens through the near field coupling.•The gain material enables observation of Rabi oscillations through an increase in the plasmonic lifetime.Strong coupling in nanostructures can bring intriguing optical phenomena such as ultrafast Rabi oscillation—periodical energy exchange phenomenon between two modes. Rabi splitting appears in the frequency-domain spectra for strong coupling system. However, in metallic nanosystems the time-domain Rabi oscillations are hard to be observed because the plasmon lifetime is limited by the heavy ohmic losses. Here we report a theoretical investigation of surface plasmon coupling behaviour of two gold nanorods with one being a core-shell rod filled with a gain material and find the periodic energy exchange phenomenon which recalls the concept of Rabi oscillation. The gain material-cored gold-shell structure dipolar mode hybridizes with the solid gold rod quadrupolar mode to form the Fano resonances. Energy exchange between the two rods happens through the near field coupling. Two approaches, to prolong plasmon lifetime by increasing the gain efficiency and to increase Rabi oscillation frequency by increasing the coupling strength, are suggested to increase the Rabi oscillation cycles. Our results offer a way to achieve unique control of light at the nanoscale and further to explore plasmonic Rabi oscillation phenomena in plasmonic nanosystems.Download high-res image (244KB)Download full-size image
Co-reporter:Xiao-Dan Liu, Qiang Wang, Zi-Qiang Cheng, Yun-Hang Qiu, Li Zhou, Qu-Quan Wang
Materials Letters 2017 Volume 206(Volume 206) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.matlet.2017.06.113
•A pure solution-phase synthesis of perovskite nanowires.•Shape is controlled by DMF volume and assisted by long-chain hexadecylammonium.•Tunable absorption and emission in the entire visible region.The solution-phase synthesis of organolead halide perovskite nanowires, nanoplates, and nanoparticles at room temperature is controlled by varying the amount of polar solvent dimethylformamide (DMF) in the presence of long-chain hexadecylammonium (HA). The products exhibit tunable bright emission in the entire visible region (408–733 nm).Download high-res image (90KB)Download full-size image
Co-reporter:Da-Jie Yang;Song-Jin Im;Gui-Ming Pan;Si-Jing Ding;Zhong-Jian Yang;Zhong-Hua Hao;Qu-Quan Wang
Nanoscale (2009-Present) 2017 vol. 9(Issue 18) pp:6068-6075
Publication Date(Web):2017/05/11
DOI:10.1039/C7NR00587C
The “artificial magnetic” resonance in plasmonic metamolecules extends the potential application of magnetic resonance from terahertz to optical frequency bypassing the problem of magnetic response saturation by replacing the conduction current with the ring displacement current. So far, the magnetic Fano resonance-induced nonlinearity enhancement in plasmonic metamolecule rings has not been reported. Here, we use the magnetic Fano resonance to enhance second-harmonic generation (SHG) in plasmonic metamolecule rings. In the spectra of the plasmonic metamolecule, an obvious Fano dip appears in the scattering cross section, while the dip does not appear in the absorption cross section. It indicates that at the Fano dip the radiative losses are suppressed, while the optical absorption efficiency is at a high level. The largely enhanced SHG signal is observed as the excitation wavelength is adjusted at the magnetic Fano dip of the plasmonic metamolecule rings with stable and tunable magnetic responses. We also compare the magnetic Fano dip with the electric case to show its advantages in enhancing the fundamental and second harmonic responses. Our research provides a new thought for enhancing optical nonlinear processes by magnetic modes.
Co-reporter:Kai Chen;Liang Ma;Jia-Hong Wang;Zi-Qiang Cheng;Da-Jie Yang;Ying-Ying Li;Si-Jing Ding;Qu-Quan Wang
RSC Advances (2011-Present) 2017 vol. 7(Issue 42) pp:26097-26103
Publication Date(Web):2017/05/15
DOI:10.1039/C7RA03912C
Semiconductor-based photocatalytic H2 generation is a promising approach to convert solar energy, but single-component photocatalysts still suffer from low efficiency limited by the fast charge recombination. Here, we investigate the high-efficient photocatalytic hydrogen generation of (MoS2–CdS)/Au and (MoS2–CdS)/Pt hybrids, and demonstrate the plasmon-induced electron and energy transfer as well as the co-catalytic effect of metallic nanoparticles (NPs). In these hybrids, visible-light-harvester CdS NPs as well as plasmonic Au NPs or co-catalyst Pt NPs were grown on the monolayer MoS2 nanosheets. The photocatalytic H2 generation under visible light irradiation of (MoS2–CdS)/Au and (MoS2–CdS)/Pt is respectively 3.2 times and 2.4 times that of MoS2–CdS. Intriguingly, the co-effect of Au NPs and Pt NPs leads to the 17 times enhancement. The plasmonic Au NPs in the hybrids play multiply significant roles to increase efficiency of H2 generation: (1) enhance light-harvesting and charge separation in the MoS2–CdS subunit; (2) provide multiply plasmon-mediated hot electron injection channels; (3) amplify the co-catalyst effect of Pt. The present work offers a promising approach for the rational integration of multi-component photocatalyst to improve photocatalytic performance.
Co-reporter:Fan Nan, Si-Jing Ding, Liang Ma, Zi-Qiang Cheng, Yu-Ting Zhong, Ya-Fang Zhang, Yun-Hang Qiu, Xiaoguang Li, Li Zhou and Qu-Quan Wang
Nanoscale 2016 vol. 8(Issue 32) pp:15071-15078
Publication Date(Web):18 Jul 2016
DOI:10.1039/C6NR02633H
Plasmon-mediated energy transfer is highly desirable in photo-electronic nanodevices, but the direct injection efficiency of “hot electrons” in plasmonic photo-detectors and plasmon-sensitized solar cells (plasmon-SSCs) is poor. On another front, Fano resonance induced by strong plasmon–exciton coupling provides an efficient channel of coherent energy transfer from metallic plasmons to molecular excitons, and organic dye molecules have a much better injection efficiency in exciton-SSCs than “hot electrons”. Here, we investigate enhanced light-harvesting of chlorophyll-a molecules strongly coupled to Au nanostructured films via Fano resonance. The enhanced local field and plasmon resonance energy transfer are experimentally revealed by monitoring the ultrafast dynamical processes of the plexcitons and the photocurrent flows of the assembled plexciton-SSCs. By tuning the Fano factor and anti-resonance wavelengths, we find that the local field is largely enhanced and the efficiency of plexciton-SSCs consisting of ultrathin TiO2 films is significantly improved. Most strikingly, the output power of the plexciton-SSCs is much larger than the sum of those of the individual plasmon- and exciton-SSCs. Our observations provide a practical approach to monitor energy and electron transfer in plasmon–exciton hybrids at a strong coupling regime and also offer a new strategy to design photovoltaic nanodevices.
Co-reporter:Ming Chen, Jia-Hong Wang, Zhi-Jun Luo, Zi-Qiang Cheng, Ya-Fang Zhang, Xue-Feng Yu, Li Zhou and Qu-Quan Wang
RSC Advances 2016 vol. 6(Issue 12) pp:9612-9618
Publication Date(Web):15 Jan 2016
DOI:10.1039/C5RA23958C
Metal/rare-earth core/shell hetero-nanostructures combine the optical properties of metal cores and rare-earth shells, which are widely reported and expected to be used in multitask applications. However, there is still no facile and efficient strategy to directly prepare such materials. Herein, we present a facile hydrothermal method for directly coating rare-earth vanadate shells onto the Au nanoparticle (AuNP) cores. Citrate plays a fascinating and critical role in the whole synthesis process, and not only acts as the capping agent to stabilize the as-prepared AuNP cores and the final products but also serves as the complexing agent to assist the nucleation and growth of rare-earth vanadate shells. Interestingly, the grown Au/GdVO4:Eu core/shell NPs have a flower-like shape with tunable plasmon resonance and bright fluorescence. The morphology and crystallinity as well as the growth mechanism and tunable optical properties of the Au/GdVO4:Eu are investigated. The method developed here could be extended for preparing other metal/rare-earth hybrids and the multifunctional products with specific morphology have the potential in the photocatalytic and biomedical application.
Co-reporter:Jia-Hong Wang
The Journal of Physical Chemistry C 2016 Volume 120(Issue 27) pp:14805-14812
Publication Date(Web):June 23, 2016
DOI:10.1021/acs.jpcc.6b03753
Metal/semiconductor heteronanostructures perform wide applications in light-driven physical and chemical processes; in particular, nanomaterials based on anisotropic metal nanocrystals with tunable plasmonic properties have attracted intense interest. We report an efficient hydrothermal method for the synthesis of well-defined ceria (CeO2)-coated gold nanorods (AuNRs) by employing the original hexadecyltrimethylammonium bromide as the ligands and soft-template. Importantly, the Au/CeO2 core/shell NRs have well maintained the tunable longitudinal plasmon resonance of AuNRs in the near-infrared (NIR) region. We demonstrate that this heteronanostructure can accelerate the ceria-dependent Fenton-like reaction through the plasmon-induced hot-electron injection under NIR light illumination. The generation of hot-electrons is further revealed by detecting the NIR-light-driven photocurrent of a photoelectrochemical cell based on the Au/CeO2 core/shell NRs modified electrode.
Co-reporter:Liang Ma, Da-Jie Yang, Zhi-Jun Luo, Kai Chen, Ying Xie, Li Zhou, and Qu-Quan Wang
The Journal of Physical Chemistry C 2016 Volume 120(Issue 47) pp:26996-27002
Publication Date(Web):November 4, 2016
DOI:10.1021/acs.jpcc.6b09245
Metal–semiconductor heteronanostructures have attracted increasing attention due to the strong interactions between the two nanoscale-spaced components. Herein, a steerable hydrothermal method is used to control the growth of Ag2S shells onto Au nanotriangles with tunable plasmon resonance and local field distribution. Through adjusting pH value and sulfur source, three types of Au/Ag2S heteronanostructures are obtained, including shells on the tips (Au/Ag2S (tips)), shells on the sides (Au/Ag2S (sides)), and complete shells (Au@Ag2S). The surface plasmon resonance and local field confinement are demonstrated to vary with the shell position. Furthermore, compact CdS nanoshells are coated onto the Au@Ag2S without any shape change of Au cores. By testing the photodegradation rate of Rhodamine B (RhB) under visible-light irradiation, the Au@Ag2S@CdS hybrids exhibit enhanced photocatalytic activity compared with Au@CdS and CdS. The strong local electric field, the enhanced visible-light absorption, and the optimum band arrangement between Ag2S and CdS are thought to be the main factors.
Co-reporter:Liang Ma;Shan Liang;Xiao-Li Liu;Da-Jie Yang;Qu-Quan Wang
Advanced Functional Materials 2015 Volume 25( Issue 6) pp:898-904
Publication Date(Web):
DOI:10.1002/adfm.201403398
The metallic nanostructures with unique properties of tunable plasmon resonance and large field enhancement have been cooperated with semiconductor to construct hetero-nanostructures for various applications. Herein, a general and facile approach to synthesize uniform dumbbell-like gold–sulfide core–shell hetero-nanostructures is reported. The transformation from Au nanorods (NRs) to dumbbell-like Au NRs and coating of metal sulfide shells (including Bi2S3, CdS, CuxS, and ZnS) are achieved in a one-pot reaction. Due to the reshaping of Au core and the deposition of sulfide shell, the plasmon resonances of Au NRs are highly enhanced, especially the about 2 times enhancement for the visible transverse plasmon resonance compared with the initial Au NRs. Owing to the highly enhanced visible light absorption and strong local electric field, we find the photocatalytic activity of dumbbell-like Au–Bi2S3 NRs is largely enhanced compared with pure Bi2S3 and normal Au–Bi2S3 NRs by testing the photodegradation rate of Rhodamine B (RhB). Moreover, the second-layer sulfide can be coated and the double-shell Au–Bi2S3–CdS hetero-nanostructures show further improved photodegradation rate, especially about 2 times than that of Degussa P25 TiO2 (P25) ascribing to the optimum band arrangement and then the prolonged lifetime of photo-generated carriers.
Co-reporter:Si-Jing Ding, Shan Liang, Fan Nan, Xiao-Li Liu, Jia-Hong Wang, Li Zhou, Xue-Feng Yu, Zhong-Hua Hao and Qu-Quan Wang
Nanoscale 2015 vol. 7(Issue 5) pp:1970-1976
Publication Date(Web):12 Dec 2014
DOI:10.1039/C4NR05731G
Doping with intentional impurities is an intriguing way to tune the properties of semiconductor nanocrystals. However, the synthesis of some specific doped semiconductor nanocrystals remains a challenge and the doping mechanism in this strongly confined system is still not clearly understood. In this work, we report, for the first time, the synthesis of stable and water-soluble Ag-doped CdTe semiconductor quantum dots (SQDs) via a facile aqueous approach. Experimental characterization demonstrated the efficient doping of the Ag impurities into the CdTe SQDs with an appropriate reaction time. By doping 0.3% Ag impurities, the Stokes shift is decreased by 120 meV, the fluorescence intensity is enhanced more than 3 times, the radiative rate is enhanced 4.2 times, and the non-radiative rate is efficiently suppressed. These observations reveal that the fluorescence enhancement in Ag-doped CdTe SQDs is mainly attributed to the minimization of surface defects, filling of the trap states, and the enhancement of the radiative rate by the silver dopants. Our results suggest that the silver doping is an efficient method for tuning the optical properties of the CdTe SQDs.
Co-reporter:Ya-Fang Zhang, Da-Jie Yang, Jia-Hong Wang, Ya-Lan Wang, Si-Jing Ding, Li Zhou, Zhong-Hua Hao and Qu-Quan Wang
Nanoscale 2015 vol. 7(Issue 18) pp:8503-8509
Publication Date(Web):13 Apr 2015
DOI:10.1039/C5NR00051C
Strong coupling of plasmons and molecules generates intriguingly hybridized resonance. The IR-806 molecule is a near-infrared cyanine liquid crystal dye with multiple molecular bands and its tunable absorption spectrum varies dramatically with concentration. In this article, we investigate multiple hybridized resonances of the Au nanorods (AuNRs) strongly coupled to IR-806 molecules. Five hybridized resonance peaks are observed in the extinction spectra of the AuNR@IR-806 hybrids. Two resonance peaks at approximately 840 and 912 nm in the hybrids are reported for the first time. The dependence of the multiple hybridized peaks on the bare plasmon resonance wavelength of AuNRs and the molecular concentration is also demonstrated. The observations presented herein provide a plasmon–molecule coupling route for tuning optical responses of liquid crystal molecules.
Co-reporter:Zi-Qiang Cheng, Fan Nan, Da-Jie Yang, Yu-Ting Zhong, Liang Ma, Zhong-Hua Hao, Li Zhou and Qu-Quan Wang
Nanoscale 2015 vol. 7(Issue 4) pp:1463-1470
Publication Date(Web):01 Dec 2014
DOI:10.1039/C4NR05544F
Seeking plasmonic nanostructures with large field confinement and enhancement is significant for photonic and electronic nanodevices with high sensitivity, reproducibility, and tunability. Here, we report the synthesis of plasmonic arrays composed of two-segment dimer nanorods and coaxial cable nanorods with ∼1 nm gap insulated by a self-assembled Raman molecule monolayer. The gap-induced plasmon coupling generates an intense field in the gap region of the dimer junction and the cable interlayer. As a result, the longitudinal plasmon resonance of nanorod arrays with high tunability is obviously enhanced. Most interestingly, the field enhancement of dimer nanorod arrays can be tuned by the length ratio L1/L2 of the two segments, and the maximal enhancement appears at L1/L2 = 1. In that case, the two-photon luminescence (TPL) of dimer nanorod arrays and the Raman intensity in the dimer junction is enhanced by 27 and 30 times, respectively, under resonant excitation. In the same way, the Raman intensity in the gap region is enhanced 16 times for the coaxial cable nanorod arrays. The plasmonic nanorod arrays synthesized by the facile method, having tunable plasmon properties and large field enhancement, indicate an attractive pathway to the photonic nanodevices.
Co-reporter:Da-Jie Yang;Zhong-Jian Yang;Ying-Ying Li;Zhong-Hua Hao
Plasmonics 2015 Volume 10( Issue 2) pp:263-269
Publication Date(Web):2015 April
DOI:10.1007/s11468-014-9804-2
Tunable Fano resonances in the gold rod-ring plasmonic nanocavities with strong coherent coupling are demonstrated by finite-difference time-domain (FDTD) method. For one rod-one ring nanocavity, symmetry breaking activates the high-order plasmon modes in the ring and causes a Fano resonance with a dip in the extinction spectrum of the cavity by the coherent coupling between the bright rod mode and dark ring mode. The addition of a non-resonant rod introduces a second dark mode, which could be successively excited by the first dark ring mode, and produces double Fano resonances. By adjusting the rod number and configuration of the nanocavity, the extinction line shape can be controlled and the near-field distribution can be dramatically modified. An intriguing phenomenon of superposition beats in the plasmon damping process is revealed, which induces an energy swap between the rod and ring. The antenna effect of the resonant rod as well as the energy transfer and distribution in the nanocavities are also discussed.
Co-reporter:Jiahong Wang;Hao Huang;Daquan Zhang;Ming Chen;Yafang Zhang;Xuefeng Yu
Nano Research 2015 Volume 8( Issue 8) pp:2548-2561
Publication Date(Web):2015 August
DOI:10.1007/s12274-015-0761-7
The nanoscale core/shell heterostructure is a particularly efficient motif to combine the promising properties of plasmonic materials and rare-earth compounds; however, there remain significant challenges in the synthetic control due to the large interfacial energy between these two intrinsically unmatched materials. Herein, we report a synthetic route to grow rare-earth-vanadate shells on gold nanorod (AuNR) cores. After modifying the AuNR surface with oleate through a surfactant exchange, well-packaged rare-earth oxide (e.g., Gd2O3:Eu) shells are grown on AuNRs as a result of the multiple roles of oleate. Furthermore, the composition of the shell has been altered from oxide to vanadate (GdVO4:Eu) using an anion exchange method. Owing to the carefully designed strategy, the AuNR cores maintain the morphology during the synthesis process; thus, the final Au/GdVO4:Eu core/shell NRs exhibit strong absorption bands and high photothermal efficiency. In addition, the Au/GdVO4:Eu NRs exhibit bright Eu3+ fluorescence with quantum yield as high as ~17%; bright Sm3+ and Dy3+ fluorescence can also be obtained by changing the lanthanide doping in the oxide formation. Owing to the attractive integration of the plasmonic and fluorescence properties, such core/shell heterostructures will find particular applications in a wide array of areas, from biomedicine to energy.
Co-reporter:Fan Nan;Shan Liang;Jia-Hong Wang;Xiao-Li Liu;Da-Jie Yang;Xue-Feng Yu;Zhong-Hua Hao ;Qu-Quan Wang
Advanced Optical Materials 2014 Volume 2( Issue 7) pp:679-686
Publication Date(Web):
DOI:10.1002/adom.201400034
Metal/semiconductor Au/Ag2S core/shell hetero-nanorods with controlled morphology are synthesized and their tunable plasmon enhancements (involving linear and nonlinear optical processes) are demonstrated. The synthesis involves site-selective deposition of Ag layer onto Au nanorod seeds, followed by site-selective sulfuration of the Ag layer, resulting in three types of Au/Ag2S core/shell nanorods with complete, corner-opened, or end-opened shells. The plasmon resonance and local field confinements varing with shell morphology are analyzed using FDTD calculations. Nonlinear measurements reveal that the Ag2S shell with appropriate morphology leads to the nonlinear refraction and saturable intensity of the Au nanorods increasing 7.6 and 4.1 times, respectively, which indicates strong plasmon enhancements and energy relaxation in the Au/Ag2S core/shell nanorods. This site-selective shell growth strategy offers a constructive bottom-up approach to maneuver the optical properties of plasmonic nanocrystals for various applications.
Co-reporter:Xiao-Li Liu ; Jia-Hong Wang ; Shan Liang ; Da-Jie Yang ; Fan Nan ; Si-Jing Ding ; Li Zhou ; Zhong-Hua Hao ;Qu-Quan Wang
The Journal of Physical Chemistry C 2014 Volume 118(Issue 18) pp:9659-9664
Publication Date(Web):April 21, 2014
DOI:10.1021/jp500638u
Localized surface plasmon resonances (LSPRs) of metal nanostructures are highly related to the shape, which could greatly enhance the light–matter interaction at nanoscale. Here, we investigate the LSPRs of gold nanostars corresponding to the unique morphology and demonstrate surface-enhanced Raman scattering (SERS) activities and nonlinear refraction properties of two typical structures. By adjusting the synthesis condition, the main plasmon resonance could be tuned from 557 to 760 nm. The plasmon modes and intense field enhancement near the sharp tips are revealed by finite-difference timed-domain (FDTD) simulations. The nonlinear refractive index |γ| reaches to the maximum value when the excitation wavelength is resonant to the LSPRs wavelength. The maximum value of |γ| for long-branched nanostars (λSP = 706 nm) is 5.843 × 10–4 cm2/GW, which is about 1.5 times larger than that of spherical-like nanostars with λSP = 563 nm. The SERS activity of long-branched nanostars is about 15 times larger than that of spherical-like gold nanostars.
Co-reporter:Xiao-Li Liu, Shan Liang, Fan Nan, Zhong-Jian Yang, Xue-Feng Yu, Li Zhou, Zhong-Hua Hao and Qu-Quan Wang
Nanoscale 2013 vol. 5(Issue 12) pp:5368-5374
Publication Date(Web):02 Apr 2013
DOI:10.1039/C3NR01170D
We report the synthesis of 43-nm diameter Au nanocube dimers by using Ag+ ions as competitive ligands to freeze L-cysteine-induced assembly process of the nanocubes to a desirable stage. Ascribed to the resonant interparticle coupling with an newly arising plasmon band at 710 nm and local field enhancement, the two-photon luminescence intensity of the Au nanocube dimers in solution was over 20 times stronger than that of the monomers in the wavelength range 555–620 nm. Furthermore, by coupling Raman tags onto the nanocube surface, a solution-based surface-enhanced Raman scattering (SERS) of the nanocube dimers had an enhancement factor of over 10 times compared to the isolated nanocubes. To sum up, with high stability in solution and attractive optical properties, the Au nanocube dimers have potential applications in in vivo bio-imaging and solution-based SERS.
Co-reporter:Jie Zhu;Junjun Shi;Yueyue Pan;Xiaoli Liu
Wuhan University Journal of Natural Sciences 2013 Volume 18( Issue 6) pp:530-534
Publication Date(Web):2013 December
DOI:10.1007/s11859-013-0968-y
We described a method for the rapid synthesis of uniform silver nanoparticles (NPs) under microwave heating, using poly(ethylene glycol) (PEG) as reducing agent and solvent and poly(vinylpyrrolidinone) (PVP) as capping agent. The transmission electron microscopy (TEM) and UV-Vis extinction spectra were used to characterize the size and uniformity of the silver NPs. At the same reaction temperature, the products with microwave heating were more uniform than that with oil heating. We also investigated the influence of reaction temperature, microwave power, and molar ratio of PVP to AgNO3. In our experiments, uniform silver NPs with mean diameter of 50 nm were synthesized at 140 °C under 700 W microwave irradiation with PVP/AgNO3 molar ratio of 5:1.
Co-reporter:Ling Li;Xiaolan Liu;Xiaoli Liu
Wuhan University Journal of Natural Sciences 2011 Volume 16( Issue 3) pp:241-244
Publication Date(Web):2011 June
DOI:10.1007/s11859-011-0743-x
Cadmium sulfide (CdS) nanowires were synthesized on Cd foil via a simple solvothermal reaction at 180 °C using thiosemicarbazide as the sulfide source and ethylenediamine as the solvent. The CdS nanowires are hexagonal-phase single crystals with an average diameter of 50 nm and length of several microns. The as-prepared CdS nanowires show an absorption peak of around 483 nm in the absorption spectrum. The CdS nanowires exhibit bright photoluminescence (PL) with two distinct emission bands at 503 nm and 697 nm, which shows that the as-prepared CdS nanowires are high-quality nanocrystals.
Co-reporter:Zhang-Kai Zhou, Min Li, Zhong-Jian Yang, Xiao-Niu Peng, Xiong-Rui Su, Zong-Suo Zhang, Jian-Bo Li, Nam-Chol Kim, Xue-Feng Yu, Li Zhou, Zhong-Hua Hao, and Qu-Quan Wang
ACS Nano 2010 Volume 4(Issue 9) pp:5003
Publication Date(Web):August 25, 2010
DOI:10.1021/nn100578b
Efficient plasmon-mediated excitation energy transfer between the CdSe/ZnS semiconductor quantum dots (QDs) across the silver nanowire array up to 560 nm in length is observed. The subwavelength imaging and spectral response of the silver nanowire arrays with near-field point-source excitations are revealed by theoretical simulations. Our studies demonstrate three advantages of the nanosystem: efficient exciton−plasmon conversion at the input side of the array through near-field strong coupling, directional waveguidance and resonant transmission via half-wave plasmon modes of the nanowire array, and subwavelength imaging at the output side of the array. These advantages allow a long-range radiative excitation energy transfer with a high efficiency and a good directionality.Keywords: radiative energy transfer; semiconductor quantum dots; silver nanowire array; subwavelength imaging; surface plasmon
