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Composite nanomaterials have recently amassed increasing interests in biomedical applications because of the limited function of pure material. This work designed a uniform and multifunctional nanoplatform (NPF) probe composed of superparamagnetic ferroferric oxide (Fe3O4) cluster as core and mesoporous silica embedded with CdTeS quantum dots (QDs) as middle layer wrapped by the outer silica shell. The Fe3O4 cluster core served as the magnetic and photothermal agent, and the CdTeS QDs served as the fluorescence-labelling agent. For the first time, quantities of QDs were embedded into the mesoporous silica based on electrostatic interaction and physical absorption, which are superior to the traditional crosslink-loading method. The NPF probes were successfully internalized into cancer cell with the decoration of folic acid. Transmission electron microscopy (TEM), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), fluorescence spectrophotometer, and temperature detector were used to detect the NPF probe. The NPF probe was verified to possess excellent magnetic, fluorescent, and photothermal properties suitable for multiple medical applications. More importantly, a collaborative diagnosis–treatment probe that combines fluorescence labelling and photothermal therapy exhibited the perfect behaviour of labelling and destroying cancer cells in vitro.

A biocompatible, nontoxic theranostic nanoplatform consisting of mesoporous silica-coated ferroferric oxide (Fe3O4) and Mn-doped ZnS-ZnS quantum dots has been synthesized via a layer-by-layer method. Transmission electron microscopy, X-ray diffractometer, magnetometry, and fluorophotometer were employed to characterize the nanoplatform. The nanoplatform exhibited excellent superparamagnetic, fluorescent and light adsorption properties. A template method was introduced to form a mesoporous silica structure on the nanoplatform, lowering the mass of the nanoplatform and effectively promoting the absorption of incident light, compared with traditional silica layer. In addition, after endocytosis of the nanoplatform, cancer cells were easily detected under fluorescence microscope because of the excellent fluorescent behavior of quantum dos. Moreover, vitro cell experiments confirmed that nanoplatform possessed perfect photothermal effect to destroy tumor cells under the laser irradition. Therefore, ferroferric oxide/quantum dots nanoplatforms, combined with fluorescent labeling and photothermal therapy for cancer cells, are expected to be a promising biopotential materials in the field of diagnosis and treatment.

Despite the fact that Co3O4 nanomaterials have gained much attention due to their excellent electrochemical properties, the poor conductivity and catalytic reduction ability for I3− ion hinder their application as counter electrode (CE) of dye sensitized solar cells (DSSCs). Herein, a facile ion exchange approach is developed to prepare S-doped Co3O4 nanosheet. S doping strategy significantly improves the catalytic activity of Co3O4 nanosheets for the reduction of I3− ion and their charge transport ability. For the sake of doping S into Co3O4 and rGO simultaneously, the similar wet chemical process is adopted in the presence of graphene oxide (GO) to synthesize S-doped Co3O4/reduced graphene oxide (rGO) composites. The power conversion efficiency (PCE) of Co3O4-DSSC is only 1.98%. Using S-doped Co3O4 as CE, the PCE can be dramatically improved to 6.76%. Moreover, the S-doped Co3O4/rGO-DSSC shows higher PCE (8.24%) than that of Pt (7.79%). Electrochemical measurement results indicate that the S-doped Co3O4/rGO composites not only show excellent electrocatalytic activity, but also show high cycling stability. The outstanding improved performance of DSSCs with S-doped Co3O4 nanosheet and S-doped Co3O4/rGO composite as CEs demonstrates that the surface atomic configurations of CE materials have significant influence on their electrocatalytic activity.

Branched β-NaLuF4: Yb/Er was synthesized using a simple hydrothermal method by controlling the NaF/Ln molar ratio. In contrast to the β-NaYF4: Yb/Er hexagonal disks, the branched β-NaLuF4: Yb/Er has stronger emission intensity. The integrated intensities of green and red emission bands were as 6.2 and 3.3 times as that of NaYF4, respectively. The branched β-NaLuF4: Yb/Er has the smaller unit cell volume, the higher absorption intensity around 980 nm and the lower crystal field symmetry than NaYF4, which made a significant contribution to the stronger upconversion (UC) fluorescence emissions. The results indicate that the branched β-NaLuF4: Yb/Er is an excellent UC luminescence material. The current research has a great potential in improving near-infrared conversion efficiency of solar cells.

Ag nanobox/silica/quantum dot (QD) nanoprobe was synthesized by using a hydrothermal method to investigate the interaction between Ag nanobox and CdTeS QDs for the first time. Finite-difference time domain method was used to compare the optical behavior of Ag nanobox with Ag nanosquare. The comparison demonstrated that the Ag nanobox had excellent optical characteristics. In the nanoprobe, the silica shell was used to adjust the distance between the Ag nanobox and CdTeS QDs. A 4.5-fold increase in the fluorescence intensity of CdTeS QDs was achieved based on the local surface plasmon resonance (LSPR) of Ag nanobox. The Ag nanobox/silica/CdTeS QD nanoprobe was used to label cancer cells, thereby indicating that the nanoprobe was a suitable and excellent fluorescence probe.

Electrodeposition is of great interest for a large number of applications, especially in low-cost thin film solar cells. In this work, Cu 2 O films were electrodeposited firstly with potentiostatic and galvanostatic modes, respectively. The trends of current density and applied potential were systematically studied in the deposition process, and some drawbacks were revealed within the two deposition modes. In order to remove the drawbacks, potentiostatic and galvanostatic two-step electrodeposition was developed to prepare Cu 2 O films. The optical absorption and surface photovoltage properties of the prepared Cu 2 O films were studied. Finally, the two-step electrodeposition was used to construct Cu 2 O based solar cells. The two-step electrodeposition will be an optimized method to construct high-quality semiconductor film based solar cells.

Lead halide perovskites have attracted much attention following their successful use in photovoltaic devices with impressive power-conversion efficiencies. Owing to perovskite quantum dots’ ionic nature, the surface ligands are easy to be overdamaged in polar solvents. Thus, there have been some difficulties in protecting the surface ligands of the quantum dots during purification processes, especially in solvent reprecipitation techniques. Here, we used mixtures of ethyl acetate and methyl acetate during the purification process to precipitate perovskite quantum dots that showed scarcely any damage to their surface ligands; furthermore, these purified CsPbBr3 quantum dots displayed high performances in devices. Quantum dot films were prepared via spin-coating from solution for use in solar cells with a simple structure (indium tin oxide/ZnO/quantum dots/Au), which displayed power-conversion efficiencies of up to 2.43%. Multiple purification cycles of this purification process allowed us to obtain near-perfectly modified perovskite colloidal quantum dots, ideal for application in optoelectronic devices.

First-principles calculations based on periodic density functional theory (DFT) have been used to investigate the geometries, electronic structures, magnetic properties and diffusion behaviors of different noble metal adatoms (Pd, Pt, Cu, Ag and Au) on MoS2 monolayers. The results demonstrate that these adatoms can chemically adsorb on MoS2 monolayers. The band gaps of MoS2 monolayers with a Pd or Pt atom adsorbed are reduced owing to impurity states that emerge simultaneously within the gap region of the pristine MoS2 monolayer. The unpaired electrons in MoS2 monolayers with a Cu, Ag or Au atom adsorbed are spin polarized, resulting in total magnetic moments of 1.0 μB per supercell, which is caused by the strong hybridization between the metal adatoms and surrounding Mo or S atoms. Long-range antiferromagnetic (AFM) coupling has been observed between group IB metal adatoms. Due to charge transfer between adatoms and the MoS2 host, the work functions were modulated upon adsorption of noble metals. In addition, the diffusion behaviors of noble metal adatoms on the MoS2 monolayer suggest that Cu, Pd and Pt atoms favor the formation of a metal nanotemplate on the MoS2 monolayer, and Ag and Au are likely to form isolated particles in the initial growth stage. These findings may provide useful guidance to extend the potential applications of MoS2 in low-dimensional nanoelectronic and spintronic devices.

In this work, the geometry, stability and electronic structures of atomic palladium chains supported on the NiAl(1 1 0) surface have been investigated by using the first-principles calculations. Palladium monomer strongly adsorbed at Ni Ni and Al Al bridge sites bonding with the two most neighboring Ni atoms. There is competitive mechanism between interactions of Pd Pd and interactions between Pd and NiAl substrate for Pd ad-chains. We also observe the interactions of resonance states give rises to a band of resonance states, which is mainly related to the overlap of 5sp orbital of adjacent Pd atoms. Finally, we demonstrated that the atomic spacing in Pd ad-chains and adsorption sites had significant influences to the bandwidth of resonance band. These results may have potential applications in the fields of nanoelectronics and nanoscale catalysts.

We theoretically calculate the resonant (1 + 1) two photon transition probability in the Rubidium (Rb) atom by the θ − phase shaped pulses. The results show that the resonant two photon transition probability can be enhanced by the θ − phase shaped pulses. The resonant two photon transition amplitude in complex plane have different distributions for different phase step position, but those distributions meet in a point which corresponds the transition amplitude of transitions-limited pulse and the shaped pulses with θ = 0. Moreover, the transition amplitude of on-resonant and near-resonant part is calculated to explain the two photon transition amplitude distribution and reveal the physical control mechanism.

In this work, the optical characteristics of electrodeposited Cu2O films was studied, and the depth of photogenerated carriers in Cu2O films was obtained. In order to improve the collection depth of the photogenerated carrier in ZnO/Cu2O solar cells, ZnO nanorod array were employed to construct composite-structure solar cells. The influence of the ZnO nanorod arrays on short-circuit current and open circuit voltage was systematically analyzed in the nanorod cells. For optimizing device performance, ordered ZnO nanorod arrays that incorporated design spacing that matched the carrier diffusion length of the absorption layer were used. Analyses of the photovoltaic properties revealed that ordered nanorod arrays with a proper spacing could improve carrier generation efficiency in high-efficient collection regions of the carriers. These observations indicate that nanorod spacing is an important variable in the construction of high-efficient nanorod-based solar cells.

In this work, ZnO nanorod/Cu2O composite nanostructure solar cells were prepared using hydrothermal growth and electrodeposition. The CdS layer was added between ZnO and Cu2O to suppress carrier reverse recombination. Nondestructive interface deposition methods were employed to prepare CdS and Cu2O functional layers. The CdS layers were unconventionally deposited in non-alkaline solution, which can inhibit etching on the ZnO surface, and Cu2O layers were electrodeposited in ZnO-buffered alkaline solution which can also inhibit etching on the ZnO surface. Finally, the performance of solar cells was improved by adding a highly resistive CdS intermediate layer between ZnO and Cu2O layers. This work demonstrated the nondestructive interface approach of chemical solution deposition of functional layers on ZnO and possibilities for further improvements to the performance of Cu2O-based nanostructure solar cells with the addition of an intermediated layer.

In this paper, we theoretically demonstrate that the fine green emission in Er3+ ion system can be effectively controlled by the shaped ultra-short laser pulses with a π phase modulation. Our results show that the two photon transition probabilities of two excited states are effectively tuned by the single π phase modulation of 800 nm or 1600 nm laser pulses. By combining π phase modulation of the two exciting pulses, one excited state can be populated at maximum value, while the other state population can be widely tuned from zero to the maximum value. Furthermore, we explain the physical control mechanism of fine green emission by considering the second-order power spectrum of the shaped pulses. These schemes can be applied to realize the selective population of multiple excited states.

Water-soluble ZnS:Mn quantum dots (QDs) were synthesized using a hydrothermal method with 3-mercaptopropionic acid as stabilizer. The optical properties of ZnS:Mn QDs were thoroughly investigated by tuning the doping concentration of Mn2+ and the Zn/S precursor ratio, to obtain an optimal parameter for QDs with excellent fluorescence characteristics. ZnS:Mn QDs excited at only one wavelength, however, which seriously limited their further application. Here, a trace Cd ion was doped into a ZnS host, resulting in QD excitation covering a wide adjustable waveband. Furthermore, when a ZnS shell was coated onto the surface of the ZnCdS:Mn QDs, photoluminescence intensity and stability were further enhanced. After coupling with an anti-CK 19 antibody, the ZnCdS:Mn/ZnS core/shell QDs were able to function by labeling cancer cells, indicating that they could be considered as a suitable bio-probe for cells and tissue imaging.

First-principles calculations based on periodic density functional theory (DFT) have been used to investigate the geometries, electronic structures, magnetic properties and diffusion behaviors of different noble metal adatoms (Pd, Pt, Cu, Ag and Au) on MoS

Hot spots have been considered as a dominant role in surface enhancement Raman scattering (SERS). Here, we investigated the size and shape effect of Ag nanocubes in surface plasmon response and SERS by both experiment and theory simulation method. Silver nanocubes with abundant “hot spots” were synthesized by a polyol method and utilized as electrodes for achieving high SERS enhancement. The absorption wavelengths of the nanocubes were tunable by changing the edge lengths of the nanoparticles. Finite-difference time-domain (FDTD) simulations were employed to investigate the local E-field generation around silver (Ag) nanocubes indicating remarkable E-field enhancement at the edges and vertexes known as “hot spots”. Then, the SERS analyses demonstrated that the SERS activity of various Ag nanocubes using crystal violet (CV) as probe molecules showed a significant enhancement. The enhancement factors of SERS show strong sensitivity between the nanoparticle size and shape. Moreover, the enhancement for CV on Ag nanocubes was significantly higher than for Ag nanospheres. Therefore, the stable and high-performance of Ag nanocubes SERS system shows great application prospects in both scientific researches and practical application.

Photoanode is a critically important component in quantum dot sensitized solar cell (QDSC), and its configuration will exert a tremendous influence on the cell performance. In this paper, submicrometer-sized mesoporous TiO2 beads were prepared for QDSC application in view of their high specific surface area, superior light scattering and easy electrolyte penetration. Two configurations for the photoanodes were designed and studied with mesoporous TiO2 beads combined with nanoparticles: a double-layer configuration composed of a thick bead layer on top of a thin nanoparticle layer, and a mixture structure made of mixed mesoporous TiO2 beads and nanoparticles. Photovoltaic results showed that double-layer and mixture configurations delivered power conversion efficiencies of 4.33% and 4.65%, respectively, achieving impressive improvement compared to the single-layer films made from mesoporous beads or nanoparticles (∼4%). The mesoporous TiO2 beads served as scattering layer or scattering centers to enhance light scattering and boost the photocurrent while the incorporation of nanoparticles into the voids between mesoporous beads further increased the surface area for QD loading and led to better connection between the neighboring beads. Electrochemical impedance spectroscopy analysis revealed a retarded charge recombination for the mesoporous beads when combined with nanoparticles, reflected in the increase of open circuit voltage.

Hydrofluoric acid (HF)-assisted one-step synthesis of pompon-like/chip-like FeSe2 particles by a solvothermal method has been studied for the first time in this paper. By adjusting the dosage of HF used, FeSe2 particles with pompon-like and chip-like morphologies were obtained. The reaction mechanism was presented based on the experimental phenomena, and the roles played by HF in the synthesis were clearly explained, proving that HF had a significant influence on controlling the morphologies of the FeSe2 particles. By altering the iron sources without changing any other conditions (similar experimental results were observed). We further demonstrated that this method was universally applicable. The wettability and light-trapping effects of the pompon-like/chip-like particles were also investigated, respectively. After modification with heptadecafluorodecyltrimethoxy-silane (HTMS), the pompon-like particles exhibited excellent superhydrophobic/superoleophobic (superamphiphobic) properties with water/oil contact angle of about 156.0°/154.6° and water/oil sliding angle of about 2.0°/5.0°. Ultralow reflectance of the samples (lower than 3%) in the entire wavelength range of 300–1800 nm was also observed in our experiments. Utilizing HF to control the morphologies of FeSe2 particles is an innovative attempt and is expected to show promising potential in controlling the morphologies of other transition metal chalcogenides.

Au nanoparticle@SiO2@CdTe/CdS/ZnS quantum dot (QD) composite structures were synthesized by a liquid phase synthesis method. In this paper, three steps were adopted to gradually grow PVP-stabilized Au seeds from which PVP-stabilized Au nanoflower (NF) structures were successfully synthesized. For the sake of controlling the distance between Au NFs and QDs, silica was used as the shell material for coating Au NFs. The applications of this multi-functional nanoprobe in photothermal treatment and bio-labeling were demonstrated on MCF-7 and MDA-MB-231 breast cancer cells labeled with Au NF@SiO2@QDs. The experimental results of viability staining indicate that Au NF@SiO2@QDs composites with an excitation threshold of the photothermal effect of only 1.0 W cm−2 exhibit excellent photothermal conversion efficiency owing to the large absorption cross sections of Au NFs. Compared with that of pure QDs, the fluorescence efficiency of Au NF@SiO2@QDs was increased by 40%, which could be attributed to localized surface plasmon enhanced dipole radiation. Fluorescence imaging results reveal that Au NF@SiO2@QDs targeted the membrane of cancer cells showing strong fluorescence. Therefore, it can be concluded that the composite structure combines the therapeutic and diagnostic modalities.

Enhancement of the light emission of dye molecules ( Ru ( bpy ) 3 2 + ) was studied by coating dye-doped SiO2 layer on Ag core. The enhancement ratio was found to be relative to the thickness of dye-doped silica layer. The core–shell Ag@dye-SiO2 nanocomposites have the strongest fluorescence intensities when the thickness of dye-SiO2 layer was tuned to 10 nm. It was found that an 11-fold enhancement of fluorescence signal was realized with Ag@dye-SiO2 nanoparticles, compared to the sample without silver core.

A multifunctional mesoporous, magnetic and fluorescent Fe3O4/SiO2/CdTe nanoprobe with well-defined core–shell nanostructures was prepared. This multifunctional nanoprobe was synthesized through a novel method mainly including two steps. The first step involved the controlled growth of mesoporous silica layer onto the surface of Fe3O4 nanoparticle using tetraethyl orthosilicate as silica source, cationic surfactant cetyltrimethylammonium bromide as template, and 1,3,5-triisopropylbenzene as pore swelling agents. The second step involved the layer-by-layer assembly of 3-aminopropyltrimethoxysilane and fluorescent CdTe quantum dots with the mesoporous Fe3O4/SiO2 nanoparticles. The well-designed nanoprobe exhibits strong excitonic photoluminescence and superparamagnetism at room temperature. In attention, the mesoporous silica layer of the nanoprobe with great loading capacity makes it a promising candidate as targeted drug delivery platform.

An electrolysis method for preparation of Ag nanoparticle (NP) films on the transparent conductive substrates was developed. The morphologies and sizes of Ag NPs can be controlled by the electrolysis time and thermal treatment modes. The enhancement of photoluminescence from CdSe quantum dots due to the localized surface plasmons (LSPs) of Ag nanoparticles was also investigated. The strongest enhancement is as high as 10 times. Additionally, the effect of thermal treatment process, including the rapid thermal treatment and slow thermal process, on the morphology of the Ag nanoparticle was also studied. The result shows that the slow thermal treatment process would be favorable for the formation of larger Ag NPs and increasing the ratio of worm-like Ag NPs, which contain most of the “hot spots”, increases the quantum yields of LSPs.

In this work, Ag nanoparticle/Ag-doped SiO2composite films were prepared with AgNO3and tetraethoxysilane precursors through a simple and environmentally friendly sol–gel method under high annealing temperatures. The effect of different annealing temperatures (400[Formula: see text]C, 500[Formula: see text]C, 600[Formula: see text]C, and 700[Formula: see text]C) on the structural and optical characters of the composite films was investigated. The localized surface plasmon resonance (LSPR) effect of the Ag nanoparticle/Ag-doped SiO2composite films enhanced the fluorescence intensity of CdSe quantum dots (QDs). Scanning electron microscopy (SEM), UV-vis spectrophotometer and photoluminescence (PL) spectroscopy were used to characterize the morphology and optical properties of the composite nanostructure.

The morphology, stability and electronic properties of Pd and Au monolayers supported by MoS2 substrate have been investigated by using the first principles calculations based on periodic density functional theory (DFT). The results demonstrated that the most stable site is top of Mo top of S ([Formula: see text]) for the adsorption of Pd and Au monolayers on MoS2. We found that Pd/MoS2 with lower adsorption energy of [Formula: see text]0.54[Formula: see text]eV is energetically more stable than Au/MoS2. Due to the emergence of impurities state in the bandgap of MoS2, Pd/MoS2 and Au/MoS2 display metallic character upon coating of metal monolayers. We demonstrated that the Pd monolayer strongly hybrids with underlying Mo and S around the Fermi level, which is achieved by the intermediate Pd–S–Mo hybridized chains. On the contrary, intensity of impurities states around the fermi level is much weaker for Au/MoS2, which can be explained by weak hybridizations between sp state of Au and 4[Formula: see text] state of nearest neighboring Mo. The calculated results demonstrated that work functions are markedly modulated to 4.99 and 6.23[Formula: see text]eV after coating of Pd and Au monolayer, respectively, which can be qualitatively explained by the fact that Pd (as accepter) received charge from the MoS2 host, while Au donated charge to the host. These findings promise potential applications in the fields of nanoelectronics in future, such as it's helpful to choose suitable electrode materials for MoS2-based nanodevices.

Analytically discussed is the dynamical properties of the spiraling elliptic beams in nonlocal nonlinear media. This class of spiraling elliptic beams carry the orbital angular momentum (OAM), and can rotate on the cross section perpendicular to the propagation direction during the propagations. The optical intensity, the beam width, and specially the angular velocity are both analytically and numerically discussed in details. We shown that both the deviations from the critical power and the deviations from the critical OAM can make the spiraling elliptic beams breathe. The decrease (increase) of the OAM or the increase (decrease) of the power can both make the spiraling elliptic breathers contract (diffract), however, there still exist differences between them. The rotating speed can be changed by the input optical power or the input OAM, which may have potential applications in the controlling of the optical beams.

A novel class of cell probe structured as gold nanostar@SiO2@CdTeS quantum dots@SiO2 nanoprobes with multifunctional (MFNPs) fluorescent and photothermal properties were demonstrated. The MFNPs with good homogeneity (129 ± 10 nm) and dispersity were synthesized by a liquid phase method. The fluorescence signal of quantum dots was enhanced in the MFNPs, compared with the pure quantum dots. The vitro study showed that the MFNPs can realize the targeted labeling after functionalized with anti-body. Furthermore, the nanoprobe displays strong surface plasmonic resonance absorbance in the near-infrared region, thus exhibiting an NIR (808 nm)-induced temperature elevation. When cancer cells were cultured with the anti-body linked MFNPs and irradiated by laser, the MFNPs were demonstrated as good candidates for curing cancer cells. Therefore, such a multifunctional probe can be developed as a promising nanosystem that integrates multiple capabilities for effective cancer diagnosis and therapy.

The coupling of local surface plasmon (LSP) of nanoparticle and surface plasmon (SP) mode produced by metal film can lead to the enhanced electromagnetic field, which has an important application in enhancing the fluorescence of quantum dots (QDs). Herein, the Ag nanocube and Ag film are used to enhance the fluorescence of CdSe QDs. The enhancement is found to relate to the sizes of the Ag nanocube and the thickness of the Ag film. Moreover, we also present the fluorescence enhancement caused by only SP. The result shows that the coupling between metal nanoparticles and metal film can realize larger field enhancement. Numerical simulation verifies that a nanocube can localize a strong electric field around its corner. All the results indicate that the fluorescence of QDs can be efficiently improved by optimizing the parameters of Ag film and Ag cubes.

A gold tetrahedral nanocage, i.e., a tetrananocage, that converts near-infrared (NIR) light into heat was fabricated by using a simple method. Silver tetrahedra with good homogeneity and dispersity were synthesized by a hydrothermal route. Gold tetrananocages were obtained using a galvanic replacement reaction between Ag tetrahedra and HAuCl4 solution. The surface plasmon resonance (SPR) of gold tetrananocages was tuned from 412 nm to 850 nm through controlling the volume of HAuCl4 solution added. This Au tetrananocage can effectively convert NIR light into heat when the SPR couples with the exciting light. When cancer cells are cultured with the gold tetrananocages for several hours and irradiated, the gold tetrananocages destroy the cancer cells effectively and demonstrate themselves to be a good candidate for combating cancer.

A novel nontoxic, magnetic, and luminescent nanoprobe is prepared by using complex nanoparticles, which are composed of Fe3O4 nanoparticles and Mn-doped ZnS quantum dots (QDs). The nanocomposite probe can provide visible optical and magnetic resonance images simultaneously. Compared with the previously toxic cadmium and mercury based QDs, the superiority of the Mn-doped ZnS QDs is little virulence. The structure and the properties of the particles are characterized by energy dispersive X-ray analysis spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, photoluminescence spectroscopy, and vibrating sample magnetometer.