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Magnetic–plasmonic nanoparticles (NPs) have attracted great interest in many fields because they can exhibit more physical and chemical properties than individual magnetic or plasmonic NPs. In this work, we synthesized Au- or Ag-decorated Fe3O4 nanoparticles coated with PEI (Fe3O4-PEI-M (M = Au or Ag) NPs) using a simple method. The influences of the plasmonic metal NPs' (Au or Ag) coating density on the magnetic and plasmonic properties of the Fe3O4-PEI-M (M = Au or Ag) NPs were investigated, and the density of the plasmonic metal NPs coated on the Fe3O4 NPs surfaces could be adjusted by controlling the polyethyleneimine (PEI) concentration. It showed that the Fe3O4-PEI-M (M = Au or Ag) NPs exhibited both magnetic and plasmonic properties. When the PEI concentration increased from 5 to 35 mg/mL, the coating density of the Au or Ag NPs on the Fe3O4 NPs surfaces increased, the corresponding magnetic intensity became weaker, and the plasmonic intensity was stronger. At the same time, the plasmonic resonance peak of the Fe3O4-PEI-M (M = Au or Ag) NPs was red shifted. Therefore, there was an optimal coverage of the plasmonic metal NPs on the Fe3O4 NPs surfaces to balance the magnetic and plasmonic properties when the PEI concentration was between 15 and 25 mg/mL. This result can guide the application of the Fe3O4-M (M = Au or Ag) NPs in the biomedical field. [ABSTRACT FROM AUTHOR]

We designed a novel perovskite plasmonic nanolaser based on a semiconductor–graphene–insulator–metal (SGIM) structure in the visible region, and the graphene is placed between an inorganic CsPbBr3 nanowire and a semi-circular silver ridge substrate deposited with silicon dioxide (SiO2). Based on the finite element method, the influences of the graphene thickness and CsPbBr3 nanowire radius on the mode characteristics and electric field distribution of the hybrid plasmonic waveguide were investigated. We obtained the optimal structure parameter of the hybrid plasmonic waveguide, which could achieve a low gain threshold of 0.72 μm−1 in the visible region. Furthermore, compared to a gold or copper bridge substrate, the plasmonic waveguide based on the sliver bridge substrate exhibited a smaller propagation loss and larger propagation distance, leading to a lower gain threshold. This work provides us a novel method for developing applications of nanolasers in the visible region. [ABSTRACT FROM AUTHOR]

We reported on the enhanced lasing in organic dyes based on plasmonic hybrid structure of Ag nanoparticles (NPs)-Ag film, the diameters of Ag NPs ranged from 20 nm to 100 nm. The lowest lasing threshold was achieved by the optimal size Ag NPs-Ag film hybrid structure, which was reduced by 5.2 times than that of the neat gain medium. Comparing to the separate Ag NPs or Ag film, the hybrid structure presented the more intense local electric field due to the plasmonics coupling between the localized surface plasmons of Ag NPs and the surface plasmon polariton of Ag film, and the stronger scattering due to the reinjection of the leaking photons by external feedback of Ag film. The effects of different sizes Ag NPs-Ag film hybrid structures on lasing were investigated. It found that when the Ag NPs in hybrid structure is small (diameter≤40 nm), the enhanced localized electric field plays a major role on enhanced lasing; with the increase of Ag NPs size, the enhanced electric field and scattering have comparable contribution on enhancing lasing; for the larger size Ag NPs-Ag film (diameter≥80 nm), the scattering effect is the dominant mechanism for random lasing. Then the lowest threshold was dominated by the balance of enhanced localized electric field and scattering effect. Our results could provide us a unique idea to effectively enhance the lasing of organic dyes, and realize the lower pumped threshold and stronger lasing. [ABSTRACT FROM AUTHOR]

The movement of magnetic nanoparticles (NPs) can be controlled by an external magnetic field. And Fe 3 O 4 @M (M = Ag or Au) core-shell NPs can exhibit both magnetic and plasmonic properties simultaneously. In this article, we theoretically proposed a plasmonic coupled nanolaser with tunable wavelength in full visible light range based on Fe 3 O 4 @M (magnetic-plasmonic) core-shell NPs/metal film coupled structure. We investigated the optical properties of the plasmonic coupled nanolasers with different core-shell NP sizes and gap distances between Fe 3 O 4 @M NPs and metal film by the finite element method (FEM). By controlling the gap distance and NP size, the wavelength of the plasmonic nanolaser based on Fe 3 O 4 @Ag NPs/Ag film coupled structure could be tuned from 415 to 810 nm, and that based on Fe 3 O 4 @Au NPs/Au film could be tuned from 536 to 779 nm. This work provides us a theoretical basis to real-time tune the wavelength of the plasmonic coupled nanolaser based on a liquid gain environment under an external magnetic field. • Magnetic-plasmonic nanolaser based on a coupling between LSP and SPP was designed. • Fe 3 O 4 @M (M = Ag or Au) core-shell NPs/metal film coupled structure was developed. • Optical properties with different NP sizes and gap distances were studied. • SPASER wavelength can be tuned in a range of 40–98 nm by changing gap distance. • Wavelength tunable range was extended to full visible region by changing NP size. [ABSTRACT FROM AUTHOR]

We reported on the enhanced random lasing from organic dyes doped with silver nanoparticles (Ag NPs), the sizes of Ag NPs ranged from 8 nm to 250 nm. The effects of different sizes of Ag NPs on the lasing properties were studied. We found a strong dependence of the random lasing properties on the size of the Ag NPs, and the lowest threshold was achieved by the introduction of Ag NPs with the diameter of 150 nm. By studying the enhanced localized electromagnetic (EM) field due to localized surface-plasmon resonance and the scattering effect of Ag NPs in experiment and Mie theory, we found that the enhanced localized EM field plays a major role on enhanced lasing of organic dyes for the small Ag NPs (diameter < 50 nm); and the scattering effect is the dominant underlying mechanism for random lasing for the large Ag NPs (diameter ≥ 100 nm), which also suggest that the lowest threshold and strongest lasing are dominated by the photon scattering. [ABSTRACT FROM AUTHOR]

We propose a low threshold and wavelength tunable plasmonic coupled nanolaser based on a plasmonic coupling between Au nanosphere and Au film. By the finite-element method, we investigate the optical properties of the plasmonic coupled nanolaser with different nanosphere diameters and gap distances between Au nanosphere and Au film. The optical cross section of the plasmonic nanolaser based on the coupled nanostructure can be 60 times larger than that based on an independent Au nanosphere. And the corresponding gain threshold of the plasmonic coupled nanolaser is only 35% of that of the nanolaser with the independent Au nanosphere. This is attributed to that the coupled nanostructure exhibits a stronger electric field and optical intensity than the independent Au nanosphere, it can more effectively improve gain to compensate for metal loss. In addition, the plasmonic coupled nanolaser also exhibits a wavelength tunability in a wide spectral range by controlling the Au nanosphere diameter and gap distance between Au nanoparticle and Au film. This work can provide us an effective way to develop the on-chip application of nanolaser. • A plasmonic coupled nanolaser based on a coupling between LSP and SPP is designed. • The optical cross section is 60 times larger than that based on Au nanosphere. • The gain threshold is only 35% of that of nanolaser with independent Au nanosphere. • Coupled nanostructure exhibits a stronger electric field than Au nanosphere. • SPASER wavelength can be tuned by varying Au nanosphere diameter and gap distance. [ABSTRACT FROM AUTHOR]

[Display omitted] • A red emitter TPA-PFQ with a PLQY of 88.03% was synthesized. • TPA-PFQ was designed using 2-phenylbenzo[g]furo[2,3-b]-quinoxaline as acceptor. • The non-doped OLEDs gives an EQEmax of 2.09% and remained 2.03% at 5000 cd m−2. New emitters with deeply red emission and slow efficiency roll-off in non-doped organic light-emitting diodes (OLEDs) are highly expected. In this work, we used our recently developed 2-phenylbenzo[g]furo[2,3-b]-quinoxaline as the acceptor (A) and triphenylamine (TPA) as the donor (D), synthesized a D-A type red emitter, TPA-PFQ. The TPA-PFQ presented a high quantum yields of 88.03% in toluene solution. Using it as emitter, the non-doped OLEDs showed a saturated red emission with a peak of 620 nm and a maximum luminance of 11190 cd m−2. Moreover, the non-doped OLEDs presented a maximum EQE of 2.09% (2.47 cd A-1) at 100 cd m−2, and remained 2.0% (2.40 cd A-1) at 1000 cd m−2, 2.03% (2.49 cd A-1) at 5000 cd m−2, only 2.9% efficiency roll-off with the luminance changed from 100 cd m−2 to 5000 cd m−2. Our experiments demonstrated benzo[g]furo[2,3-b]quinoxaline skeleton could serve as a promising acceptor unit for constructing deep red emitters. [ABSTRACT FROM AUTHOR]

Metal films are extensively used as electrodes in optoelectronic devices. However, quenching caused by metal film is harmful to lasing and a main barrier to developing electrically pumped lasers. In this study, a dramatic threshold reduction is reported for random lasing based on a plasmonic hybrid structure of (Au core)-(SiO 2 shell) nanocubes deposited on Ag film (Au@SiO 2 NCs-Ag film). This hybrid structure could more significantly lower the lasing threshold than Ag film or Au@SiO 2 NCs. In particular, the SiO 2 shell simultaneously tuned the interactions of localized surface plasmons (LSPs) of the Au NC cores with surface plasmon polariton (SPP) of the Ag film and gain medium. The optimal thickness of the SiO 2 shell was determined that could result in the lowest lasing threshold: 14.1% that of the neat gain medium. Furthermore, compared to a hybrid structure consisting of Ag film with regular metal nanoparticles, Au@SiO 2 nanospheres, the gain medium based on a hybrid Au@SiO 2 NCs-Ag film structure had a lower lasing threshold. This was attributed to the stronger electric field enhancement and scattering of the Au NC cores than the Au nanosphere cores, ensuring marked plasmonic interaction between the SPP of the Ag film and the LSPs of the Au NC cores. Our results provide a convenient method to lower the lasing threshold of the gain medium in the presence of metal film. Image 1 • Enhanced lasing properties based on Au@SiO 2 NCs-Ag film hybrid structure is proved. • Compared to Au@SiO 2 NCs or Ag film, hybrid structure could better lower threshold. • SiO 2 shell could tune interactions of Au NC cores with Ag film and gain medium. • Threshold of device based on Au@SiO 2 NCs-Ag film is 14.1% that of neat gain medium. Compared to Au@SiO 2 NSs, Au@SiO 2 NCs with Ag film could better lower threshold. [ABSTRACT FROM AUTHOR]

Herein, three self‐assembling materials (SAMs), (pyridine‐4‐ylmethyl)phosphonic acid (PyPA), benzylphosphonic acid (BnPA), and pentafluorobenzyl phosphonic acid (F5BnPA), are selected as hole‐injecting layers in organic light‐emitting diodes (OLEDs) and the effects of the aromatic ring of SAMs on indium tin oxide (ITO) work function (WF), hole injection, and device performances are investigated. After assembling them on ITO, the X‐ray photoemission spectroscopy data suggest that three samples have a similar binding mode, and the ultraviolet photoemission spectroscopy shows the effective change of ITO WF gradually enlarged along the order of PyPA, BnPA, and F5BnPA, resulting in increase in hole‐injecting capability in turn. The calculated molecule dipole of pyridine is 2.65 Debye, clearly larger than that of phenyl (0.32 Debye) and pentafluorophenyl (1.88 Debye), but PyPA presents minimum ITO WF change. Such differentiated WF changes are not only contributed by the molecular dipole of aromatic ring but also their titling angles. In OLEDs based on tris(8‐hydroxyquinoline) aluminum (III) (Alq3), the device modified by PyPA affords the highest external quantum efficiency (EQE) of 1.45% and current efficiency (CE) of 4.62 cd A−1. However, in the device using 9‐[4‐(4,6‐diphenyl‐1,3,5‐triazine‐2‐yll)phenyl]‐N,N,N′,N′‐tetraphenyl‐9H‐carbazole‐3,6‐diamine as emitters, the OLEDs modified by F5BnPA show the best EQE of 24.85% and CE of 81.88 cd A−1. [ABSTRACT FROM AUTHOR]

We have demonstrated that the T1-state energy of a fluorescence dopant (FD) is close to that of the thermally activated delayed fluorescence (TADF)-type exciplex co-host, and the energy loss caused by the T1 states of the FD could be suppressed in TADF-sensitized fluorescence (TSF) OLEDs. To further improve device efficiency following this strategy, two compounds, TPA-FQ and dTPA-FQ, were constructed using 2-phenylfuro[2,3-b]quinoxaline (FQ) and triphenylamine (TPA) as the acceptor and donor, respectively. dTPA-FQ, with two ortho-installed TPA units, has a higher photoluminescence quantum yield (PLQY; 100%), a more rapid radiation transition of the S1 state (Kr = 1.79 × 108 s−1), and a smaller ΔES1T1 value (0.24 eV) in comparison to TPA-FQ with only one TPA unit (PLQY: 79%; Kr = 5.03 × 107 s−1; ΔES1T1 = 0.47 eV). Transient photoluminescence and absorption spectroscopy experiments revealed that both compounds are green fluorescence emitters. The dTPA-FQ shows a T1–T1 difference of only 0.05 eV from the co-host, 4,4′,4′′-tri(N-carbazolyl)triphenylamine and (1,3,5-triazine-2,4,6-triyl)-tris(benzene-3,1-diyl)-tris(diphenylphosphine oxide) (TCTA:PO-T2T), and, thus, T1 energy loss could be inhibited in the dTPA-FQ doped co-host device. As a result, an external quantum efficiency (EQE) of 10.9% has been achieved, while the device with the TPA-FQ doped co-host presents degraded device efficiency (EQE = 4.8%) due to its relatively large T1–T1 difference of 0.1 eV and lower PLQY. In the non-doped devices, the TPA-FQ device shows better device performance than the dTPA-FQ one; its luminance reaches 47 880 cd m−2 at a low voltage of 8.5 V, its EQE is up to 3.9% at 100 cd m−2, and it exhibits only 6.2% efficiency roll-off as the luminance is changed from 10 000 cd m−2 to 30 000 cd m−2. Our experiments demonstrated that the key considerations for designing a FD for a TSF system should be a high PLQY and small T1 energy difference between the FD and co-host. [ABSTRACT FROM AUTHOR]

A novel molecular scaffold, dibenzo[f,h]furo[2,3-b]quinoxaline (diBFQ), and its derivatives, 3,6-bis(4-isopropylphenyl)-11-phenyldibenzo[f,h]furo[2,3-b]quinoxaline (dP-diBFQ) and furo[2′,3′:5,6]pyrazino[2,3-f][1,10]phenanthroline (FPPhen), were designed and synthesized, showing highly efficient pure and deep blue emission. The unsubstituted molecular scaffolds diBFQ and FPPhen exhibit emission from 424–445 nm with PLQYs of ∼70%, and the disubstituted derivative of diBFQ, dP-diBFQ, shows a PLQY of 79.1%. Our experimental and theoretical investigations revealed that the additional N atoms in FPPhen facilitate the electron distribution of the HOMO orbital localizing on a smaller π-conjugate fragment compared with diBFQ, which resulted in the emission peak blue-shifting from 445 nm for diBFQ to 424 nm for FPPhen. Furthermore, introducing the steric substituent isopropylphenyl into the diBFQ scaffold would help to suppress aggregates of dP-diBFQ molecules and improve the fluorescence efficiency. OLEDs using dP-diBFQ as dopants show pure blue emission with CIE coordinates of (0.154, 0.102) and an EQE of 2.28%. Upon increasing the dopant concentration, the EQE and current efficiency could be improved to 2.63% and 4.7 cd A−1, but aggregate emission with a peak from 472–476 nm was clearly observed due to molecular aggregation. Our studies clearly suggested that diBFQ and FPPhen scaffolds are promising fluorescence cores for deep and pure-blue emission. [ABSTRACT FROM AUTHOR]

Mutation of the K-Ras gene has been widely found in non-small cell lung cancer. Compared with other mutations of lung cancer, the drugs cannot effectively target mutant K-Ras. However, the mitosis of cancer cells is vulnerable to external interference. Our previous study showed that electromagnetic fields (MFs) could suppress cell proliferation. In this article, a cell proliferation model based on the A549 cell line was established while considering the effects of MFs. In addition, the parameters of the A549 cell proliferation model were regressed by the finite difference method and verified by numerical simulation. Based on the calculations, the density of the A549 cells reflects the trend of measured data from optical microscopy. This approach not only helps reveal the mechanism of MFs on cancer cells but also suggests a new way to predict the effects of magnetic stimulation on cancer inhibition. [ABSTRACT FROM AUTHOR]

The aim of this contribution is the first numerical investigation on the electromagnetic (EM), thermal, and mechanical coupled fields of a newly developed single-stage fast linear transformer driver (FLTD) with 24-separate columns in the China Z-pinch driver CZ34. Considering the mutual influences of the EM, thermal, and mechanical fields during a pulsed current discharging process of the FLTD, the proposed numerical model is calculated using the field-circuit coupled time-domain finite integration technique (TD-FIT). By making reference to Tonti’s classification diagram, integral form state variables in the transient thermal field and mechanical field can be defined similar to those of the EM field. With appropriate time integration schemes, governing equations of different physical fields can be transformed to corresponding algebraic time-updating equations. The two-way interplays of the EM, thermal, and mechanical fields are performed with predefined coupling terms and time steps. The simulated results indicate that during one current discharging process, the temperature rise is less than 1 K and the maximum deformation generated by the Lorentz force is less than 0.1 mm. [ABSTRACT FROM AUTHOR]

Ion flow is a phenomenon that exists in the normal operation of high-voltage direct current (HVDC) transmission lines. It will increase the electric field below the wire and poses a threat to the life and health of humans. Hence ion flow is considered in the HVDC transmission line laying design as a significant factor. However, the control equation of this phenomenon is a form of convective dominance, and it is easy to cause oscillation for its solution. In this study, a mesoscopic approach, the lattice Boltzmann method (LBM), is first proposed to solve the ion flow field. Firstly, the control equation of the ion flow field is rewritten in the form of the lattice Boltzmann equation. Secondly, reducing the computation load of the model by using local mesh refinement. Then a new mesh refinement method based on distribution function is proposed and compared with several other methods. Thirdly, the analytical solutions of the coaxial cylinder model are compared with LBM results, and a measuring platform is set up also for verification. Finally, the three-layer grid is successfully applied in an 800 kV unipolar full-scale transmission line. [ABSTRACT FROM AUTHOR]

Ion flow is a phenomenon that exists in the normal operation of high‐voltage direct current (HVDC) transmission lines. It will increase the electric field below the wire and poses a threat to the life and health of humans. Hence ion flow is considered in the HVDC transmission line laying design as a significant factor. However, the control equation of this phenomenon is a form of convective dominance, and it is easy to cause oscillation for its solution. In this study, a mesoscopic approach, the lattice Boltzmann method (LBM), is first proposed to solve the ion flow field. Firstly, the control equation of the ion flow field is rewritten in the form of the lattice Boltzmann equation. Secondly, reducing the computation load of the model by using local mesh refinement. Then a new mesh refinement method based on distribution function is proposed and compared with several other methods. Thirdly, the analytical solutions of the coaxial cylinder model are compared with LBM results, and a measuring platform is set up also for verification. Finally, the three‐layer grid is successfully applied in an 800 kV unipolar full‐scale transmission line. [ABSTRACT FROM AUTHOR]

Down-conversion structure white organic light-emitting diodes (WOLEDs), in which white light is generated by a blue emission organic light-emitting diodes (OLEDs) in combination with a color conversion layer (CCL) outside the substrate, has attracted extensive interest due to its significant advantages in low cost and stabilized white-light emissions. However, low color-conversion efficiency of CCL is still a bottleneck for the performance improvement of down-conversion WOLEDs. Here, we demonstrate an approach to enhance the color-conversion efficiency of CCL-WOLEDs by localized surface plasmon resonance (LSPR) effect. In this approach, a blend of Ag nanoparticles and polyvinyl alcohol (PVA) is solution-deposited between the blue organic light emitting diodes and color-conversion layer. Based on the LSPR effect of this modified structure, the color conversion efficiency has improved 32%, from 45.4% to 60%, resulting a 14.4% enhancement of the current efficiency, from 9.73 cd/A to 11.14 cd/A. Our work provides a simple and low-cost way to enhance the performance of down-conversion WOLEDs, which highlights its potential in illumination applications. [ABSTRACT FROM AUTHOR]

A highly-efficient inverted heterojunction perovskite solar cell was prepared. A homogeneous and compact perovskite (CH3NH3PbI3) layer was prepared via a two-step solution deposition method, and subsequently a double-layer PCBM film was deposited by a sequential spin-coating/vapor deposition process as the electron transport layer. The optimised device could achieve a 12.2% (average 11.09%) efficiency. [ABSTRACT FROM AUTHOR]

As for the lasing of organic semiconductor materials, novel semi-conducting materials N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′:4′,1″-terphenyl]-4,4″-diamine (BMT-TPD) and N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′:4′,1″:4″,1′″-quaterphenyl]-4,4′″-diamine (BMQ-TPD) were synthesized. In contrast to the N,N′-diphenyl-N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TPD), the well known organic gain medium for the lasing, the two new materials have lower amplified spontaneous emission (ASE) thresholds and enhanced lasing performance. The molecular geometries in the electronic ground state and the first optically excited state as well as the vibrational modes of the three compounds have been studied by means of the dependent density functional theory (DFT). Theoretical analysis shows that, accompanying with the increased number of central phenyl rings, the uniform high-frequency modes (around at 1200, 1300 and 1650 cm − 1 ) of the three compounds are enhanced, which is driven by the C H bending and C C stretching in the central phenyl rings. Correspondingly, the enhanced vibration strength of the high-frequency modes and reinforced vibronic peak intensity bring out the distinct “four-level” energy level scheme which benefits population inversion for lasing and leads to the decreased ASE threshold. These results indicate that the synthesized materials are good candidates to act as active laser materials and our work provides an insight into the lasing of small organic molecules. [ABSTRACT FROM AUTHOR]

In this article, a typical silver-loaded anatase TiO 2 nanotube (Ag-TNTs) was developed and assembled in DSSCs. By blending the Ag-TNTs and TiO 2 nanoparticles as the composite photoanode, this hybrid nanostructure exhibits a promising architecture for accelerating electron transport as well as enhancing dye adsorption. These nanotubes could provide direct charge transfer pathways and increase electrolyte penetration in comparison with the TiO 2 nanoparticles alone network. Moreover, the presence of the Ag nanoparticles could enhance the light harvesting efficiency and promote the charge separation, which further improves the performance of the DSSCs. The DSSC with metal-modified hybrid nanostructures has achieved an efficiency of 8.19% which is about 56% higher than DSSCs based on TiO 2 nanoparticles photoanode with 5.26%. [ABSTRACT FROM AUTHOR]

A tris (8-hydroxyquinoline) aluminum (Alq3)-based organic bistable device (OBD) using Al electrode and ITO electrode modified by Ag nanoparticles (NPs) was reported. The OBD exhibits high ON/OFF switching ratios in the range of 102–103 and long retention time over 104 s. The influence of the Ag NPs densities, as well as the Alq3 film thickness on the switch performance current–voltage (I–V) of the OBDs was studied. Correlation between filament formation mechanism and charge storage mechanism was observed by analysing the I–V characteristics of OBDs with different Alq3 film thickness. As for the Alq3 film with thickness of 300 nm, the trapping effect of Ag NPs leads to both ON and OFF states for OBD; for 100 nm thick Alq3 film, the effect of filamentation dominates in the ON and OFF states of OBD. For the case of 200 nm thick Alq3 film, however, the ON state results from the filamentation effect, while trapping effect is responsible for the OFF state. In addition, the diffusion effect of Al atoms in Alq3 film in the devices was discussed and was expected to explain this thickness-dependence relationship. [ABSTRACT FROM AUTHOR]