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Thermodynamic stability, half-metallic and optical nature of graphene-like Mn <sub/>2</sub> Zr <i>Z</i> ( <i>Z</i> = Ge, Si): <i>Ab initio</i> study
摘要： Half-metallic, optical and thermodynamic phase diagrams of two-dimensional Mn2ZrZ (Z = Ge, Si) have been calculated by density functional theory (DFT) framework with full-potential linear augmented plane-wave (FP-LAPW) method. The spin-polarized electronic computations show that these layers have metallic behavior with a spin polarization less than 100%. It is observed that with increasing thickness of the layers, both the thermodynamic and energy stabilities increased, and the graphene-like layers of Mn2ZrGe with a thickness of 7.6955 ?A and Mn2ZrSi with a thickness of 7.551 ?A are completely stable thermodynamically. The optical responses of Mn2ZrZ (Z = Ge, Si) have anisotropy at infrared region versus the optical direction and have high metallic nature in this optical range. The plasmonic frequencies have occurred after the visible edge and the refraction index becomes lower than one after the ultra-violet edge.
关键词： optical property,half-metal,thermodynamic phase diagram,DFT,Graphene-like Mn2ZrZ (Z = Ge, Si)
更新于2025-09-23 15:21:21
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Temperature and hydrostatic pressure effects on the electronic structure, optical properties of spherical segment quantum dot/wetting layer and group velocity of light
摘要： To investigate hydrostatic pressure and temperature effects on electron energy levels of an InAs spherical segment quantum dot with wetting layer embedded in GaAs barrier, we use the finite element method to solve the Schr?dinger equation in the effective mass approximation. Results show that the ground, the first and the second excited state energies decrease (increase) as the hydrostatic pressure (temperature) increases for the constant temperature (pressure). Moreover, given the optical properties of the system interacting with two laser fields, red (blue) shifts are observed in the linear and nonlinear absorptions and dispersions for the probe pulse as the hydrostatic pressure (temperature) increases. Furthermore, as the hydrostatic pressure increases, the maximum of the group velocity of light inside the slow light frequency range increases and the slow light frequency range shifts to the lower probe frequencies.
关键词： temperature,group velocity of light,hydrostatic pressure,optical property,quantum dot/wetting layer
更新于2025-09-23 15:21:01
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Wet Chemical Synthesis of Entangled Nano-fibrous Conducting Polyaniline (PANI) Mesh: Effect of Heating and Stirring
摘要： An effect of heating and stirring in a facile wet chemical route to synthesize entangled nano-fibrous mesh of doped polyaniline (PANI) was reported. The structural, morphological, and optical properties of PANI nano-fibers were found to be dependent on synthesis temperature and stirring. The XRD analysis confirms nano PANI formation with 2θ peaks around 15°, 21°, and 25° for (011), (020), and (200) crystal planes, respectively. The average crystallite size varies between 25 nm to 60 nm due to change in synthesis conditions. The SEM analysis reveals the clustered granule formation for PANI sample synthesized at 28 and 60 ℃ under continuous stirring, whereas, unstirred synthesis at 60 ℃ shows entangled nano-fibrous mesh morphology. The TGA study shows better thermal stability for PANI mesh over granular PANI. The FTIR spectra validates the emeraldine salt PANI formation with peaks corresponding to C-H, C-N, N=Q=N, N=B=N, and N-H vibration bands. The UV-Vis analysis shows the major absorbance peaks around λ: 340 nm (π- π* transition of benzenoid ring), and λ: 800 nm (π- π*, polaron-π* transitions). The dense entangled nano-fibrous coating of PANI synthesized at 60 ℃ without stirring shows highest electrical conductivity of 3.79 S·cm-1.
关键词： polyaniline,optical property,nano-fibrous mesh,electrical conductivity
更新于2025-09-23 15:19:57
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Effects of external magnetic field on the micro-structure of diamond-like carbon film prepared by pulsed laser deposition
摘要： The DLC ?lm was deposited by pulsed laser deposition in an external magnetic ?eld, and its optical property, surface morphology and atomic bonds were researched. The simulated ?ight tracks of the carbon ions in the magnetic ?eld showed that a number of the carbon ions were constrained by the Lorentz force, ?ing onto the substrate and forming the DLC ?lm. The contrast between the micro-structures of the DLC ?lms deposited in or out the magnetic ?eld showed that the external magnetic ?eld changed the expansion of the laser-produced plume and con?ned the surface diffusion of the charged particles on the substrate, improving the content of the sp3 bonds in the DLC ?lm.
关键词： pulsed laser deposition,diamond-like carbon ?lm,external magnetic ?eld,optical property,atomic bond
更新于2025-09-23 15:19:57
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First-principles study on photovoltaic properties of 2D Cs <sub/>2</sub> PbI <sub/>4</sub> -black phosphorus heterojunctions
摘要： Both 2D perovskite Cs2PbI4 and phosphorus are significant optoelectronic semiconductor materials, the optical-electrical characters between both contact interfaces are interesting topics. In present work, we demonstrate comparative investigation of optoelectronic properties for two kinds of electrical contact interfaces. i.e. Pb–I and Cs–I interfaces with black phosphorus contacts. The carrier transport, charge transferring and optical properties for both cases are investigated by using first principle calculation. Both contact interfaces exhibit type II band alignment with direct band gap. Charge carrier migration from Cs–I interface to black phosphorus is more strong than that of Pb–I interface by considering differential charge density and bader charge between distinct electrical contact interfaces. Besides, electron–hole effective masses of heterojunctions for both cases along different direction are investigated. Optical absorption coefficients of both cases are compared with those of free-standing Cs2PbI4 and black phosphorus in the visible spectrum. We systematically compared advantages and disadvantages of two kinds of contact interfaces for photovoltaic application, and the results reveal interfacial engineering of 2D heterojunction plays a important role in tuning optoelectronic properties.
关键词： optical property,first-principles,electronic structures,2D heterojunction,carrier effective masses,charge transfer
更新于2025-09-23 15:19:57
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CuInS <sub/>2</sub> -Doped ZnS Quantum Dots Obtained via Non-Injection Cation Exchange Show Reduced but Heterogeneous Blinking and Provide Insights into Their Structurea??Optical Property Relationships
摘要： Cadmium-free CuInS2-doped ZnS quantum dots (QDs) are synthesized through a 2-step non-injection synthetic method. The resulting QDs are small (8 nm or less) and relatively isotropic with photoluminescence quantum yields (PL QY) up to almost 70% and emission peaks in the 560-600 nm window, depending on the amount of Zn precursor added. The results indicate small CuInS2 ‘clusters’ within a zinc-blende ZnS lattice are the radiative recombination centers in the nanoparticle. Interestingly, higher ensemble photoluminescence quantum yields (PL QY) result when cation exchange is less extensive (~80 % ZnS composition), while a reduction in blinking is observed when ZnS composition exceeds 99%. A wide heterogeneity in blinking behavior from QD-to-QD is evident and a subpopulation statistical analysis shows that the on-state dwell times change from multiexponential (or inverse power law) behavior towards more mono-exponential behavior for particles that spend more of their time in the on-state. These results indicate that, as the number of CuInS2 emitting centers is reduced, the number of pathways leading to the off-state decreases, and a model is proposed to relate this behavior to the QD structure. These results provide a novel route towards CuInS2-doped visible-light emitting ZnS QDs with high quantum yield and reduced blinking and provides insight into how the composition of dopant and host matrix affects the radiative recombination mechanisms in single particles.
关键词： non-injection cation exchange,CuInS2-doped ZnS,blinking,structure-optical property relationships,quantum dots
更新于2025-09-23 15:19:57
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Recent development of soluble hole injection material for OLED display
摘要： We developed soluble hole injection materials and inks, named ELsource, that can be used as hole injection layer in organic light-emitting diode (OLED) display. OLED is an optical device. Therefore, we developed the hole injection materials with optical properties necessary for an optical device.
关键词： refractive index,optical property,printable OLED,flexible,HIL,hole injection layer,soluble,hole injection material,adhesion,HIM
更新于2025-09-23 15:19:57
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Nonlinear optical and optical power limiting studies of Zn1-xMnxO thin films prepared by spray pyrolysis
摘要： Zn1-xMnxO (x=0, 0.02, 0.04, 0.06, 0.08 and 0.1) thin films were deposited at 723 K temperature on glass substrate using a solution of molarity of 0.0125M through spray pyrolysis method. X-ray diffractogram (XRD) analysis confirmed that all the films have (0 0 2) as a preferential orientation with hexagonal wurtzite structure. The increase of dopant marginally changed the crystallite size and lattice parameters. Surface morphology changes fibrous to spherical structure with an increase in doping. X-ray photoelectron spectroscope (XPS) measurements proved the occurrence of manganese is in the Mn2+ transition state along with Oxygen and Zinc content. The films showed ~90-80% transmittance in the visible region with increasing in Mn concentration. The energy band-gap reduced with increase in dopant, due to sp-d exchange interactions. The nonlinear optical (NLO) properties were studied using z-scan technique under continuous wave (CW) diode pumped solid-state (DPSS) laser operating at 532 nm wavelength. Reverse saturable absorption (RSA) behaviors observed in both undoped and Mn doped films which is attributed to two-photon absorption (TPA) process. The optical limiting properties were also studied, which suggests that the prepared thin films could be used as optical limiters in the visible region.
关键词： ZnMnO films,structural property,nonlinear optical properties,optical property
更新于2025-09-19 17:15:36
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Polarization dependence of optical properties of single-mode polymer optical waveguides fabricated under different processes at 1310/1550 nm
摘要： We experimentally investigate the polarization dependence of the optical properties of single-mode polymer optical waveguides. We compare two types of waveguides composed of the same polymer materials: step-index square-core waveguides fabricated using the direct curing method and graded-index (GI) circular-core waveguides fabricated using the Mosquito method. We demonstrate that the GI circular-core single-mode waveguides exhibit remarkably small dependence of optical loss on the polarization angle, which is less than 0.1-dB polarization dependent loss (PDL) at both 1310 and 1550 nm wavelengths. This steady polarization property is attributed to the material stress free to the composing polymers during the fabrication process of the Mosquito method and to parabolic GI profile formed in symmetric circular core.
关键词： single-mode polymer optical waveguides,optical interconnections,step-index,the Mosquito method,polarization dependent optical property,graded-index,direct curing method
更新于2025-09-19 17:13:59
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Simulation analysis of the optical properties of a liquid crystal-filled microstructured optical fiber
摘要： The optical properties of a liquid crystal-?lled microstructured optical ?ber (LC-MOF) were investigated using the ?nite element method. Liquid crystal E7 was designed to be in?ltrated into six small air holes at the neighbourhood of silica core. Simulation results showed that the designed LC-MOF supported a continuous transmission in the silica core over a wide wavelength range. The optical properties of core modes such as refractive index, birefringence, con?nement loss, model area, group refractive index, group birefringence, and zero dispersion wavelength, were illustrated. The structure parameters of LC-MOF and temperature could be used to adjusted the optical properties. The designed LC-MOF, providing a way for ?lling high refractive index materials in MOF air holes, has potential applications in optical ?ber modulators and sensors.
关键词： optical property,liquid crystal,microstructured optical ?ber
更新于2025-09-19 17:13:59