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Large enhancement in upconverted green emission intensity from Ho3+/Yb3+ co-doped Y2Ti2O7 phosphor in the presence of Zn2+
摘要： The Ho3+, Yb3+ co-doped Y2Ti2O7 phosphor samples have been synthesized through solid state reaction method in the absence and presence of Zn2+ ions. The X-ray diffraction (XRD) analysis show that the phase of the crystal is face centered cubic. The zinc free phosphor shows weak upconversion emission in green region due to 5S2, 5F4 →5I8 transition of Ho3+ ion on excitation with 980 nm radiation. The emission intensity is enhanced significantly in the presence of Zn2+ ions due to increase in crystallinity, particle size and asymmetry in the crystal field. We are reporting ~92 times enhancement in the green emission intensity for 30 mol% co-doping of Zn2+ ions. The lifetime of 5S2 level of Ho3+ ion increases by increasing the concentration of Zn2+ ions. The intense green emission in this material may be suitable for display and other fluorescence based devices.
关键词： Upconversion,Y2Ti2O7 phosphor,Zn2+,Green emission,Ho3+ /Yb3+
更新于2025-11-14 14:48:53
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Enhanced green emission from Er-doped (AlGa) <sub/>2</sub> O <sub/>3</sub> films grown by pulsed laser deposition
摘要： Erbium (Er) doped (AlGa)2O3 films were deposited on sapphire substrates using pulsed laser deposition. The transmittance spectra and X-ray photoelectron spectroscopy measurements show that transparent (AlGa)2O3:Er films with a wider bandgap can be achieved by increasing the Al content in the targets. All films exhibit the strongest pure green emission at 550 nm with the wavelength independent of the alloy compositions. A maximum intensity observed at Al content of 0.34 is several times higher than that in Ga2O3:Er films, indicating that the intensity of green emission can be enhanced by increasing the host bandgap. Our study also reveals that too high Al content has decreased the photoluminescence intensity, which should be related to the degraded crystallinity proved by X-ray rocking curve. These results suggest that (AlGa)2O3:Er film is a promising material for fabricating efficient green luminescent devices.
关键词： photoluminescence,bandgap,green emission,pulsed laser deposition,Er-doped (AlGa)2O3
更新于2025-09-23 15:21:01
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Strategically Modulating Carriers and Excitons for Efficient and Stable Ultrapurea??Green Fluorescent OLEDs with a Sterically Hindered BODIPY Dopant
摘要： Ultrapure colors are vital for displays to obtain the highly desired wide color-gamut. Till now, only boron-dipyrromethene derivatives (BODIPYs) have demonstrated ultrapure full-colors but suffer from low excitons utilization efficiency as dopants in organic light-emitting diodes. It is proposed here that with a thermally activated delayed fluorophore to sensitize BODIPYs, all excitons can be recycled, which, still, is challenged by exciton loss through Dexter energy transfer (DET) from sensitizer to dopant and direct charge trapping on BODIPYs. Hence, a sterically hindered BODIPY-type dopant with a bulk substituent on the meso-position is developed to suppress DET, exhibiting a high photo-luminance quantum yield of 98% and a small full width at half maximum of 28 nm. Moreover, the device structure is elaborately designed, successfully modulating carriers and excitons to avoid charge trapping on dopant and also trigger multiple-sensitizing processes to reduce exciton loss. Consequently, a state-of-the-art maximum external quantum efficiency/power efficiency of 19.0%/85.7 lm W?1 are realized together with an ultrapure-green emission of Commission Internationale de l’Eclairage coordinates of (0.26, 0.67) and a long half-lifetime of 2947 h at an initial luminance of 1000 cd m?2.
关键词： carrier modulation,ultrapure green emission,exciton modulation,high-efficiency devices,fluorescent organic light-emitting diodes,long-lifetime devices
更新于2025-09-23 15:21:01
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Tunable luminescence and transmittance nature of CdS:PMMA nanocomposites for optoelectronic applications
摘要： Optical and energy storage materials based on semiconductors are of great interest today. The present report explains the semiconductor nanocomposite centered on highly transparent Poly(methyl methacrylate) (PMMA) matrix and Cadmium Sulphide (CdS) nano particles. The solid ?lms of CdS:PMMA composite was prepared using simple and cost e?ective solution casting technique. The surface morphology and the presence of CdS particles in PMMA matrix was analysed using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray spectra (EDX). The size of the particles was analysed using Atomic Force Microscopy (AFM) and Transmission Electron Microscope (TEM) and they revealed the presence of nano sized particles. The narrow size distribution of particles was identi?ed from TEM and AFM analysis. The transmittance of the CdS:PMMA nanocomposite solid ?lms was found to be above 90%. The blue and green emission of CdS:PMMA nanocomposite solid ?lms were observed from Photoluminescence (PL) spectra.
关键词： Composite materials,Polymeric composite,Luminescence,Green emission,Particle distribution,Transmittance
更新于2025-09-23 15:21:01
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High-purity green emission in Yb3+/Ho3+ Co-doped BaIn6Y2O13 up-conversion phosphor
摘要： Yb3+-Ho3+ pairs doped BaIn6Y2O13 (BIY) phosphors were successfully prepared through sol-gel process, and the crystal structure and optical properties were investigated in detail. As-prepared samples exhibited strong green and weak red emission peaked at 549 nm and 652 nm originated from Ho3+ transitions of 5S2, 5F4 → 5I8 and 5F5 → 5I8 with 980 nm excitation, respectively. The dopant contents, pumping power and pulse width of excitation laser dependent up-conversion luminescence (UCL) spectra of samples were modulated to acquire the intense and high-purity green emissions. Moreover, possible dynamic UCL process from non-steady-state to steady-state between Yb3+ and Ho3+ was schematically proposed in detail. These results indicate that BaIn6Y2O13: Yb3+/Ho3+ phosphors with strong and pure green UC emissions are potential candidates in display and lighting technology.
关键词： Up-conversion,Phosphor,Green emission,Non-steady-state
更新于2025-09-19 17:15:36
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Room-temperature continuous-wave operation of green vertical-cavity surface-emitting lasers with a curved mirror fabricated on {20a??21} semi-polar GaN
摘要： We demonstrate a room-temperature continuous-wave operation of green vertical-cavity surface-emitting laser with a 20-μm-long cavity possessing a dielectric curved mirror formed over a {20?21} semi-polar Gallium Nitride substrate. The emission wavelength and the threshold current were 515 nm and 1.8 mA, respectively. We also confirmed that white light is generated by overlaying three prime colors of light, i.e. red, blue and green, emitted only from vertical-cavity surface-emitting lasers.
关键词： curved mirror,green emission,continuous-wave operation,semi-polar GaN,vertical-cavity surface-emitting laser
更新于2025-09-19 17:13:59
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Highly Efficient Cyan-Green Emission in Self-Activated Rb <sub/>3</sub> RV <sub/>2</sub> O <sub/>8</sub> (R = Y, Lu) Vanadate Phosphors for Full-Spectrum White Light-Emitting Diodes (LEDs)
摘要： Phosphor-converted white-light-emitting diodes (pc-WLEDs) rely on combining a near-ultraviolet (n-UV) or blue chip with trichromatic and yellow-emitting phosphors. It is challenging to discover cyan-green-emitting (480?520 nm) phosphors for compensating the spectral gap and producing full-spectrum white light. In this work, we successfully discovered two unprecedented bright cyan-green emitting Rb3RV2O8 (R = Y, Lu) phosphors that gives emission bands centered at 500 nm upon 362 nm n-UV light excitation. Interestingly, the both self-activated compounds exhibit high internal quantum e?ciencies (IQEs) of 71% for Rb3YV2O8 and 85% for Rb3LuV2O8, respectively. Moreover, controllable emission color can be successfully tuned from cyan-green to orange-red across the warm white light region by design strategy of VO4 3? → Eu3+ energy transfer. The thermal quenching of as-prepared phosphors could be e?ectively mitigated by this design strategy. Finally, the as-fabricated n-UV (λ ex = 370 nm) pumped phosphor-converted (pc) W-LED devices utilizing Rb3RV2O8 (R = Y, Lu) along with commercial phosphors demonstrate well-distributed warm white light with high color-rendering index (CRI) of 91.9 and 93.5, and a low correlated color temperature (CCT) of 5095 and 4946 K. It suggests that the both vanadate phosphors have potential applications in full-spectrum pc-WLEDs.
关键词： cyan-green emission,self-activated,full-spectrum white light-emitting diodes,energy transfer,vanadate phosphors
更新于2025-09-19 17:13:59
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Luminescent properties of CaSc2O4:Ce3+ green phosphor for white LED and its optical simulation
摘要： Green-emissive Ce3t-doped CaSc2O4 phosphors were synthesized by solid-state method. The water washing process of the as-prepared samples was several times conducted because of severe hydration of unreacted CaO and CaF2 flux residual. The washed CaSc2O4:Ce3t phosphors showed a single phase with a crystallite size of 1–3 μm, and its photoluminescence intensity was 10% improved compared with the as-prepared. It shows the broad 450 nm excitation peak and the green emission peak at 520 nm with a half width of 105 nm. Its temperature dependence showed the similar thermal stability with a commercial silicate phosphor. The optical simulation and the real fabrication of white LEDs with a combination of our green phosphor and one of possible orange-red phosphors demonstrated that the white LED with Sr3SiO5:Eu2t orange phosphor gives the best luminous efficacy and the appropriate color rendering index of 70 under the daylight color temperature of 6400 K.
关键词： CaSc2O4:Ce3t,White-light-emitting diode,Optical simulation,Photoluminescence,Green emission
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Third Harmonic Generation in Highly-Doped Silica Glass Micro Ring Resonator
摘要： The paper discusses the green emission generation in a highly doped silicon ring resonator with core input power. It explores the first observation of green emission by third-harmonic generation in a silicon ring resonator, highlighting the potential for integrated photonic applications.
关键词： green emission,silicon ring resonator,integrated photonics,third-harmonic generation
更新于2025-09-12 10:27:22
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Vapor-Phase Growth of CsPbBr <sub/>3</sub> Microstructures for Highly Efficient Pure Green Light Emission
摘要： All-inorganic lead halide perovskites have been extensively studied in the past several years due to their superior stability against moisture, oxygen, light, and heat compared with their organic–inorganic counterparts. CsPbBr3 with suitable band gap and ultrahigh photoluminescence quantum yield is a promising candidate for pure green emitter in the backlighting display to fill the so-called “green gap.” Here, vapor-phase growth of CsPbBr3 microspheres is reported for highly efficient pure green light emission. The as-synthesized microspheres exhibit a stronger photoluminescence (PL) intensity with a photoluminescence quantum yield of 75% resulting from the lower energy of longitudinal optical phonons revealed by temperature dependent PL studies. Importantly, with the diameter increasing from 2 to 50 μm the PL peak positions of the microspheres can be readily tuned from 527 to 539 nm, well filling the so-called “green gap.” The red-shift with increasing diameter can be ascribed to the reabsorption process during the photon propagation inside the microspheres. The studies provide a route to improve the photoluminescence quantum yield in all-inorganic lead halide perovskites, but also suggest an alternative approach to achieve the pure green emission for the backlighting display.
关键词： LO phonon,CsPbBr3,microspheres,reabsorption,pure green emission
更新于2025-09-10 09:29:36