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- 摘要
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- 实验方案
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Towards white light emission from a hybrid thin film of a self-assembled ternary samarium( <scp>iii</scp> ) complex
摘要： A new samarium complex [Sm(hfaa)3(Py-Im)] (ML) was synthesized by utilizing hexafluoroacetylacetone (hfaa) and 2-(2-pyridyl)benzimidazole (Py-Im) as coordinating ligands. A single crystal X-ray analysis shows that in the solid-state the complex dimerizes through intermolecular hydrogen-bonding with N–H···O (2.127 ?) and N–H···F (2.576 ?) interactions. The complex in the solid-state displayed highly monochromatic brilliant red emission with Commission International de I’Eclairage (CIE) color coordinates of 0.6532; 0.3336, with a remarkably long luminescence lifetime (≈ 204.47 ± 4.043 μs) and a high intrinsic quantum yield (≈ 6.60 %). Furthermore, the complex in different organic media displayed color tunability from orange (CIE; 0.6071; 0.3568) to violet (CIE; 0.3634; 0.2144) with from 105.50 ± 0.143 – 14.27 ± 0.033 μs. Hybrid and flexible thin films obtained by doping different concentrations (1%, 2%, 4% and 6%) of the complex into the poly(urethane) (PU) polymer matrix also exhibited color tunability from violet (CIE; 0.3380; 0.2162) to light orange (CIE; 0.5666; 0.3408). White light emission from a 1% doped thin film of the complex was realized by changing the excitation wavelength. The new material could be a potential candidate for the fabrication of full-color display devices and for solid-state lighting (SSL) applications.
关键词： luminescence,white light emission,color tunability,samarium complex,solid-state lighting
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Optimizing Device Characteristics for VLS-Grown InP Heterojunction Solar Cells
摘要： This paper presents the implementation of an automated roll-to-roll ?uidic self-assembly system based on the surface tension driven self-assembly with applications in the ?eld of macroelectronics. The reported system incorporates automated agitation, web motion, component dispensing, and recycling. The process enables the assembly and electrical connection of semiconductor dies/chips in a continuous and parallel method achieves an assembly rate of 15 000 chips per hour and an assembly yield exceeding 99%, testing assembly of standard square-shaped dies, 300–1000 μm size. Scaling the system to any desired throughput is possible due to the parallel manner of self-assembly. The identi?cation and the modeling of the relationship between process parameters and forces have been studied and experimentally veri?ed by testing the effect of the web angle, agitation on assembly, and detachment rates. As an application, we demonstrate the realization of a solid-state lighting module. This particular application requires the assembly of a conductive multilayer sandwich structure, which is achieved by combining the introduced assembly process with a novel lamination step.
关键词： Roll-to-roll,flexible electronics,fluidic self-assembly,solid state lighting
更新于2025-09-19 17:13:59
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Investigations on RE(TTA)3tppo (RE=Eu/Sm/Eu0.5 Sm0.5) rare earth β-diketonate complexes for OLEDs and solid state lighting
摘要： Rare earth hybrid organic β-diketonate complexes of Eu(III), TTA and tppo; Eu(TTA)3tppo, Sm(TTA)3tppo and Eu0.5Sm0.5(TTA)3tppo [Eu: europium, Sm: samarium, TTA: Thenoyl Trifluoro Acetone, tppo: Triphenylphosphine oxide] were synthesized by solution technique, maintaining pH 7. X-ray diffractogram of all the complexes revealed their crystalline nature. TGA curves infer their thermal stability to be in the range of 2300C - 2600C. The optical energy band gap of these complexes was found to be in the range of 3.08 to 3.20 eV. When RE(TTA)3tppo complexes were excited at 377 nm, 382 nm and 382 nm respectively, the emission spectra portrays red emission, peaking at 616 nm, 645 nm and 616 nm in solid state, while in solvated state, hypsochromic shift (shift toward lower wavelength) was noticed. CIE co-ordinates and color correlated temperature (CCT) of the complexes tuned according to their emission wavelength. These investigations provide a good deal of information regarding their suitability for the fabrication of red to blue tunable light emitting organic light emitting diodes (OLEDs), panel displays and solid state lighting panels on flexible substrates.
关键词： Samarium,flat panel displays,Rare earth β-diketonates,europium,OLED devices,solid state lighting
更新于2025-09-16 10:30:52
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[IEEE 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Daejeon, Korea (South) (2019.7.28-2019.8.1)] 2019 International Conference on Optical MEMS and Nanophotonics (OMN) - Ultra-Broadband and Polarization-Insensitive Tunable Metasurface Absorber
摘要： This paper presents the implementation of an automated roll-to-roll ?uidic self-assembly system based on the surface tension driven self-assembly with applications in the ?eld of macroelectronics. The reported system incorporates automated agitation, web motion, component dispensing, and recycling. The process enables the assembly and electrical connection of semiconductor dies/chips in a continuous and parallel method achieves an assembly rate of 15 000 chips per hour and an assembly yield exceeding 99%, testing assembly of standard square-shaped dies, 300–1000 μm size. Scaling the system to any desired throughput is possible due to the parallel manner of self-assembly. The identi?cation and the modeling of the relationship between process parameters and forces have been studied and experimentally veri?ed by testing the effect of the web angle, agitation on assembly, and detachment rates. As an application, we demonstrate the realization of a solid-state lighting module. This particular application requires the assembly of a conductive multilayer sandwich structure, which is achieved by combining the introduced assembly process with a novel lamination step.
关键词： solid state lighting,Roll-to-roll,fluidic self-assembly,flexible electronics
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE Industry Applications Society Annual Meeting - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Industry Applications Society Annual Meeting - Evaluation of Bit Error Ratio in Differential Phase-Shift-Keying Modulation Applied to VLC LED Drivers
摘要： This work presents a binary differential phase-shift keying (DPSK) modulation technique for visible light communication (VLC) systems aimed at low to moderate data rate applications. VLC uses the modulated light of LEDs to transmit data wireless. Such feature is added into artificial lighting systems by controlling the light intensity of a source. However, in most cases, modulation capabilities for VLC are employed with the addition of extra power components, which may harm efficiency and cost standards. Therefore, single switch LED drivers are preferable to provide VLC along with average current regulation. They are standard low-cost solutions that are able to perform both functions providing a satisfactory efficiency. Hence, in this work, DPSK modulation is applied to a buck converter operating in continuous conduction mode at 250 kHz, providing a raw data rate of 125 kbps. DPSK is advantageous because it overcomes possible parameters changes at the converter, along with possible duty cycle changes given by the control system of the average current for lighting. Moreover, the system performance is evaluated by means of its bit error ratio (BER) over signal-to-noise ratio (SNR), in a line-of-sight setup with variable distances between transmitter and receiver, showing a good behaviour of a BER less than 10?3 for about 8.1 m in a 8.4 W LED load.
关键词： Switched Converter,Solid-State Lighting,Light Emitting Diode,Visible Light Communication
更新于2025-09-12 10:27:22
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Transition metal ion Co-Doped MgO–MgF2-GeO2:Mn4+ red phosphors for white LEDs with wider color reproduction gamut
摘要： Mn4+-activated non-rare-earth based red phosphors are excellent down conversion materials for phosphor-converted light-emitting diode (pc-LEDs) based solid-state lighting applications. However, the low quantum efficiency of Mn4+ activated red phosphors under InGaN based blue LED excitation hinders their use in phosphor-converted LEDs. To enhance the absorption at an excitation wavelength of around 420 nm in Mn4+-doped MgO-MgF2-GeO2 (MGF: Mn4+), which is a conventional red-emitting lamp phosphor, we doped MGF: Mn4+ phosphors with transition metal oxides (Sc2O3, Lu2O3, Y2O3, and La2O3) replacing MgO. When excited using 420 nm light, the absorption ratio of the synthesized phosphors with Sc2O3 (Sc-MGF:Mn4+) was 58% with an internal quantum efficiency (IQE) of 55% as compared to the 35% IQE of the pristine MGF-Mn4+ phosphor. White LEDs were fabricated using Sc-MGF-Mn4+ (red), and β-SiAlON:Eu2+ (green) on InGaN chips (λem = 450 nm) and their performance was compared to the optical performance of LEDs fabricated using K2SiF6:Mn4+ as the red phosphor. According to the National Television System Committee (NTSC) standard, the color reproduction coverage with an Sc-MGF:Mn4+ phosphor-loaded white LED was 121% by the International Commission on Illumination (CIE) 1976, and 80% by the BT.2020 standard. The coverages are 9% and 6% higher than the coverages of LEDs fabricated using K2SiF6:Mn4+ as the red phosphor according to the NTSC and BT.2020 standards, respectively. Our simple approach to enhance the IQE of Mn4+ activated phosphors by co-doping transition metal oxides can be extended to other Mn4+ activated phosphor systems for applications that require enhanced absorption, higher luminescent emission intensity, and a wider gamut of color reproduction.
关键词： MgO-MgF2-GeO2,Mn4+ activated red phosphors,Solid-state lighting,White LEDs,BT.2020
更新于2025-09-12 10:27:22
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Fundamentals and Applications of Red Light-Emitting Diodes (LEDs) <i>In Vitro</i> Plant Growth on Tomato <i>Lycopersicon esculentum Mill</i>
摘要： The aim of these studies was mainly to investigate the effects of monochromatic LEDs applied singly on the in vitro plant growth and morphogenesis. Various morphological and physiological parameters are considered that influence the growth and development of plants in vitro under red LED light as compared to those under normal light. Upon exposure to LED, in vitro-raised plants have shown significant improvements in growth and morphogenesis. In particular, red and blue lights, either alone or in combination, have a significant influence on plant growth. The present study gives an overview of the fundamentals of LEDs and describes their effects on in vitro plant growth and morphogenesis and their future potentials. The main objective of this study was to carry out line and combing ability of plant growth on tomato.
关键词： Solid-state lighting,Light-emitting diode,In vitro morphogenesis,Spectral quality
更新于2025-09-11 14:15:04
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Optimization and performance of nitrogen-doped carbon dots as a color conversion layer for white-LED applications
摘要： In this study, green-emitting nitrogen-doped carbon dots (N-CDots) were synthesized and incorporated into drop-cast composite films for use as color conversion layers in a white-LED configuration to generate white light. In order to resolve the red deficiency of this configuration, a commercial red phosphor was integrated into the system. Moreover, the N-CDots were also processed into polymer/N-CDot composite fibers, for which we determined the amount of N-CDots that yielded adequate white-light properties. Finally, we showed that white light with excellent properties could be generated by employing both of the fabricated N-CDot composites either as drop-cast films or composite fibers. Hence, N-CDots provide a promising alternative to inorganic phosphors that are commonly employed in white-LED configurations.
关键词： PVP,nitrogen-doped carbon dots,color conversion layer,electrospinning,white-light generation,white LED,solid-state lighting
更新于2025-09-11 14:15:04
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Applied Nanophotonics || Lighting with nanostructures
摘要： This chapter considers application of various nanostructures in lighting devices and components. It includes an introduction to photometry and color perception by humans, and discussion of colloidal quantum dots as spectral converters in display devices and lighting sources; advances in development of colloidal quantum dot light-emitting diodes (LEDs); epitaxial quantum well structures as the core technology in solid-state lighting; the potential for metal nanostructures to improve efficiency of light sources; and the outlook for challenging issues in this field. The new trends in eye-friendly customized lighting and the lighting adapted to human biorhythms are covered, and possible application of residential lighting systems for wireless optical communication (Li-Fi) are discussed.
关键词： colloidal quantum dots,metal nanostructures,nanostructures,LEDs,Li-Fi,solid-state lighting,lighting devices
更新于2025-09-09 09:28:46
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Optical investigation of Er3+ and Er3+/Yb3+ doped zinc-tellurite glass for solid-state lighting and optical thermometry
摘要： Er3+ and Er3+/Yb3+ doped zinc tellurite (ZnO/TeO2) glasses were prepared using melt quenching technique. Spectroscopic properties of the glasses were studied by absorption spectroscopy, luminescence spectroscopy, and color chromaticity coordinates (CIE-1931) measurements. Upconverted-emission intensities and the CIE-1931 coordinates were strongly affected by the presence of Yb3+ ion, as well as the excitation power density of 975 nm laser light. Effect of temperature on green upconverted-emissions from two thermally coupled 2H11/2 and 4S3/2 levels of Er3+ ions were measured and fluorescence intensity ratio technique was applied to investigate the temperature sensing properties. High sensitivity and short response time properties make ZnO/TeO2 glasses a very good candidate for non-contact optical temperature sensor applications. The maximum sensitivity of the glasses doped with Er3+ and Er3+/Yb3+ were found to be 72×10-4 K-1 and 120×10-4 K-1 at 429 K, respectively which are much higher than previously reported temperature sensors based on Er3+ ion doped materials. Hence, Er3+/Yb3+ doped zinc-tellurite glass can be more suitable than that of doped with Er3+ ions only for color tunable solid-state lighting and non-contact optical thermometry applications.
关键词： Solid-state lighting,non-contact optical thermometry,fluorescence intensity ratio (FIR),zinc-tellurite glass,upconversion
更新于2025-09-09 09:28:46