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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) - Inserting a Low-Refractive-Index Dielectric Rear Reflector into PERC Cells: Challenges and Opportunities
摘要： Light emitting devices based on Si quantum dots/SiO2 multilayers with dot size of 2.5 nm have been prepared. Bright white light emission is achieved under the dc driving conditions and the turn-on voltage of the device is as low as 5 V. The frequency-dependent electroluminescence intensity was observed under ac conditions of square and sinusoidal wave. It was found that the emission wavelength changes with frequency when sinusoidal ac is applied. The degradation of emission intensity is less than 12% after 3 h for ac driving condition, exhibiting the better device stability compared to the dc driving one.
关键词： electroluminescence (EL),Direct current (dc),Si quantum dots (Si QDs),frequency dependent
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Evaluation of Unauthorization at the Express-Control of Heating of Natural Gas
摘要： Light emitting devices based on Si quantum dots/SiO2 multilayers with dot size of 2.5 nm have been prepared. Bright white light emission is achieved under the dc driving conditions and the turn-on voltage of the device is as low as 5 V. The frequency-dependent electroluminescence intensity was observed under ac conditions of square and sinusoidal wave. It was found that the emission wavelength changes with frequency when sinusoidal ac is applied. The degradation of emission intensity is less than 12% after 3 h for ac driving condition, exhibiting the better device stability compared to the dc driving one.
关键词： electroluminescence (EL),Direct current (dc),Si quantum dots (Si QDs),frequency dependent
更新于2025-09-23 15:21:01
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Mechanism of leakage current increase in p-GaN gate AlGaN/GaN power devices induced by ON-state gate bias
摘要： An increase in OFF-state leakage current in p-GaN gate AlGaN/GaN high-electron-mobility transistors (HEMTs), induced by ON-state gate bias, was observed and reported in this paper. Higher OFF-state leakage current was observed with higher gate bias voltage and longer bias duration. We propose that the initial increase in OFF-state leakage current and its subsequent decay with time are due to persistent photoconductivity effects in GaN induced by hole injection and electroluminescence during the ON-state gate bias. At room temperature, it took more than 20 s for the increased leakage current to reduce to its equilibrium level in the dark. The related physical mechanisms underlying this phenomenon in the p-GaN gate HEMT structure are also proposed.
关键词： p-GaN gate,AlGaN/GaN HEMTs,persistent photoconductivity,leakage current,electroluminescence
更新于2025-09-23 15:21:01
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Graphene for Flexible Lighting and Displays || Graphene-based quantum dot emitters for light-emitting diodes
摘要： Quantum dot is a zero-dimensional material that is introduced from the quantum con?nement effect when it is sized in nanometer scale and has various electrical and optical properties depending on the size of the particle. The electrons con?ned in small areas of nanoscale which are smaller than exciton Bohr radius are quantized and limited in free motion, and electrons in quantum dot are con?ned in every three direction by the quantum con?nement effect which causes a ?nite number of electron, hole, and exciton states, resulting in various characteristics on the size of the particle. In other words, the full con?nement in every three direction results in the complete quantization or discretization of the energy states of con?ned charge carriers in quantum dot [1]. Therefore, the fewer energy levels are quanti?ed as the energy level of the carrier decreases as the particle size decreases, resulting in a wider and more discretized bandgap [2e4].
关键词： electroluminescence,light-emitting diodes,quantum confinement,graphene quantum dots,photoluminescence
更新于2025-09-23 15:21:01
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LED Structures Based on ZnO Films Obtained by RF Magnetron Sputtering for the UV Spectral Range
摘要： Data for the influence of different defects on the photoluminescence and electroluminescence spectra (emission intensity and wavelength) of n-ZnO/p-GaN structures are reported.
关键词： ZnO films,photoluminescence,RF magnetron sputtering,UV spectral range,electroluminescence
更新于2025-09-23 15:21:01
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Red-Emitting Thermally Activated Delayed Fluorescence Polymers with Poly(fluorene- <i>co</i> -3,3′-dimethyl diphenyl ether) as the Backbone
摘要： A series of red-emitting thermally activated delayed ?uorescence (TADF) polymers have been designed and synthesized based on poly(?uorene-co-3,3′-dimethyl diphenyl ether) (PFDMPE) as the backbone. Compared with poly?uorene (PF, 2.16 eV), the introduction of 3,3′-dimethyl diphenyl ether into the main chain of PFDMPE leads to the increased triplet energy of 2.58 eV, which is higher enough than the tethered red TADF guest (2.13 eV) to prevent the unwanted triplet energy back-transfer. Meanwhile, there is a good overlap between the absorption spectrum of the red guest and the photoluminescence (PL) spectrum of the polymeric host, ensuring the e?cient energy transfer from host to guest. Consequently, the resultant polymers PFDMPE-R01 to PFDMPE-R10 in solid states show obvious red TADF properties with delayed ?uorescence lifetimes of 126?191 μs and PL quantum yields of 0.18?0.55. Among them, PFDMPE-R05 obtains the best device performance, revealing a bright red electroluminescence peaked at 606 nm and a promising current e?ciency of 10.3 cd/A (EQE = 5.6%). The results compete well with those of red phosphorescent polymers and indicate that PFDMPE other than PF is a suitable polymeric host for the construction of e?cient red TADF polymers.
关键词： PFDMPE,electroluminescence,polymers,poly?uorene,triplet energy,PF,energy transfer,red-emitting,thermally activated delayed ?uorescence,poly(?uorene-co-3,3′-dimethyl diphenyl ether)
更新于2025-09-23 15:21:01
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Selective area laser-assisted doping of SiC thin films and blue light electroluminescence
摘要： Laser-assisted doping combined with annealing technique is used in selective areas to form a p–n junction on a SiC thin film grown by the pulsed laser deposition on a Si substrate at a temperature of 800 °C. This approach in an aluminum chloride solution and a phosphoric solution has resulted in p-SiC/n-Si and n-SiC/p-Si hetero-structures, respectively. Further, a functional in-plane p–n junction is realized side-by-side on the post-deposited SiC thin film. I–V characteristics by two probe technique showed the p–n diode characteristics. Blue light (400 nm) electroluminescence from the p–n junction on SiC thin film was observed in the forward biased condition. Further, an improvement in the I–V reverse characteristics was observed by illuminating the p–n SiC thin film with green/blue light.
关键词： pulsed laser deposition,laser assisted doping,SiC thin film,electroluminescence,silicon carbide,selective area doping
更新于2025-09-23 15:19:57
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High performances red phosphorescent organic light-emitting diodes with low operation voltage
摘要： In this work, we demonstrated an efficient device design strategy in improving the electroluminescent performances of red phosphorescent emitter iridium(III) bis(2-phenylquinoly-N,C2’)dipivaloylmethane (PQ2Ir(dpm)) by constructing predominant and supplementary light-emitting layers (EMLs). 4,4’,4’’-tris(carbazole-9-yl) triphenylamine (TcTa) and 4,7-dicarbazol-9-yl-[1,10]-phenanthroline (BUPH1) were selected as host materials of EMLs. Due to the well-designed double-EMLs device structure and the well-matched energy levels of selected materials, improved carriers’ balance and broadening recombination zone caused the low operation voltage and high device performances. Finally, the 4 wt% double-EMLs device obtained the highest brightness, external quantum efficiency, current efficiency, and power efficiency up to 29870 cd m-2, 12.18%, 19.74 cd A-1, and 25.84 lm W-1, respectively. At very low operation voltage of 3.4 V, this device realized the certain brightness of 1000 cd m-2 with power efficiency of 14.68 lm W-1.
关键词： recombination zone,carriers’ balance,electroluminescence,operation voltage
更新于2025-09-23 15:19:57
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The influence of electrode for electroluminescence devices based on all-inorganic halide perovskite CsPbBr<sub>3</sub>
摘要： Electroluminescence devices based all-inorganic halide perovskite material with the excellent luminescence performance have been studied extensively in recent years. However, the important role for the electrodes of electroluminescence devices is payed few attention by theoretical and experimental studies. Appropriate electrodes can reduce the Schottky barrier height to decrease the energy loss, and prevent the metal impurities from diffusing into the perovskite material to generate deep traps levels, which improves the luminous efficiency and lifetime of devices. In this paper, not only the interface effects between CsPbBr3 and common metal electrode (Ag, Au, Ni, Cu and Pt) are studied by first-principle calculations, but also the diffusion effects of metal electrode atom into the CsPbBr3 layer are also explored by nudged elastic band calculations. The calculated results show the metal Ag is more suitable for the cathode for CsPbBr3 electroluminescence devices, while the metal Pt is more applicable for the anode. Based on the overall consideration about the interface effects and diffusion effects of the CsPbBr3-metal electrode junctions, the essential principle provide a valuable reference how to select the suitable electrodes for other electroluminescence devices.
关键词： electroluminescence devices,diffusion effects,Schottky barrier height,CsPbBr3,all-inorganic halide perovskite,metal electrodes
更新于2025-09-23 15:19:57
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Surface Engineered Colloidal Quantum Dots Toward Complete Green Process
摘要： The rising demand for eradicating hazardous substances in the workplace has motivated vigorous researches on environmentally-sustainable manufacturing processes of colloidal quantum dots (QDs) for their optoelectronic applications. Despite remarkable achievements witnessed in QD materials (e.g., Pb- or Cd-free QDs), the progress in the eco-friendly process is far falling behind and thus the practical use of QDs. Herein, a complete “green” process of QDs, which excludes environmentally unfriendly elements from QDs, ligands, or solvents, is presented. The implant of mono-2-(methacryloyloxy)ethyl succinate (MMES) ligands renders InP/ZnSexS1-x QDs dispersed in eco-friendly polar solvents that are widely accepted in the industry while keeping photophysical properties of QDs unchanged. The MMES-capped QDs show exceptional colloidal stabilities in a range of green polar solvents that permit uniform inkjet printing of QD dispersion. In addition, MMES-capped QDs are also compatible with commercially available photo-patternable resins, and the cross-linkable moiety within MMES further facilitates the achievement in the formation of well-defined, micrometer-scale patterning of QD optical films. The presented materials, all composed of simple, scalable, and environmentally-safe compounds, promise low environmental impact during the processing of QDs, and thus will catalyze the practicable use of QDs in a variety of optoelectronic devices.
关键词： photo-patterning,electroluminescence devices,environmentally friendly processing,inkjet printing,quantum dots
更新于2025-09-23 15:19:57