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- 实验方案
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Aggregation-induced Emission Polymers for High Performance PLEDs with Low Efficiency Roll-off
摘要： As the congener of organic light-emitting diodes, polymeric light-emitting diodes (PLEDs) possess a number of distinct merits such as low-cost wet fabrication process, which enable them applicable in large-area flexible display and lighting fields. However, most emissive polymers used in PLEDs suffer from the aggregation-caused quenching (ACQ) effect, which makes the device show large efficiency roll-off. In this work, two polymers of pTPE-TPA-Cz and pTPE-TPA-Flu featuring aggregation-induced emission (AIE) characteristics were facilely synthesized through Suzuki-Miyaura polycoupling reaction by incorporating the AIE unit of TPE-TPA in their main chains. The resultant polymers possess good film-forming ability, excellent thermal stability and high photoluminescence quantum yields (PLQY) in their film states, facilitating the fabrication of PLEDs through solution process. Indeed, the PLEDs using pTPE-TPA-Cz and pTPE-TPA-Flu as emitting layers (EMLs) could achieve a maximum external quantum efficiency (EQE) of 3.26% (doped EML) and current efficiency of 3.69 cd A-1 (non-doped EML). Notably, all the devices exhibit a quite low efficiency roll-off. This work indicates that AIE polymers are ideal candidates for the construction high performance PLEDs with low efficiency roll-off.
关键词： Aggregation-induced emission,Photoluminescence quantum yields,Solution process,Efficiency roll-off,Polymeric light-emitting diodes
更新于2025-09-23 15:21:01
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Graphene-assisted molecular beam epitaxy of AlN for AlGaN deep-ultraviolet light-emitting diodes
摘要： We report on the van der Waals epitaxy of high-quality single-crystalline AlN and the demonstration of AlGaN tunnel junction deep-ultraviolet light-emitting diodes directly on graphene, which were achieved by using plasma-assisted molecular beam epitaxy. It is observed that the substrate/template beneath graphene plays a critical role in governing the initial AlN nucleation. In situ reflection high energy electron diffraction and detailed scanning transmission electron microscopy studies confirm the epitaxial registry of the AlN epilayer with the underlying template. Detailed studies further suggest that the large-scale parallel epitaxial relationship for the AlN epilayer grown on graphene with the underlying template is driven by the strong surface electrostatic potential of AlN. The realization of high-quality AlN by van der Waals epitaxy is further confirmed through the demonstration of AlGaN deep-ultraviolet light-emitting diodes operating at 260 nm, which exhibit a maximum external quantum efficiency of 4% for an unpackaged device. This work provides a viable path for the van der Waals epitaxy of ultra-wide bandgap semiconductors, providing a path to achieve high performance deep-ultraviolet photonic and optoelectronic devices that were previously difficult.
关键词： AlGaN,AlN,molecular beam epitaxy,deep-ultraviolet,light-emitting diodes,van der Waals epitaxy
更新于2025-09-23 15:21:01
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[IEEE 2019 20th International Conference on Electronic Packaging Technology(ICEPT) - Hong Kong, China (2019.8.12-2019.8.15)] 2019 20th International Conference on Electronic Packaging Technology(ICEPT) - Self-Assembled Copper Nanoclusters-Based White Light Emitting Diodes With High Performance
摘要： Metal nanoclusters, composed of a few to a hundred atoms, whose size is close to the Fermi wavelength of electrons, have become a new type of phosphor materials due to their unique electronic structure and excellent performance. And metal nanoclusters have been applied in various applications, such as bioimaging, chemical biosensing, optoelectronic devices, etc. At present, researchers have synthesized and studied gold and silver nanoclusters, but Au and Ag nanoclusters have one drawback: expensive. At the same time, copper nanoclusters have attracted people's attention because of their non-toxicity, large Stokes shift and economy. In this paper, we fabricated 1-dodecanethiol (DT)-capped self-assembled copper nanoclusters in colloidal solution with yellow light emission and characterized the prepared self-assembled copper nanoclusters by UV–visible spectra, TEM and PL characterization methods. Self-assembled copper nanoclusters were used as color conversion layers for the manufacture of white light-emitting diodes. The prepared white LED has good color properties, the color rendering index was 79.3, the CIE color coordinates located at (0.3213,0.3255) and the color temperature was 6067K. This indicates that copper nanoclusters show potential for applications in white lighting emitting diodes as a new type of low-cost and superior photoluminescent material candidates.
关键词： Copper Nanoclusters,Photoluminescence,White Light Emitting Diodes,Quantum Dots
更新于2025-09-23 15:21:01
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Inkjet Printing Matrix Perovskite Quantum Dot Lighta??Emitting Devices
摘要： Perovskite light emitting devices have been expected to be utilized in the field of displays. In this work, a stable FA0.3Cs0.7PbBr3 perovskite quantum dot ink with optimized octane:dodecane cosolvent is obtained by introducing a trace amount of long-chain ligand of oleylamine (OAm) during the quantum dot purification process. A green electroluminescent matrix device with 120 pixels per inch (PPI) is realized from the ink by using an inkjet printing technique, exhibiting a luminance of 1233 cd m?2, a peak current efficiency of 10.3 cd A?1, and an external quantum efficiency of 2.8%. The results may suggest a possibility of making perovskite quantum dot displays by using the inkjet printing technique.
关键词： perovskite quantum dots,inkjet printing,light-emitting diodes
更新于2025-09-23 15:21:01
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A theoretical modeling analysis for triboelectrification controlled light emitting diodes
摘要： In this paper, we demonstrate the use of triboelectric nanogenerator (TENG) as a mean of mechanical light triggering to control InGaN-based light-emitting diodes (LEDs). Light extraction from the LED is two successive steps process. First, the voltage produced by the TENG is used to control the gate-to-source current of a MOSFET transistor through adjusting the transistor channel width and length. The second step is forwarding the drain-source current resulting from MOSFET transistor to the LED as its injection current to induce spontaneous emission from the LED surface to the air. Three LED colors are considered: red, green and blue. Significant emitted power from these InGaN-based LEDs in the RGB wavelength band is observed for both P-MOSFET and N-MOSFET transistor configurations. The emitted optical spectrum is controlled by optimizing the combined TENG-MOSFET-RGB LED geometry; dimensions and the bias voltage between the drain and source terminals of the MOSFET transistor. With recent advances in TENGs as an energy harvesting technology, it is expected that this study offers an approach to enhance the light extraction of various LED devices. With the enhancements in the performance of optoelectronic devices, the field of tribo- phototronics has attracted more attention, and in this work, we introduce the first theoretical framework, to the best of our knowledge, based on finite element modeling. This study provides significant insights into the working principles of tribo-Phototronic devices as well as guidelines for future device design.
关键词： MOSFET,Light-emitting diodes,Finite element modeling,Triboelectric nanogenerator,Tribo-phototronics
更新于2025-09-23 15:21:01
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Highly Efficient and Stable CsPbBr3 Perovskite Quantum Dots by Encapsulating in Dual-Shell Hollow Silica Spheres for WLEDs
摘要： Poor stability of CsPbX3 (X = Cl, Br or I) perovskite quantum dots (QDs) has greatly hindered their practical photoelectric applications, and how to improve it still remains a critical challenge. Herein, we encapsulated the CsPbBr3 QDs into a dual-shell hollow silica (SiO2) spheres via a simple successive ionic layer adsorption and reaction (SILAR) method. The hierarchical dual-shell structures permit CsPbBr3 QDs to be anchored on the interior of the SiO2 spheres while keeping the outside surface undisturbed, which can protect CsPbBr3 QDs from direct exposure to the atmosphere. Due to the comprehensive protection of dual-shell hollow SiO2 spheres, the CsPbBr3/SiO2 nanospheres exhibit markedly enhanced stability against light and heat, with residual PL intensity of 89% after continuous exposure of 72 h to UV light and 65% at 100?C heat treatment, respectively. In addition, an optimal PLQY of 89% is obtained with suppressed nonradiative recombination. Finally, the fabricated white light-emitting diodes (LEDs) device by employing CsPbBr3/SiO2 green phosphors could achieve a wide color gamut covering up to 136% of the NTSC standard. This work provides a novel SiO2-based encapsulation approach to solve the intrinsic instability issues of CsPbBr3 QDs, which has a profound impact on their practical applications.
关键词： photoluminescence quantum yield,CsPbBr3 quantum dots,dual-shell hollow silica spheres,stability,white light-emitting diodes
更新于2025-09-23 15:21:01
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Inverted Hybrid Light-Emitting Diodes Using Carbon Dots as Selective Contacts: The Effect of Surface Ligands
摘要： We describe the use of carbon dots (C-Dots) as selective contacts for electronic holes in inverted hybrid light-emitting diodes. Moreover, we have studied the effect of the C-Dots’ amine-derivative surface ligands and their impact on the device performance. The different surface ligands affect not only the optical properties of the C-Dots but also the device turn-on voltage and the luminance parameters despite not forming part of the emissive layer. For instance, the C-Dots capped with the aromatic ring p-phenylenediamine show unfavorable effects, whereas the effect of nonaromatic capping ligands depends upon the length of their molecular backbone.
关键词： capping ligands,amine-based ligands,light-emitting diodes,carbon dots,optoelectronic properties
更新于2025-09-23 15:21:01
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Highly Stable Red Quantum Dot Light Emitting Diodes with Long T <sub/>95</sub> Operation Lifetime
摘要： Quantum dot light-emitting diodes (QLEDs) with excellent performances such as external quantum efficiency (EQE) and lifetime have almost met the requirement of low brightness display. However, the short operation lifetime under high brightness limits the application of QLEDs in outdoor displays and lightings. Herein, we report a highly efficient, stable red QLED by using of lithium and magnesium co-doped as well as magnesium oxide shell-coated zinc oxide nanoparticle layer as electron transport layer (ETL). The optimized QLED has a high peak EQE of 20.6%, a low efficiency roll-off at high current, and a remarkably long lifetime T95 > 11000 h at 1000 cd m-2, which indicates the realization of the most stable red QLED up to now. The improvement in the long-term stability of the QLED is attributed to the use of co-doped and shell-coated zinc oxide ETL with reduced electron injection to improve the charge balance in device.
关键词： EQE,QLEDs,electron transport layer,ETL,magnesium oxide shell-coated zinc oxide,Quantum dot light-emitting diodes,external quantum efficiency,lithium and magnesium co-doped,ZLMO@MO,lifetime
更新于2025-09-23 15:21:01
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Colloidal Synthesis of Ternary Copper Halides Nanocrystals for High-Efficiency Deep-Blue Light-Emitting Diodes with a Half-Lifetime Above 100 Hours
摘要： Currently, the blue perovskite light-emitting diodes (PeLEDs) suffer from a compromise in lead-toxicity and poor operation stability, and most previous studies have struggled to meet the crucial blue NTSC standard. In this study, electrically-driven deep-blue LEDs (~445 nm) based on zero-dimensional (0D) Cs3Cu2I5 nanocrystals (NCs) were demonstrated with the color coordinates of (0.16, 0.07) and a high external quantum efficiency of ~1.12%, comparable with the best-performing blue LEDs based on lead-halide perovskites. Encouraged by the remarkable stability of Cs3Cu2I5 NCs against heat and environmental oxygen/moisture, the proposed device was operated in a continuous current mode for 170 h, producing a record half-lifetime of ~108 h. The device stability was further verified by an aggressive thermal cycling test (300?360?300 K) and a 35-day storage test. Together with the eco-friendly features and facile colloidal synthesis technique, the 0D Cs3Cu2I5 NCs can be therefore regarded as a promising candidate for deep-blue LEDs applications.
关键词： self-trapped excitons,light-emitting diodes,stability,Cs3Cu2I5 nanocrystals,deep-blue
更新于2025-09-23 15:21:01
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Evolution of pure hydrocarbon hosts: simpler structure, higher performance and universal application in RGB phosphorescent organic light-emitting diodes
摘要： In the field of phosphorescent organic light-emitting diodes (PhOLEDs), designing high-efficiency universal host materials for red, green and blue (RGB) phosphors has been quite a challenge. To date, most of the high-efficiency universal hosts reported incorporate heteroatoms, which have a crucial role in the device performance. However, the introduction of different kinds of heterocycles increases the design complexity and cost of the target material and also creates potential instability in the device performance. In this work, we show that pure aromatic hydrocarbon hosts designed with the 9,90-spirobifluorene scaffold are high-efficiency and versatile hosts for PhOLEDs. With external quantum efficiencies of 27.3%, 26.0% and 27.1% for RGB PhOLEDs respectively, this work not only reports the first examples of high-efficiency pure hydrocarbon materials used as hosts in RGB PhOLEDs but also the highest performance reported to date for a universal host (including heteroatom-based hosts). This work shows that the PHC design strategy is promising for the future development of the OLED industry as a high-performance and low-cost option.
关键词： RGB phosphors,PhOLEDs,external quantum efficiencies,phosphorescent organic light-emitting diodes,universal host materials,pure aromatic hydrocarbon hosts,9,90-spirobifluorene scaffold
更新于2025-09-23 15:21:01