- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Synthesis, Characterization and Luminescence Studies of Metal-Diimine Complexes
摘要： Metal complexes have attracted great interest due to their potential application as luminescent materials in organic light emitting diodes (OLED) in the present technological displays. Through systematic study on the variation of ligands, structural and bonding modes of different metal centers, the structure-property relationships of the various classes of luminescent transition metal complexes can be obtained. The present research reports the synthesis and luminescence studies of some metal-diimine complexes. A diimine ligand namely N,N?-bis-(salycylidene)-4,4?-diaminodiphenylether between diaminodiphenylether with salicyldehyde in a 1:2 molar ratio. Subsequently, the corresponding Zn(II) (4a) and Cd(II) (4b) complexes were prepared ratio of metal:ligand:NaOH=1:1:2. The synthesized ligand and all the complexes were characterized by CHN elemental analysis, 1H and 13C NMR, UV-Vis and FTIR spectroscopic data and molar conductivity measurements. The spectroscopic data suggested that the ligands acted as N2O2-tetradentate, coordinating to the metal atom through both the azomethine N atoms and hydroxyl O atoms. The fluorescence properties of the synthesized metal complexes were investigated. The metal- diimine complexes displayed emission bands centered in the range of 465-490 nm with higher luminescence intensity due to ligand metal-metal charge transfer transitions (LMCT). The relatively large Stoke’s shift observed probably indicates that the energy absorbed by the organic ligands was transferred efficiently to the metal ions and merits them to be used as promising emitters in OLED.
关键词： Binuclear complexes,OLED’s,Diimines,Electroluminescent materials
更新于2025-09-23 15:21:21
-
Thermophotonic cooling with light-emitting diodes
摘要： The currently ubiquitous light-emitting diodes (LEDs) have revolutionized the lighting industry. Contrary to common belief, however, LEDs are much more than just simple electricity-to-light converters. They are solid-state thermodynamic machines, theoretically capable of continuous and near-reversible energy conversion between electrical, thermal and optical energy. For over 50 years, the possibility of exploiting LEDs as efficient solid-state coolers has remained largely out of reach due to the high-material-quality requirements and commercial focus on light emission. Recent promising advances in electroluminescent cooling by LEDs, however, suggest that the remaining challenges in the area may be surmountable and practical cooling could be feasible. This Perspective discusses recent achievements in electroluminescent cooling, outlining the expected promise, the remaining challenges and their potential solutions.
关键词： solid-state thermodynamic machines,light-emitting diodes,electroluminescent cooling,LEDs,thermophotonic cooling
更新于2025-09-23 15:19:57
-
Quantum Dots and Applications
摘要： It is the unique size-dependent band gap of quantum dots (QDs) that makes them so special in various applications. They have attracted great interest, especially in optoelectronic ?elds such as light emitting diodes and photovoltaic cells, because their photoluminescent characteristics can be signi?cantly improved via optimization of the processes by which they are synthesized. Control of their core/shell heterostructures is especially important and advantageous. However, a few challenges remain to be overcome before QD-based devices can completely replace current optoelectronic technology. This Special Issue provides detailed guides for synthesis of high-quality QDs and their applications. In terms of fabricating devices, tailoring optical properties of QDs and engineering defects in QD-related interfaces for higher performance remain important issues to be addressed.
关键词： quantum dots,luminescent solar concentrator,photoluminescent,photovoltaic,photodetector,charge transfer,electroluminescent
更新于2025-09-23 15:19:57
-
Cation-Exchange-Derived InGaP Alloy Quantum Dots toward Blue Emissivity
摘要： In contrast to a substantial progress of heavy metal-free green and red emitters exclusively from indium phosphide (InP) quantum dots (QDs), the development of non-Cd blue QDs remains nearly unexplored. Synthesis of blue InP QDs with a bright, deep-blue emissivity is not likely viable, which is primarily associated with their intrinsic size limitation. To surmount this challenge, herein, the first synthesis of blue-emissive ternary InGaP QDs through In3+-to-Ga3+ cation exchange strategy is implemented. Pre-grown InP QDs turn out to be efficiently Ga-alloyed at a relatively low temperature of 280oC in the presence of Ga iodide (GaI3) and degree of Ga alloying is also found to be systematically adjustable by varying GaI3 amount. Such cation-exchanged InGaP cores are surface-passivated sequentially with ZnSeS inner and ZnS outer shell. As the amount of GaI3 added for cation exchange increases, the resulting double-shelled InGaP/ZnSeS/ZnS QDs produce consistent blue-shifts in photoluminescence (PL) from 475 to 465 nm, while maintaining high PL quantum yield in the range of 80?82%. Among a series of QD samples above 465 nm-emitting InGaP/ZnSeS/ZnS QDs are further employed as an emitting layer of all-solution-processed electroluminescent device. This unprecedented InGaP QD-based blue device generates maximum values of 1038 cd/m2 in luminance and 2.5% in external quantum efficiency.
关键词： InGaP alloy quantum dots,electroluminescent device,blue emissivity,cation exchange
更新于2025-09-19 17:13:59
-
New xanthone derivatives as host materials: Improvement of carriers balance for high-efficiency green phosphorescent OLEDs using two host materials
摘要： Three new xanthone derivatives, 3-(4-(diphenylamino)-9H-carbazol-9-yl)-9H-xanthen-9-one (XanCarDipha), 2-(4-(4-(diphenylamino)-9H-carbazol-9-yl)phenyl)-9H-xanthen-9-one (p-XanCarDipha), and 2-(3-(4-(diphenylamino)-9H-carbazol-9-yl)phenyl)-9H-xanthen-9-one (m-XanCarDipha) as host materials are designed and synthesized, and they are applied to the development of green phosphorescent organic light-emitting diodes (PHOLEDs). Due to the different connection methods of carbazole units and xanthone units of the compounds, the efficiency curves of XanCarDipha exhibited significantly difference compared to other two materials after above three new materials are made into OLED devices as single host in emitting layer (EML). In EML, a PHOLED using 1: 1 p-XanCarDipha: CarTria as double host and doped with 12 wt% tris(2-phenylpyridine) iridium as a guest material can achieve the uppermost external quantum efficiency (EQE) of 20.93% , the uppermost current efficiency (CE) of 77.40 cd A-1, and the uppermost power efficiency (PE) of 93.15 lm W-1. Compared with corresponding highest luminous efficiency of devices using p-XanCarDipha as single host material (16.86%, 62.55 cd A-1 and 42.60 lm W-1), the efficiency of double-host materials has been significantly enhanced. Meanwhile, the glass transition temperatures (Tg) of the three new host materials are all higher than 120 °C, indicating that they should have good thermal stability in the device application. This work not only provides a design direction for xanthones, but also demonstrates its superior performance on OLED devices when they combined with another host material.
关键词： Double-host materials,Electroluminescent properties,PHOLEDs,Carrier balance,Energy level
更新于2025-09-19 17:13:59
-
More Than 9% Efficient ZnSeTe Quantum Dot-Based Blue Electroluminescent Devices
摘要： We explore both synthesis of Cd-free blue quantum dots (QDs) with high-quality photoluminescence (PL) characteristics and fabrication of high-efficiency QD-light-emitting diodes (QLEDs). True blue (445 nm)-emissive, multishelled ZnSeTe QDs with a high PL quantum yield of 84% and sharp bandwidth of 27 nm are prepared. To obtain a better electron transport layer (ETL) material, surface of ZnMgO nanoparticles (NPs) is modified by additional Mg reaction, leading to the possible formation of Mg(OH)2 layer on the surface-modified ZnMgO (m-ZnMgO) NPs. The presence of Mg(OH)2 overlayer, origin for the desirably reduced electron mobility, is supposedly responsible for the improved charge balance of QD emissive layer (EML). The Mg(OH)2 layer is further found to alleviate the emission quenching of QD EML. Combining blue ZnSeTe QDs and m-ZnMgO NP ETL, highly bright, efficient blue QLEDs with the record luminance of 2904 cd/m2 and external quantum efficiency of 9.5% are demonstrated.
关键词： electron transport layer,Mg(OH)2 overlayer,electroluminescent devices,photoluminescence,ZnSeTe QDs,Cd-free blue quantum dots,QLEDs,ZnMgO nanoparticles
更新于2025-09-19 17:13:59
-
Photophysics and electroluminescence of red quantum dots diluted in a thermally activated delayed fluorescence host
摘要： A feasible, universal, and low-cost strategy for quantum dot light-emitting devices (QLEDs) was provided to significantly enhance the electroluminescent performances. The emissive layer consists of organic host materials and quantum dots (QDs), and then the efficient energy transfer process remarkably promotes the device performances. It is confirmed that a highly efficient QLED can be realized by a host–guest system without common hole transport layers. The red device based on the thermally activated delayed fluorescence host and QD guest achieved a peak external quantum efficiency of 7.4%. Further, by simply modifying PEDOT:PSS with poly(4-styrenesulfonic acid), the work-function can be easily elevated, accompanied with the boosted external quantum efficiency to 11.9%. It is believed that such performances originate simultaneously from reduced interfacial fluorescence quenching, elevated work-function and efficient F?rster resonance energy transfer in the host–guest system.
关键词： external quantum efficiency,electroluminescent performances,quantum dot light-emitting devices,QLEDs,thermally activated delayed fluorescence,F?rster resonance energy transfer,host–guest system
更新于2025-09-16 10:30:52
-
Synthesis and characterization of PEDOT:PSS/ZnO nanowires heterojunction on ITO coated plastic substrate for light-emitting diodes
摘要： In this paper we report on heterojunction between the hole transporting polymerpoly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS) and zinc oxide (ZnO) nanowires grown on an indium tin oxide (ITO) coated polyethylene terephthalate (PET) plastic substrate. For the fabrication of heterojunction simple and low cost solution methods are used. The deposited films and heterojunction are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), photoluminescence (PL) and electroluminescence (EL) measurements. Electroluminescent and photoluminescent spectra of the hybrid heterojunction show one ultraviolet (UV) near-band-edge emission peak. The current-voltage characteristic confirms the junction formation between the polymer and ZnO nanowires and shows good rectifying p-n junction diode type behaviour of the fabricated structure. The charge transfer process in heterojunctionis explained by band energy diagram.
关键词： ZnO nanowires,PEDOT: PSS,flexible electroluminescent diode,p-n- heterojunction
更新于2025-09-16 10:30:52
-
Synthesis, chemical, theoretical studies, electrochemical, electrical and optical characterization of novel oligomer 2,2’-((1E,1’E)(2,5-bis(octyloxy)-1,4-phenylenevinylene)bis(6-(E)-2-(vinylquinolin))quinoline for OLED applications
摘要： A fluorescent pentamer 5QnQnPV with one phenyl central donor group surrounded by four quinoline acceptor groups set in a quadrupolar A-π-A-π-D-π-A-π-A electronic structure was synthesized. This compound is an organic semiconductor and shows a wide band fluorescence emission that spans from the blue to the red region with a maximum peak centered at 509 nm. In addition, its HOMO (? 5.4 eV)/LUMO (? 3.5 eV) energy values, determined by cyclic voltammetry, optical gap EgOpt of 2.18 and theoretical DT-DFT studies indicated a potential for OLED fabrication. When such device was made with a ITO/PEDOT:PSS/5QnQnPV/Al configuration it displayed a maximum electroluminescent response at 860 nm. The structural and physical characterization of this compound was performed using 1H and 13C Nuclear Magnetic Resonance, Fourier Transformed Infrared Spectroscopy, Mass Spectroscopy and Atomic Force Microscopy.
关键词： organic semiconductor,Atomic Force Microscopy,Fourier Transformed Infrared Spectroscopy,Mass Spectroscopy,electroluminescent response,fluorescent pentamer,Nuclear Magnetic Resonance,OLED
更新于2025-09-11 14:15:04
-
P‐9.12: Status and trends for electroluminescent quantum dots
摘要： This presentation will provide an overview of Electroluminescent Quantum Dot (EL-QD) technology, through the prism of our patent landscape analysis, to point out the key players, the technical choices and the specificities they focus on?
关键词： quantum dots,patent,Wide color gamut,electroluminescent
更新于2025-09-11 14:15:04