- 标题
- 摘要
- 关键词
- 实验方案
- 产品
过滤筛选
- 2020
- 2019
- 2018
- 2017
- 2016
- 2014
- atomic layer deposition
- Carbon dots
- charge transport
- cytotoxicity
- DFT
- NMR
- P3HT
- phosphors
- photoluminescence
- hydrothermal synthesis
- Nanomaterials and Technology
- Optoelectronic Information Materials and Devices
- Materials Science and Engineering
- Polymer Materials and Engineering
- Optoelectronic Information Science and Engineering
- Chemistry
- Mechanical Engineering
- Biomedical Engineering
- Pharmacy
- Intelligent Medical Engineering
- Chinese Academy of Sciences
- University of Jinan
- South China University of Technology
- Tianjin University
- Ecole Polytechnique Fédérale de Lausanne
- Beijing Technology and Business University
- Chongqing Medical University
- University of Science and Technology Beijing
- Shanghai Institute of Technology
- Zhejiang University
-
Boosting Efficiency of Near‐Infrared Organic Light‐Emitting Diodes with Os(II)‐Based Pyrazinyl Azolate Emitters
摘要： Tremendous effort has been devoted to developing novel near-infrared (NIR) emitters and to improving the performance of NIR organic light-emitting diodes (OLEDs). Os(II) complexes are known to be an important class of NIR electroluminescent materials. However, the highest external quantum efficiency achieved so far for Os(II)-based NIR OLEDs with an emission peak wavelength exceeding 700 nm is still lower than 3%. A new series of Os(II) complexes (1–4) based on functional pyrazinyl azolate chelates and dimethyl(phenyl)phosphane ancillaries is presented. The reduced metal-to-ligand charge transfer (MLCT) transition energy gap of pyrazinyl units in the excited states results in efficient NIR emission for this class of metal complexes. Consequently, NIR OLEDs based on 1–4 show excellent device performance, among which complex 4 with a triazolate fragment gives superior performance with maximum external quantum efficiency of 11.5% at peak wavelength of 710 nm, which represent the best Os(II)-based NIR-emitting OLEDs with peak maxima exceeding 700 nm.
关键词： N-donor,phosphorescence,osmium,near-infrared emission,organic light-emitting diodes
更新于2025-09-11 14:15:04
-
Dynamical processes related to viscous flow in a supercooled arsenic selenide glass-forming liquid: Results from high-temperature 77Se NMR spectroscopy
摘要： Dynamical processes in supercooled AsSe9 liquid are studied using 1D and 2D 77Se NMR spectroscopic techniques. The results demonstrate the coexistence of two distinct dynamical processes: one is a slow process related to the chemical exchange between the various Se environments by bond scission/renewal and the other is the fast Se chain segmental motion, which leads to the rapid averaging of the chemical shift anisotropy. The timescales of these two processes become increasingly similar as the glass transition is approached from above. The slow process is found to be closely coupled to viscosity over the entire temperature range of investigation and its activation energy is consistent with the Se-Se/As bond energies. On the other hand, the activation energy of the fast process is significantly higher, which may be indicative of its cooperative nature. This process becomes coupled to viscosity only in the immediate vicinity of the glass transition.
关键词： Supercooled liquid,Relaxation,Chalcogenide,Viscous flow,Glass transition,NMR spectroscopy
更新于2025-09-11 14:15:04
-
Divalent europium-doped near-infrared-emitting phosphor for light-emitting diodes
摘要： Near-infrared luminescent materials exhibit unique photophysical properties that make them crucial components in photonic, optoelectronic and biological applications. As broadband near infrared phosphors activated by transition metal elements are already widely reported, there is a challenge for next-generation materials discovery by introducing rare earth activators with 4f-5d transition. Here, we report an unprecedented phosphor K3LuSi2O7:Eu2+ that gives an emission band centered at 740 nm with a full-width at half maximum of 160 nm upon 460 nm blue light excitation. Combined structural and spectral characterizations reveal a selective site occupation of divalent europium in LuO6 and K2O6 polyhedrons with small coordination numbers, leading to the unexpected near infrared emission. The fabricated phosphor-converted light-emitting diodes have great potential as a non-visible light source. Our work provides the design principle of near infrared emission in divalent europium-doped inorganic solid-state materials and could inspire future studies to further explore near-infrared light-emitting diodes.
关键词： divalent europium,Near-infrared luminescent materials,4f-5d transition,light-emitting diodes,phosphor
更新于2025-09-11 14:15:04
-
Designing High‐Performance LED Phosphors by Controlling the Phase Stability via a Heterovalent Substitution Strategy
摘要： Phosphor-converted white light-emitting diodes (LEDs) are currently playing key roles in the lighting and display industries and trigger urgent demands for the discovery of “good” phosphors with high quantum efficiency, improved thermal stability, and controllable excitation/emission properties. Herein, a general and efficient heterovalent substitution strategy is demonstrated in K2HfSi3O9:Eu2+ achieved by Ln3+ (Ln = Gd, Tb, Dy, Tm, Yb, and Lu) doping to optimize luminescence properties, and as an example, the Lu3+ substitution leads to improvement of emission intensity and thermal stability, as well as tunable emission color from blue to cyan. The structural stability and Eu2+ occupation via Lu3+ doping have been revealed by the structural elaboration and density functional theory calculations, respectively. It is shown that heterovalent substitution allows predictive control of site preference of luminescent centers and therefore provides a new method to optimize the solid-state phosphors for LEDs.
关键词： phosphors,photoluminescence,white light-emitting diodes
更新于2025-09-11 14:15:04
-
Charge Transport and Extraction of Bilayer Interdiffusion Heterojunction Organic Solar Cells
摘要： Bilayer interdiffusion heterojunction with the structure of donor-rich region near the anode and acceptor-rich region near the cathode, could weaken energy level barrier between active layer and electrode, and improve the performance of organic solar cells. In this study, the poly (3-hexylthiophene) (P3HT) / [6:6]-phenyl-C61-butyric acid (PC61BM) bilayer interdiffusion heterojunction organic solar cells were prepared by using orthogonal solvent method, and the charge transport and extraction characteristics were investigated detailedly. The transient photovoltage/transient photocurrent measurements showed that the bilayer interdiffusion heterojunction devices have longer carrier recombination lifetime and shorter charge extract time, and higher carrier mobility of bilayer interdiffusion device was verified by photo-induced charge carrier extraction by linearly increasing voltage technology. The results indicated that the improved heterojunction structure of bilayer interdiffusion devices could reduce carrier recombination and improve charge transport and extraction efficiency. The performance of bilayer interdiffusion device was enhanced obviously, and about 19.8 % power conversion efficiency improvement was achieved as compared with the bulk device. Bilayer interdiffusion heterojunction provide an efficient device structure to optimize performance of organic solar cells.
关键词： Bilayer interdiffusion heterojunction,PC61BM,organic solar cells,P3HT,charge extraction,charge transport
更新于2025-09-11 14:15:04
-
Layer-Dependent Optoelectronic Properties of 2D van der Waals SnS Grown by Pulsed Laser Deposition
摘要： Layered metal monochalcogenides have attracted significant interest in the 2D family since they show different unique properties from their bulk counterparts. The comprehensive synthesis, characterization, and optoelectrical applications of 2D-layered tin monosulfide (SnS) grown by pulsed laser deposition are reported. Few-layer SnS-based field-effect transistors (FETs) and photodetectors are fabricated on Si/SiO2 substrates. The premium 2D SnS FETs yield an on/off ratio of 3.41 × 106, a subthreshold swing of 180 mV dec?1, and a field effect mobility (μFE) of 1.48 cm2 V?1 s?1 in a 14-monolayer SnS device. The layered SnS photodetectors show a broad photoresponse from ultraviolet to near-infrared (365–820 nm). In addition, the SnS phototransistors present an improved detectivity of 9.78 × 1010 cm2 Hz1/2 W?1 and rapid response constants of 60 ms for grow-time constant τg and 10 ms for decay-time constant τd under extremely weak 365 nm illumination. This study sheds light on layer-dependent optoelectronic properties of 2D SnS that promise to be important in next-generation 2D optoelectronic devices.
关键词： phototransistors,field effect transistors,2D materials,tin monosulfide,p-type FETs
更新于2025-09-11 14:15:04
-
Synthesis, spectral characterization (FT-IR and NMR) and DFT (Conformational analysis, molecular structure, HOMO-LUMO, UV-vis, NLO) computational studies on 2,2’-((1E,1’E)-phenazine-2,3 dilbis(azanylylidene))bis(methanyly- lidene))diphenol
摘要： A new Schiff base was synthesized for the first time by the phenazine-2,3-diamine and 2-hydroxy benzaldedye in ethanol (1:1). The structure of Schiff bases was experimentally characterized by using UV-vis, IR, 1H NMR and 13C NMR spectroscopic methods. Further, the synthesized compound was subjected to DFT for better understanding of the molecular architecture and optoelectronic properties. The optimized geometric parameters supported the available experimental values. The Mulliken and MEP analyses are utilized to identify reactive sites of title molecule. The energetic behaviors of compound 3 in hexane, chloroform, methanol solvents and gas phase were examined using by time-dependent DFT (TD-DFT) method by applying the polarizable continuum model (PCM). The calculated ΔE energies exposed that charge transfer takes place within the molecule. In addition to the polarizability and hyperpolarizability have been calculated which exhibit that compounds possess non-linear optical nature.
关键词： Schiff Base,MEP,HOMO-LUMO,DFT,Mulliken Charge
更新于2025-09-10 09:29:36
-
Two N,N-chelated difluoroboron complexes containing phenanthroimidazole moiety: Synthesis and luminescence properties
摘要： Two new N,N-chelated difluoroboron complexes, PIBF2-Cz and PI-BODIPY, containing phenanthroimidazole moiety were synthesized and characterized by elemental analysis, NMR spectroscopy and MS. Their photophysical and electrochemical properties and thermal stabilities were investigated systematically. The results showed that these N,N-chelated difluoroboron complexes not only exhibit excellent thermal stabilities but also emit strong green emissions with photoluminescence quantum efficiency of 95.71% and 67.22% in chloroform solutions. Furthermore, based on these N,N-chelated difluoroboron complexes, the green organic light-emitting devices with a configuration of ITO/NPB (20 nm)/TBADN: difluoroboron complex (x wt%, 30 nm)/TPBi (30 nm)/Liq (2 nm)/Al (100 nm) have been successfully fabricated by vacuum-deposition method, in which the devices fabricated from PIBF2-Cz exhibited the best electroluminescence performance with a maximum brightness of 20290 cd/m2 and a maximum luminous efficiencies of 7.97 cd/A and a maximum external quantum efficiency (EQE) of 1.88%.
关键词： Photoluminescence,Difluoroboron complex,Electroluminescence,Phenanthroimidazole
更新于2025-09-10 09:29:36
-
Effect of surface passivation process for AlGaN/GaN HEMT heterostructures using phenol functionalized-porphyrin based organic molecules
摘要： In this work, we investigate an unexplored possibility of passivating the charged surface states on AlGaN/GaN high electron mobility transistor (HEMT) heterostructures by using organic molecules. This has further led to remarkable enhancement in the electrical properties of rectifying metal-semiconductor contacts on AlGaN/GaN. Phenol functionalized Zinc metallated-Tetra Phenyl Porphyrin (Zn-TPPOH) organic molecules were adsorbed on AlGaN/GaN via the solution phase to form a molecular layer (MoL). The presence of the MoL was confirmed using X-ray Photoelectron Spectroscopy (XPS). The thickness of the MoL was assessed as ～1 nm, using Spectroscopic Ellipsometry and cross-sectional Transmission Electron Microscopy. XPS peak-shift analyses together with Kelvin Probe Force Microscopy revealed that the molecular surface modification reduced the surface potential of AlGaN by approximately 250 meV. Consequently, the Barrier height (ideality factor) of Ni Schottky diodes on AlGaN/GaN was increased (reduced) significantly from 0.91 ± 0.05 eV (2.5 ± 0.31) for Ni/AlGaN/GaN to 1.37 ± 0.03 eV (1.4 ± 0.29) for Ni/Zn-TPPOH/AlGaN/GaN. In addition, a noteworthy decrement in the reverse current from 2.6 ± 1.93 μA to 0.31 ± 0.19 nA at ?5 V (～10 000 times) was observed from Current-Voltage (I-V) measurements. This surface-modification process can be fruitful for improving the performance of AlGaN/GaN HEMTs, mitigating the adverse effects of polarization and surface states in these materials.
关键词： AlGaN/GaN,HEMT,Schottky barrier height,surface passivation,organic molecules,reverse current
更新于2025-09-10 09:29:36
-
Preparation of α-Linolenic-Acid-Loaded Water-in-Oil-in-Water Microemulsion and Its Potential as a Fluorescent Delivery Carrier with a Free Label
摘要： Our previous work has demonstrated that α-linolenic acid (ALA)-loaded oil-in-water (O/W) microemulsion could enhance ALA antioxidant capacity. Meanwhile, we also observed that synthesized microemulsion itself had ?uorescence. In this work, we have prepared a multiple water-in-oil-in-water (W/O/W) microemulsion to further enhance ALA antioxidant capacity and activate this delivery carrier application potential with a free label. The compositions of primary water-in-oil (W/O) microemulsion were obtained using pseudo-ternary phase diagrams, and then W/O/W microemulsion was prepared adopting the “two-step heterotherm method”. The conductivity of W/O/W microemulsion was measured to lie between 250.0 and 350.0 μs/cm. The spherical droplets with a mean particle diameter of 10.0?20.0 nm were con?rmed by transmission electron microscopy and dynamic light scattering. Nuclear magnetic resonance con?rmed that ALA di?used to the multiple water?oily interface simultaneously. In addition, the in vitro release and antioxidant capacity measurements of ALA-loaded W/O/W microemulsion concluded the sustained-release e?ect and excellent antioxidant capacity. The ?uorescent intensity of W/O/W microemulsion was markedly increased in comparison to O/W microemulsion. The synthesized microemulsion could lead to important applications and have advantages of a label-free ?uorescent carrier for optical imaging purposes.
关键词： ALA-loaded W/O/W microemulsion,?uorescent delivery carrier,characterization,antioxidant capacity
更新于2025-09-10 09:29:36