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First Member of an Appealing Class of Cyclometalated 1,3-Di-(2-Pyridyl)Benzene Platinum(II) Complexes for Solution-Processable OLEDs
摘要： The preparation and characterization of a new platinum(II) complex bearing a N^C^N-cyclometalating ligand and a thiolate coligand, namely 5-mesityl-1,3-di-(2-pyridyl)benzene and 1-phenyl-1H-tetrazole-5-thiolate, is reported. Its structure is determined by X-ray diffraction studies on a single crystal. This new complex exhibits green and red phosphorescence in dichloromethane solution (Φlum = 0.90) and in the solid state (Φlum = 0.62), respectively. In both cases the quantum yield is impressive showing for the first time that N^C^N platinum(II) complexes with a suitable thiolate can reach outstanding luminescent properties. The excellent solubility of this complex allows to fabricate green processable solution-OLEDs with maximum EQE similar to that obtained with more expensive vacuum techniques and, depending on its concentration, one can tune the color of the OLED. The molecular geometry, ground state, electronic structure, and excited electronic states of the complex, both as monomer and dimer aggregate in solution, are calculated by density functional theory (DFT) and time-dependent DFT approaches, giving insight into the electronic origin of the absorption spectra. Remarkably, the dimer is less sensitive to oxygen quenching than the monomer because the two 1-phenyl-1H-tetrazole fragments protect the platinum(II) centers, as suggested by a combination of luminescence studies and theoretical calculations.
关键词： thiolate ligand,DFT,luminescence,platinum(II) complex,OLED
更新于2025-09-23 15:21:01
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Dual-Emitting Quantum Dot Complex Nanoprobe for Ratiometric and Visual Detection of Hg2+ and Cu2+ ions
摘要： Herein we report the use of a dual emitting quantum dot complex (QDC; composed of blue emitting metal-methylsalicylaldimine complex being on the surface of orange emitting Mn2+-doped ZnS quantum dot) for ratiometric and visual detection of Hg2+ and Cu2+ ions - following the alterations in luminescence color, intensity ratio, chromaticity and hue of the QDC.
关键词： Hg2+ ions,Cu2+ ions,ratiometric detection,quantum dot complex,visual detection
更新于2025-09-23 15:21:01
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High Performances Thermally Activated Delayed Fluorescence Organic Light-emitting Diodes with Wide Gap Phosphorescent Complex as Sensitizer
摘要： In this work, we demonstrated the high performances electroluminescent (EL) devices based on orange-yellow thermally activated delayed fluorescence emitter (TXO-TPA) by utilizing an iridium complex (FK306) as sensitizer. Compared with reference devices without FK306, these co-doped devices displayed significant enhancement of EL performances, which could be attributed to optimized carriers' distribution and efficient energy transfer. In addition, the presence of FK306 molecules helps to broaden the exciton formation zone in EML2, thus suppressing the quenching of triplet excitons. Finally, the optimized co-doped double-EMLs device obtained superior EL performances with maximum current efficiency, power efficiency and external quantum efficiency up to 58.94 cd/A, 61.69 lm/W and 16.5%, respectively. Even at the high brightness of 1000 cd/m2, EL efficiency as high as 12.67 cd/A can still be retained by the same device.
关键词： Organic Light-emitting Diodes,Sensitizer,Wide Gap Phosphorescent Complex,Thermally Activated Delayed Fluorescence
更新于2025-09-23 15:21:01
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Modernization of the Thl-100 Laser System to Produce Powerful Terahertz Radiation
摘要： This paper presents the results of research on parameters of the THL-100 hybrid laser system of the visible spectrum with a view to modernizing it, in order to achieve the boundary parameters required for the pumping of non-linear crystals and production of the unprecedented THz radiation powers. The laser system consists of the Start-480M Ti:Sa starting complex and photodissociation XeF(C-A) amplifier with a 24 cm aperture. After modernization, the starting complex provides the spectrally limited radiation pulse of 60 fs at the first harmonic (950 nm) at energy of 25 mJ and 50 fs at the second harmonic (475 nm) at energy of 10 mJ. In the case of the positively chirped pulse with duration of 50 ps, the energy at the second harmonic is 3 mJ. When amplifying the negatively chirped radiation pulse in the XeF(C-A) amplifier at the wavelength of 475 nm with duration of 1.8 ps, the power of 40 TW is reached, and the maximum energy is 2 J. When amplifying the positively chirped pulse with duration of 50 ps, the highest energy of 3 J is achieved.
关键词： femtosecond complex,second harmonic,laser beam,hybrid laser system,gas amplifier,radiation energy
更新于2025-09-23 15:21:01
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A genetically encoded photosensitizer protein facilitates the rational design of a miniature photocatalytic CO2-reducing enzyme
摘要： Photosensitizers, which harness light energy to upgrade weak reductants to strong reductants, are pivotal components of the natural and artificial photosynthesis machineries. However, it has proved difficult to enhance and expand their functions through genetic engineering. Here we report a genetically encoded, 27 kDa photosensitizer protein (PSP), which facilitates the rational design of miniature photocatalytic CO2-reducing enzymes. Visible light drives PSP efficiently into a long-lived triplet excited state (PSP*), which reacts rapidly with reduced nicotinamide adenine dinucleotide to generate a super-reducing radical (PSP?), which is strong enough to reduce many CO2-reducing catalysts. We determined the three-dimensional structure of PSP? at 1.8 ? resolution by X-ray crystallography. Genetic engineering enabled the site-specific attachment of a nickel–terpyridine complex and the modular optimization of the photochemical properties of PSP, the chromophore/catalytic centre distance and the catalytic centre microenvironment, which culminated in a miniature photocatalytic CO2-reducing enzyme that has a CO2/CO conversion quantum efficiency of 2.6%.
关键词： quantum efficiency,photosensitizer protein,visible light,photocatalytic CO2-reducing enzymes,X-ray crystallography,nickel–terpyridine complex,genetic engineering
更新于2025-09-23 15:21:01
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Aqueous Sn-S Complex Derived Electron Selective Layer for Perovskite Solar Cells
摘要： A novel aqueous Sn-S complex solution was applied as precursor to fabricate SnO2 electron selective layers (ESLs) for the hybrid perovskite solar cells (PSCs). The tin and sulfur powder were directly dissolved in a (NH4)2S water solution to form Sn-S precursor. After depositon and annealing, the SnO2 film was formed, presenting as a low cost and enviromental friendly method for preparation of ESL. The films showed excellent transmittance at visible wavelength range. Moreover, the method exhibited high compatibility for doping using Cu, Cd, Li, and Zn elements. Zn doping (0.05 M) in the as-prepared SnO2 ESL significantly improved perovskite solar cells (PSCs) performance. The highest PCE of 13.17% was achived with 15% enhancement compared to that of undoped SnO2 ESL samples. TiCl4 modifications on SnO2 film improved photovoltaic performance to 14.45%, but resulted in the poor long-term stability, around 80% more degredation than that of PSCs based on Zn-doped SnO2 films.
关键词： SnO2,Sn-S complex,aqueous solution,perovskite solar cell,electron selective layer
更新于2025-09-23 15:21:01
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[IEEE 2019 International Conference on Power Electronics, Control and Automation (ICPECA) - New Delhi, India (2019.11.16-2019.11.17)] 2019 International Conference on Power Electronics, Control and Automation (ICPECA) - Machine Learning Based Islanding Detection for Grid Connected Photovoltaic System
摘要： This paper focus on developing a new islanding detection method with the help of machine learning and signal processing technique. The islanding detection method make sure that there is a proper remote monitoring of the grid integrated photovoltaic (PV) system. In case of grid fault or maintained of the grid, a proper informed signal is provided to various distributed generation (DG) networks so that they can disconnect with the grid and operate in isolated mode. A simulation of 1kW grid connected PV system is performed. The signal such as voltage, current and frequency are recorded at point of common coupling (PCC). The feature of recorded signals are extracted using wavelet transformation. The extracted features are used to form a islanding scenarios matrix. The matrix is further utilized to train a classi?er using machine learning algorithm. From the result it can be observed that the trained classi?er depicted 97.9% training accuracy with a training time of 16.9 sec which is better when compared with the literature. Further the trained classi?er is subjected to test with an unknown islanding condition to observe the robustness of the classi?er.
关键词： Islanding detection,complex tree,wavelet transform,Grid integrated photovoltaic system,distribution generation
更新于2025-09-23 15:21:01
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[IEEE 2020 International Workshop on Antenna Technology (iWAT) - Bucharest, Romania (2020.2.25-2020.2.28)] 2020 International Workshop on Antenna Technology (iWAT) - Numerical Analysis of Dielectric Post-Wall Waveguides
摘要： Functional post-wall waveguides that are formed by periodically distributed dielectric posts are numerically analyzed. The propagation constant and attenuation constant of the dielectric post-wall waveguide is rigorously calculated using our originally developed numerical method. The developed formulation is accurate and numerically very fast. Structural parameters of the dielectric post-wall waveguide are properly chosen in order to achieve the confinement of the field in the guiding region as strong as possible even in case of one-layered dielectric structure. The final goal of our investigations is to realize the functional dielectric post-wall waveguide-based filters, which are expected to have a practical application in THz region, where the metallic (PEC) rods are losing their properties.
关键词： dielectric post-wall waveguide,complex waves,modal analysis,periodic structure
更新于2025-09-23 15:21:01
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AC Impedance Spectroscopy, Conductivity and Optical Studies of Sr doped Bismuth Ferrite Nanocomposites
摘要： Effect of Sr doping on the structural, optical, dielectric, impedance properties of citrate combustion reaction route prepared Bi1-xSrxFeO3 (BSFO) nanocomposite has been investigated. The study of Fourier Transform Infrared Spectroscopy confirms the formation of perovskite structure of the Sr doped bismuth ferrite samples. SEM analysis shows decrease in grain size with increasing Sr concentration in BSFO nanocomposite. UV–visible absorption spectra in the spectral range 1.0–3.5 eV showed two doubly degenerate d–d transitions and two charge transfer transitions and optical band gap is found to decrease from 2.14 to 2.05 eV with increasing Sr concentration. Studies of frequency and temperature dependences of dielectric permittivity, impedance and electric modulus of the materials in broad frequency (20 Hz- 1 MHz) and temperature (30o C – 500oC) ranges using a complex impedance spectroscopy technique have provided interesting information on the contribution of the microstructure in these parameters. It has been observed that dielectric constant and dielectric losses decreases as the doping of Sr increased from x=0.1 to x=0.3 and attained a maximum value for BSFO (x = 0.1) sample. Impedance analysis indicates the presence of grain (bulk) and grain boundary resistive contributions which are found to increase with the increased Sr content. The ac conductivity of the samples is found to be frequency and temperature dependent and also vary with extent of Sr doping in BFO. Charge transport through short as well as long range conduction contributions has been indicated in different temperature regions of conductivity studies.
关键词： dielectric response,complex impedance spectroscopy,microstructure,Bismuth ferrite
更新于2025-09-23 15:21:01
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Super-assembled core-shell mesoporous silica-metal-phenolic network nanoparticles for combinatorial photothermal therapy and chemotherapy
摘要： Multimodal combinatorial therapy merges different modes of therapies in one platform, which can overcome several clinical challenges such as premature drug loss during blood circulation and significantly improve treatment efficiency. Here we report a combinatorial therapy nanoplatform that enables dual photothermal therapy and pH-stimulus-responsive chemotherapy. By super-assembly of mesoporous silica nanoparticles (MSN) with metal-phenolic networks (MPN), anti-cancer drugs can be loaded in the MSN matrix, while the outer MPN coating allows dual photothermal and pH-responsive properties. Upon near-infrared light irradiation, the MSN@MPN nanoplatform exhibits excellent photothermal effect, and demonstrates outstanding pH-triggered drug release property. In vitro cell experiments suggest the MSN@MPN system exhibits superior biocompatibility and can effectively kill tumor cells after loading anti-cancer drugs. Consequently, the MSN@MPN system shows promising prospects in clinical application for tumor therapy.
关键词： synergistic therapy,metal-polyphenol complex,photothermal therapy,pH-responsive
更新于2025-09-23 15:21:01