Long Lifetime Ultracold Plasma Produced by a Nanosecond Laser in a Supersonic Nitric Oxide Molecular Beam Environment

Ultracold plasma provides a possible route to approach the strongly-coupled regime under laboratory conditions. Normally, the lifetime of ultracold plasma is very limited due to plasma heating and expansion mechanisms. We present a new method to generate long lifetime ultracold plasmas consisting mainly of cations and anions. This plasma demonstrates a capability of traversing a DC barrier of up to 5 （or -3） V. The lifetime of this plasma is expected to be more than 250us. Finally, molecular dynamics （MD） simulation is used to explain how anions slow the expansion rate and prolong the lifetime of this plasma.

Linker aggregation engineering of TADF materials to tune carrierbalance for highly efficient organic LEDs with long operationallifetime

Thermally activated delayedfluorescence(TADF)molecules are regarded as promis-ing materials for realizing high-performance organic light-emitting diodes(OLEDs).The connecting groups between donor(D)and acceptor(A)units in D–A type TADF molecules could affect the charge transfer and luminescence performance of TADF materials in aggregated states.In this work,we design and synthesize four TADF molecules using planar and twisted linkers to connect the aza-azulene donor(D)and triazine acceptor(A).Compared with planar linkers,the twisted ones(Az-NP-T and Az-NN-T)can enhance A–A aggregation interaction between adjacent molecules to balance hole and electron density.As a result,highly efficient and stable deep-red top-emission OLEDs with a high electroluminescence efficiency of 57.3%and an impressive long operational lifetime(LT_(95)∼30,000 h,initial luminance of 1000 cd m^(-2))are obtained.This study provides a new strategy for designing more effi-cient and stable electroluminescent devices through linker aggregation engineering in donor–acceptor molecules.

A simple strategy to simultaneously improve the lifetime and activity of classical iridium complex for photocatalytic water-splitting

Herein,we design and synthesize a series of oligomers[Ir(ppy)2(dabpy)-ODPA]n(D1-n)by copolymerization of[Ir(ppy)2(dabpy)][PF6](D2)with 4,4′-Oxydiphthalic anhydride(ODPA),to resolve the problem of simultaneous improvement of sta-bility and activity of classical iridium complex for photocatalytic water-splitting.Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy,solid-state nuclear magnetic resonance,and gel permeation chromatography results indicate that the degree of polymerization(n)of D1-n could be tuned by the syn-thesis method.The best photocatalytic performance is reached by D1-n with n at of 2 and/or 3(D1-2/3),which exhibits a photocatalytic lifetime up to 676 h and a photocatalytic hydrogen evolution of 162055.1 Compared with classicalμmol⋅g-1.iridium complex D2,the photocatalytic lifetime of D1-2/3 is about 38 times longer and the photocatalytic activity is 1.3 times higher.Further increase of n leads to a decrease in both photocatalytic lifetime and activity.According to the spectro-scopic characterizations,photoelectrochemical experiments,and density functional theory calculation,the significantly enhanced photocatalytic performance of D1-2/3 originates from the oligomeric structure.The oligomer chain of D1-2/3 with suit-able length acts as a large steric hindrance to reduce the undesired photoinduced decomposition and prolong its lifetime.The possible coupling of adjacent Ir com-plexes in D1-2/3 lowers the energy gap and increases the utilization of visible light,which overcomes the adverse effect of large steric hindrance andfinally improve the activity.This workfirst provides a simple strategy for constructing oligomeric Ir photosensitizers to simultaneously achieve long lifetime and high activity,it will lay the foundation for the design of highly efficient photosensitizers in the future.

One-step rapid synthesis,crystal structure and 3.3 microseconds long excited-state lifetime of Pd1Ag28 nanocluster

Doping foreign atom(s)in metal nanoclusters is an effective strategy to engineer the properties and functionalities of metal nanoclusters.However,until now,to dope Pd atom into Ag nanoclusters remains a huge challenge.Here we develop a one-step rapid method to synthesize the Pd-doped Ag nanocluster with high yield.The prepared Pd1Ag28 nanocluster was characterized by mass spectroscopy,X-ray photoelectron spectroscopy,X-ray crystallography,fluorescence spectroscopy,ultraviolet-visible absorption spectroscopy and transient absorption spectroscopy.The nanocluster exhibits a perfect face-centered cubic(FCC)kernel structure with a tetrahedron-like shell.Of note,Pd1Ag28 nanocluster had an unexpectedly long excited-state lifetime of 3.3 microseconds,which is the longest excited-state lifetime for Ag-based nanoclusters S0 far.Meanwhile,the excellent near-infrared luminescence indicated the nanocluster has the potential in fluorescent bio-imaging.Besides,it was revealed that Pd1Ag28 nanocluster could be transformed into Au1Ag28 nanocluster via ion exchange reaction of AuPPhzCl with Pd1Ag28 nanocluster.This work provides an efficient synthetic protocol of alloy nanoclusters and wil contribute to study the effect of foreign atom on the properties of metal nanoclusters.

Progress in ceramic materials and structure design toward advanced thermal barrier coatings

Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat.However,the continuous pursuit of a higher operating temperature leads to degradation,delamination,and premature failure of the top coat.Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems.In this paper,the latest progress of some new ceramic materials is first reviewed.Then,a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth,ceramic sintering,erosion,and calcium–magnesium–aluminium–silicate(CMAS)molten salt corrosion.Finally,new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar,columnar,and nanostructure inclusions.The latest developments of ceramic top coat will be presented in terms of material selection,structural design,and failure mechanism,and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance,better thermal insulation,and longer lifetime.

The development of laser-produced plasma EUV light source

Extreme ultraviolet lithography(EUVL)has been demonstrated to meet the industrial requirements of new-generation semiconductor fabrication.The development of high-power EUV sources is a long-term critical challenge to the implementation of EUVL in high-volume manufacturing(HVM),together with other technologies such as photoresist and mask.Historically,both theoretical studies and experiments have clearly indicated that the CO 2 laser-produced plasma(LPP)system is a promising solution for EUVL source,able to realize high conversion efficiency(CE)and output power.Currently,ASML’s NXE:3400B EUV scanner configuring CO_(2) LPP source sys-tem has been installed and operated at chipmaker customers.Mean-while,other research teams have made different progresses in the development of LPP EUV sources.However,in their technologies,some critical areas need to be further improved to meet the requirements of 5 nm node and below.Critically needed improvements include higher laser power,stable droplet generation system and longer collector life-time.In this paper,we describe the performance characteristics of the laser system,droplet generator and mirror collector for different EUV sources,and also the new development results.

Fluorescence enhancement of Tb(Ⅲ) complex with a new β-diketone ligand by 1,10-phenanthroline

A novel β-diketone, 1-（3,4,5-trisbenzyloxy）benzoyl-5-benzoyl acetylacetone （TBAA）, and its corresponding binary Tb（Ⅲ） complex Tb（TBAA）3·2H2O and ternary complex Tb（TBAA）3Phen with 1,10-phenanthroline （Phen） were prepared. The ligand was characterized based on elemental analysis, FT-IR, and 1H NMR. The complexes were characterized with elemental analysis, FT-IR and thermogravimetry and derivative thermogravimetry （TG-DTG）. Photoluminescence measurements indicated that the energy absorbed by the organic ligand was efficiently transferred to the central Tb3＋ ions, and the complex showed intense and characteristic emissions due to the 5D4→7FJ transitions of the central Tb3＋ ions. Both complexes showed longer fluorescence lifetimes. After the introduction of the second ligand Phen group, the relative emission intensities and fluorescence lifetimes of the ternary complex Tb（TBAA）3Phen enhanced more obviously than that of the binary complex Tb（TBAA）3·2H2O. This indicated that the presence of the ligand TBAA and the second ligand Phen could sensitize fluorescence intensities of Tb（Ⅲ） ions, and the introduction of Phen group resulted in the enhancement of the fluorescence properties of the Tb（Ⅲ） ternary rare earth complex.

The construction of aggregation-induced charge transfer emission systems in aqueous solution directed by supramolecular strategy

Novel aggregation-induced charge transfer(CT) emission systems with long luminescence lifetime directed by supramolecular strategy have been successfully developed in water. The dimethylacridine-based electron donor(Br Ac) with excellent aggregation ability can co-aggregate with a triazine-based electron acceptor(TRZ) to form nanorods in water, which exhibit CT emission with long lifetime(τ = 0.92 μs).As for a similar electron donor(Qa Ac) with poor aggregation ability, water-soluble pillar[5]arene(WP5)can be introduced to promote the aggregation process, leading to the obvious CT emission with long lifetime(τ = 0.61 μs). In addition, structural modification of the acceptor with substituent groups possessing stronger electron-accepting capabilities will cause red-shift(about 50 nm) of the emission, which allows conveniently constructing long lifetime organic luminescent materials with different emission colors.