Revealing structure correlation between ionic liquid and metal-organic framework matrix

Solid-state batteries are rising rapidly in response to the fast-increasing energy demand.Metal-organic framework(MOF)loaded with ionic liquids has brought new opportunities for solid-state batteries owing to its good interfacial compatibility and high ionic conductivity.MOF-808 is selected to be filled with Li-contained ionic liquid for structure and ion dynamics investigation using nuclear magnetic resonance(NMR)and X-ray diffraction.This study finds that the introduced ionic liquid would partially soften the matrix of MOF-808 and thus yield amorphous phase.By selective isotope replacement under cycling symmetric 6Li metal cell,Lit ion is observed to mainly go cross ionic liquid in the open channel of matrix under potential polarization.

Enhancing light yield of Tb^(3+)-doped fluoride nanoscintillator with restricted positive hysteresis for low-dose high-resolution X-ray imaging

Developing scintillators with high light yield(LY),superior irradiation stability,and weak afterglow is of significance for the realization of low-dose high-resolution X-ray excited optical luminescence(XEOL)imaging.Lanthanide doped fluoride nanoparticles possess low toxicity,superior environmental stability,facial fabrication process,and tunable emissions,which are appropriate candidates for the next generation nanoscintillators(NSs).However,the low LY and strong positive hysteresis greatly restrict their practical application.Here,we propose an effective strategy that engineers energy gap to significantly enhance the LY.Our results verify that the tetragonal LiLuF4 host benefits the crystal level splitting of Tb^(3+)ions,which greatly promotes the electrons population on the Tb^(3+):5D4 level followed by the enhanced LY.The LY of LiLuF4:Tb@LiLuF4 NSs is calculated to be~31,169 photons/MeV,which is much higher than the lead halide perovskite colloidal CsPbBr3(~21,000 photons/MeV)and LuAG:Ce(~22,000 photons/MeV)scintillators.Moreover,the positive hysteresis is remarkably restricted after coating a thin shell.The X-ray detection limit and spatial resolution are measured to be~21.27 nGy/s and~7.2 lp/mm,respectively.We further verify that this core/shell NS can be employed as scintillating screen to realize XEOL imaging under the low dose rate of 13.86μGy/s.Our results provide an effective route to develop high performance NSs,which will promote great opportunities for the development of low-dose high-resolution XEOL imaging devices.

Boosting the efficiency of quantum dot–sensitized solar cells over 15%through light-harvesting enhancement

How to improve the capacity of light-harvesting is still an important point and essential strategy for the assembling of high-efficiency quantum dot–sensitized solar cells(QDSCs).A believable approach is to implant new light absorption materials into QDSCs to stimulate the charge transfer.Herein,the few-layer black phosphorus quantum dots(BPQDs)are synthesized by electrochemical intercalation technology using bulk BP as source.Then the obtained BPQDs are deposited onto the surface of Zn–Cu–In–S–Se(ZCISSe)QD-sensitized TiO2 substrate to serve as another light-harvesting material for the first time.The experimental results have shown that BPQDs can not only increase the absorption intensity by photoanode but also reduce unnecessary charge recombination processes at the interface of photoanode/electrolyte.Through optimizing the size and deposition process of BPQDs,the champion power conversion efficiency of ZCISSe QDSCs is increased to 15.66%(26.88 mA/cm2,Voc=0.816 V,fill factor[FF]=0.714)when compared with the original value of 14.11%(Jsc=25.41 mA/cm^(2),Voc=0.779 V,FF=0.713).

Novel ultra-wideband fluorescence material:Defect state control based on nickel-doped semiconductor QDs embedded in inorganic glasses

In recent years,the development of an environmentally friendly quantum dots(QDs)embedded luminous solid by a simple method has attracted considerable attention.In this study,semiconductor ZnS QDs were successfully prepared in an inorganic matrix of amorphous glass,which yielded beneficial broadband emission in the long-wavelength region of the visible range.The strong red emission belonged to the defect state energy level of the ZnS QDs,which could be enhanced by incorporation of nickel ions into the fixed matrix to regulate the defects state.The novel material had a small self-absorption,wide excitation and emission ranges,and thus potential applications in light-conversion devices,luminescent solar concentrators,and solar cell cover glasses.

SrAl_(2)O_(4) crystallite embedded inorganic medium with super-long persistent luminescence,thermoluminescence, and photostimulable luminescence for smart optical information storage

As a leader of long persistent luminescence(LPL) materials, the optical properties of aluminate phosphor have remained unsurpassed for many years. As a powder material, its practical application will always be limited to the field of security signs. In this paper, the SrAl_(2)O_(4)∶Eu^(2+), Dy^(3+)inorganic solid material with comparable LPL properties to powder materials was obtained. The crystallization mechanism and crystallite micro-morphology of inorganic glass materials have been studied, and a new opinion is put forward that the large-size SrAl_(2)O_(4)crystallites in the glass matrix are stacked by rod-shaped crystals arranged in a regular direction. In addition,the SrAl_(2)O_(4)∶Eu^(2+), Dy^(3+)glass obtained cannot only collect high-energy photons but also is sensitive to lowenergy sunlight. The results show that the material exhibits superior performance in LPL, thermoluminescence,and photostimulable luminescence. Based on this property, a new application of this material in the field of information storage was explored. This paper has a certain reference value for the development and application of aluminate LPL materials in the field of smart optical information storage.

Pressure-induced bimetallic carbon nanotubes from metalorganic frameworks as optimized bifunctional electrocatalysts for water splitting

Carbon nanotubes(CNTs)have attracted great interest in numerous applications due to their excellent electronic and structural properties.However,harsh synthesis conditions and high energy consumption limit the further application of CNTs.Herein,we developed a facile and innovative strategy to generate CNTs by physically pressurizing metal-organic frameworks(MOFs)and then pyrolyzing.The synthesized bimetallic nitrogen/sulfur double-doped carbon nanotubes are denoted as Fe_(x)Co_(1-x)P(x=0.5,0.6,0.7,0.8,0.9).The introduction of pressure not only revolutionized the morphology of the electrocatalysts,but also enhanced the activity of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in alkaline solution.Fe_(0.6)Co_(0.4)-P exhibits superior OER and HER performances in 1.0 mol·L^(-1)KOH solution with overpotentials of 364 and 346 mV at 10 mA·cm^(-2),which are 28 and 5 mV lower than unpressurized Fe0.6Co0.4.

Hybrid coating SnO_(2)for enhanced Li ions storage

Anode SnO_(2)in lithium-ion batteries suffers from volume expansion and agglomeration.Here,the SnO_(2)nanoparticles are hybrided with ZrO_(2)particles by the support of carbon nanotube networks.The obtained SnO_(2)/C/ZrO_(2)composite shows improved electrochemical performances.Investigations reveal that the carbon nanotubes shorten the transmission path of electrons and Li^(+) ions.Ball milling with ZrO_(2)promotes the formation of nanosized SnO_(2)to weaken the internal strain change,being beneficial to buffering volume change during electrochemical cycling afterwards.High-resolution 6.7Li NMR investigations indicate that conversion and alloying reactions are stepwise involved for SnO_(2)/C/ZrO_(2)anode.The strategy of designing SnO_(2)/C/ZrO_(2)composite from the morphology-controlled metal-organic frameworks for energy storage widens the possibility to fabricate promising materials with enhanced performances.

Sunlight activated ultra-stable long persistent luminescence glass ceramic for outdoor information display

Natural sunlight activated persistent luminescence(PeL)is ideal candidate for optical information display in outdoors without the requirement of electric supply.Except the brightness and duration,the stability especially water resistance of the PeL materials is of significant importance for practical application,which remains a great obstacle up to date.Herein,we report a new sunlight activated PeL glass ceramic containing hexagonal Sr_(13)Al_(22)Si_(10)O_(66):Eu^(2+)crystals,which exhibits strong blue PeL and can last more than 200 h.The PeL can be charged by the full wavelengths located in AM 1.5G due to the broad distribution of traps in the crystal structure.The PeL is clearly observed by the naked eye even after 24 h upon sunlight irradiation irrespective of the weather,and the photoluminescence intensity only decreased~3.3%after storing in water for 365 d.We demonstrate its potential application for thermal and stress responsive display as well as long-term continuous security indication upon sunlight irradiation,which not only save vast energy and reduce environment pollution,but also are appropriate for outdoor usage.