查看更多>>摘要：It is essential to enhance the thickness of the absorber layer for perovskite solar cells(PSCs)to improve device performance and reduce industry refinement.However,thick perovskite films(＞1 μm)are difficult to be fabricated by employing traditional solvents,such as N,N-dimethylformamide(DMF),dimethyl sulfoxide(DMSO).Besides,it is a challenge to fabricate thick-film perovskite owing to the deteriorated surface morphology and serious defect density.Herein,a simple method was reported to deposit uniform pinhole-free perovskite films with a thickness of more than 2 μm utilizing the methy-lamine acetate(MAAc)ionic liquid as the solvent.Com-bined with methylammonium chloride(MACl)as an additive,thick-film perovskite with～2 μm in grain size and few grain boundaries(GBs)was prepared,which dramatically improved the perovskite crystal quality and enhanced carrier transport performance.The final PSCs exhibited a power conversion efficiency(PCE)of 20.16％.The device showed improved stability with 95％of its initial efficiency in a nitrogen environment over 5000 h.This work provides an alternative strategy to produce extremely efficient and stable thick-film PSCs.It can be believed that this device has great potential in the appli-cation of large areas and laminated PSCs.
查看更多>>摘要：Although pseudocapacitive manganese dioxide(MnO2)integrates the high-power merit of carbonaceous materials with the high-energy merit of battery-type materials,it still has a long way to go in achieving a more satisfactory balance of higher energy and power density,and in decoupling the relationship of structural character-istics with energy storage performance.To realize such goals,a bottom-up[WO6]-perturbed[MnO6]assembly strategy has been developed here due to their similar structure,yet mismatched lattice parameters.This facile protocol is capable of finely controlling the morphology and crystal structure of MnO2 by adjusting its internal[WO6]concentration.Therefore,the as-prepared Wx-MnO2 is treated as an ideal platform to scrutinize the correlations of the structure with the energy storage per-formance.The operando Raman spectra and finite element analysis have fully demonstrated the superiority of the locally ordered defects-enriched structure of W0.02-MnO2,which could reach a favorable balance between the ion diffusion equilibrium time and the number of active sites.As a result,the W0.02-MnO2 is able to deliver a high capacitance of 292 F·g-1 at a current density of 1 A·g-1 and a remarkable rate performance with a 60％ capacity retention at a current density of 50 A·g-1.The further unveiled structure-performance relationship provides a guideline for the design of better pseudocapacitive energy storage devices.
查看更多>>摘要：The conjugation of external species with two-dimensional(2D)materials has broad application pro-spects.In this study,we have explored the potential of noble metal/2D MOF heterostructures in hydrogen storage.Specifically,the MgH2-Ni-MOF@Pd system has shown remarkable hydrogen desorption/sorption performances,starting to liberate hydrogen at 181 ℃,which is 230 ℃ lower than that of pristine MgH2.Under the catalytic effect of Ni-MOF@Pd,the dehydrogenation apparent activation energy of MgH2 is noticeably decreased from(133.5±17.5)to(34.58±1.87)kJ·mol-1,and the hydrogenation apparent activation energy is reduced from(70.41+7.43)to(25.78±4.64)kJ·mol-1,which is lowered by 63.4％.The fully-dehydrogenated MgH2-Ni-MOF@Pd composite rapidly uptakes hydrogen,with 2.62 wt％at 100 ℃ and 6.06 wt％at 150 ℃ within 300 s,respectively.The mechanism analysis of MgH2 catalyzed by Ni-MOF@Pd has revealed that the transformation of Mg2Ni and Mg2NiH4 could act as a"hydrogen pump",providing numerous channels for fast diffusion and trans-port of hydrogen atoms.Moreover,in the dehydrogenation process,the element Pd reacts with MgH2 to form the Mg-Pd alloy phase,which makes MgH2 take precedence to decompose through the Mg-Pd alloy rather than self-de-composition,further reducing thermal stability and improving de/hydrogenation kinetics.The synergistic effect of Mg-Pd,Mg2Ni,and the special ultra-thin 2D sheet structure of the additive is the main reason for the good hydrogen storage property of MgH2-Ni-MOF@Pd.Our findings provide inspiration for designing efficient multi-functional additives with unique morphologies to optimize the hydrogen desorption/sorption behaviors of hydrogen storage materials.
查看更多>>摘要：Photothermal material applied in environmental governance has attracted growing attention.By combining the Stöber method and dopamine-triggered coating strat-egy,Co-Mn precursor was in situ incorporated into the polydopamine(PDA)layer over the surface of silica cores.Afterwards,a unique photothermal nanosphere with SiO2 core and thin carbon layer and dual Co-Mn oxides shell was allowed to form by sequential heat treatment in the inert atmosphere(SiO2@CoMn/C).The bimetallic fraction of Co/Mn in the carbon layer and post-treatment calcina-tion temperature was comprehensively tuned to optimize the peroxymonosulfate(PMS)activation performance of the catalyst.The state of bimetallic species was studied including their physical distribution,chemical valence,and interplay by various characterizations.Impressively,Co oxides appear as dominant monodispersed nanoparticles(～10 nm),while Mn with cluster-like morphology is observed to uniformly distribute over thin-layer carbon and adhered to the surface of SiO2 nanospheres(～250 nm).The calcined temperature could tune the oxidized state of Co species,leading to the optimization of the catalytic performance of introduced dual metal species.As a result,this obtained optimal catalyst integrated the advantages of exposed bimetallic CoMn species and N-doped thin carbon to deliver excellent catalytic PMS activation performance and photothermal synergetic catalytic mineralization abil-ity for diversiform pollutants.Further reactions condition controls and anion interference studies were conducted to identify the adaptability of the optimal catalyst.Moreover,the application of solar-driven interfacial water evaporation using optimal SiO2@Co3Mn1/C-600 catalyst was explored,showing a high water evaporation rate of 1.48 kg·m-2·h-1 and an efficiency of 95.2％,further revealing a compre-hensive governance functionality of obtained material in the complex pollution condition.
查看更多>>摘要：Regulating luminescent dynamics of lan-thanide-based luminescent materials via external stimuli is of great significance in the fields of optical thermometry and high-level anti-counterfeiting.However,it is still a huge challenge to realize multimodal emissions with tun-able color outputs from a single activator in simple struc-tures via smart dynamic control of photon transition processes.Herein,we present a mechanistic strategy to achieve multimodal luminescence of Er3+activators with color-switchable outputs in a non-core-shell host.Under the control of excitation dynamics(λex=980,808,1532,377 nm),the population among the intermediate energy levels of Er3+and the interaction between Er3+ and Yb3+could be precisely modulated through energy transfer and migration processes,leading to the generation of color-tunable multimodal luminescence upon diverse excitation modes(non-steady-state,single-/dual-wavelength steady,thermal activation).Inspired by its special luminescent performance,the as-obtained material exhibits great potential in noncontact thermometry,multimodal anti-counterfeiting,and high-capacity information encryption by performing a series of proof-of-concept experiments.Our findings might provide a conceptual model to modu-late the luminescent dynamics in a simple-structured sys-tem for the generation of color-adjustable multimodal emissions,which is convenient for the development of advanced luminescent materials toward versatile cutting-edge applications.
查看更多>>摘要：As a material with good biocompatibility,hydroxyapatite(HAP)can have optical properties after doping with various rare earth ions.As a biocompatible fluorescent material,doped HAP could have broad appli-cations in biological probes,drug delivery,optoelectronic materials,fluorescence anti-counterfeiting,and other aspects.In this paper,we put forward the preparation of HAP doped with terbium(Ⅲ)ions(Tb3+)by hydrothermal co-precipitation.By controlling the Tb3+doping content in reaction and the reaction time,the changes in HAP's structure,morphology,and luminescence properties under different conditions were studied.When the doping amount of Tb3+reached an optimal value,the dipole-quadrupole would occur and the concentration would be quenched.The control experiment showed that the optimal Tb3+content was 7.5 × 10-5 mol,which showed the best fluorescence performance.HAP,a non-luminous material,was rarely used in the field of fluorescent anti-counterfeiting and photoelectric devices.We proposed to prepare a lumines-cent aramid/polyphenylene sulfide(ACFs/PPS)fiber paper and a new light-emitting diode(LED)using the Tb-doped HAP phosphor.The composite sample exhibited an excellent stability and fluorescence performance,which also demonstrated a possibility of HAP applications in anti-counterfeiting and photoelectric.The introduction of Tb3+dopant HAP was done to give HAP optical properties and broaden the application range of HAP.
查看更多>>摘要：Cu-rich cell boundary phase is difficult to pre-cipitate evenly,resulting in a generally poor demagneti-zation curve squareness for Fe-rich Sm2Co17-type magnet,which is a key factor limiting the further improvement of magnetic energy product.In this study,we report that nanoscale strip-like ordered micro-domains distributed in 1∶7H disordered matrix phase of the solid solution pre-cursor is a new factor significantly affecting the precipi-tation and distribution of the cell boundary phase.Long strip-like and continuous micro-twin structure with twin boundaries neatly perpendicular to the C-axis is observed after sintering treatment.After solution treatment,sequential and long strip-like micro-twins gradually trans-form into disordered state along the basal plane,forming narrow disordered 1∶7H(TbCu7-type structure)phase between the separated strip-like ordered micro-domains.This disordering transformation takes place via broken down of the long strip-like ordered micro-domains,which is accomplished by narrowing along the width direction followed by reduction of the length.Furthermore,a new model revealing the effect of the ordered micro-domains on the formation of the cell boundary phase is proposed.Antiphase boundaries enriched in Cu have already existed in the precursor with long strip-like ordered micro-do-mains.Therefore,the Cu-rich cell boundary phase acting as strong pinning centers cannot be precipitated homoge-neously and distributed continuously after aging,resulting in a poor demagnetization curve squareness of Sm2Co17-type magnet.Our results indicate that significant broken down of the nanoscale ordered micro-domains in solution precursor is the key factor improving the distribution of cell boundary phase in Sm2Co17-type magnets.
查看更多>>摘要：N-doping has significant influence in manipu-lating the properties of TiO2,and this has stimulated the development of N-donor-functionalized titanium-oxo clusters(TOCs)as molecular models to study the struc-ture-property relationship.However,the structural type and photoresponsive application are still limited for such TOCs,especially regarding the high-nuclearity TOCs that contain structure unit of TiO2 for photocatalysis.Herein,we showed the synthesis of a series of high-nuclearity TOCs 1-3 compounds using π-conjugated 1,10-phenan-throline(phen)as chromophore and N-donor functional ligand.Compound 1 features cocrystal structure composed of one[Ti26]2+and half[Ti22]2+,which renders it as the first cocrystallized TOC containing two positively charged species and phen-functionalized TOC showing the highest nuclearity up to 37 Ti centers.By adjusting the synthetic conditions,the individual {Ti22} and(Ti26} clusters can also be isolated as Compounds 2 and 3,respectively.The core structure of {Ti22} is mainly constructed from four lacunary {Ti4} derived from pentagonal {Ti(Ti)5} unit,while {Ti26} is built from four complete {Ti(Ti)5} unit.Notably,a {Ti8O14} structure unit of anatase TiO2 can be identified in {Ti26}.Based on the unique structural features and proper photophysical and photochemical properties of Compounds 1-3,they are applied for photocatalytic sul-foxidation.Owing to the presence of anatase structure unit in {Ti26} and the synergistic effect from {Ti22} and {Ti26},the catalytic performance presents in the order of Com-pound 1＞Compound 3＞Compound 2.This work pro-vides excellent models to understand the structure-property relationship from the perspective of cocrystal-lization and Ti-O binding model and will further promote the application of TOCs as functional catalysts for organic transformation.
查看更多>>摘要：Based on the in-situ self-reduction and chemical stability,graphdiyne(GDY)and graphdiyne oxide(GDYO)are used as trapping agents to investigate the ability for recovering Au3+,Ag+,and Pd2+under different pH values and interfering ions.Under strong acidity at pH=1,these two agents demonstrate high select recovery towards the three precious metal ions,which could be in-situ reduced to nanoparticles(NPs).In addition,super-paramagnetic Fe3O4 NPs are deposited on the surfaces of GDY and GDYO.The magnetic responses enable GDY-Fe3O4 to recover precious metals conveniently and effi-ciently by the aid of an external magnetic field.This study also confirms the antibacterial activity of the as-recovered NPs deposited on GDY and GDYO against Escherichia coli and Staphylococcus aureus(1 × 105 colony-forming unit(CFU)·ml-1),and the antibacterial rates are 100％.This strategy of recovering precious metals and subse-quently reusing to combat pathogens will be of great sig-nificance for environmental remediation and biomedical applications.
查看更多>>摘要：Reducing thermal conductivity while avoiding adverse interfacial reactions during sintering is crucial for improving the thermoelectric performance of Bi2Te3-based composites.Inert ceramic nanoparticles are good candi-dates for achieving this goal.In this study,we designed and prepared a series of p-type Bi0.5Sb1.5Te3 nanocomposites decorated with Y2O3 ceramic nanoparticles via ball-milling dispersion and spark-plasma sintering.Owing to the chemical stability of the ceramics,no traces of atomic doping or interfacial reactions were observed.Transport measurements revealed that the Y2O3 nanoparticles dis-tributed along the grain boundaries acted as energy-de-pendent carrier-filtering centers to improve the scattering parameter and Seebeck coefficient,contributing to the elevated power factor even with a decreased electrical conductivity.Moreover,the incorporated Y2O3 nanoparti-cles and various defect structures they induced effectively strengthened the phonon scattering and suppressed the lattice thermal conductivity.Consequently,a peak figure of merit(ZT)of 1.23 at 313 K was achieved for 0.4％Y2O3/Bi0.5Sb1.5Te3,which is 13％higher than that of the matrix.In addition,the Vickers hardness of the composite material was 35％higher than that of the matrix.This study demonstrates the effectiveness of ceramic nanoparticles in synergistically improving the thermoelectric and mechan-ical properties,which may be further extended to other thermoelectric systems.
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