Atomic-level quantitative analysis of electronic functional materials by aberration-corrected STEM

The stable sub-angstrom resolution of the aberration-corrected scanning transmission electron microscope(ACSTEM)makes it an advanced and practical characterization technique for all materials.Owing to the prosperous advancement in computational technology,specialized software and programs have emerged as potent facilitators across the entirety of electron microscopy characterization process.Utilizing advanced image processing algorithms promotes the rectification of image distortions,concurrently elevating the overall image quality to superior standards.Extracting high-resolution,pixel-level discrete information and converting it into atomic-scale,followed by performing statistical calculations on the physical matters of interest through quantitative analysis,represent an effective strategy to maximize the value of electron microscope images.The efficacious utilization of quantitative analysis of electron microscope images has become a progressively prominent consideration for materials scientists and electron microscopy researchers.This article offers a concise overview of the pivotal procedures in quantitative analysis and summarizes the computational methodologies involved from three perspectives:contrast,lattice and strain,as well as atomic displacements and polarization.It further elaborates on practical applications of these methods in electronic functional materials,notably in piezoelectrics/ferroelectrics and thermoelectrics.It emphasizes the indispensable role of quantitative analysis in fundamental theoretical research,elucidating the structure–property correlations in high-performance systems,and guiding synthesis strategies.

Effect of lanthanide contraction on a series of "sulfate-templated" transition-rare-earth metal clusters:Synthesis,structures and magnetic properties

Twelve novel transition-rare-earth metal clusters,formulated as [Ni_(18)Pr_(14)(μ_(3)OH)_(14)(dmpa)_(10)(mmt)_(10)(SO_(4))_(4)(CH_(3)COO)_(16)]·9CH_(3)OH·5H_(2)O(1,H_(3)dmpa=dimethylolpropionic acid,and Hmmt=2-me rcapto-5-methyl-1,3,4-thiadiazole) [Ni_(36)RE_(102)(OH)_(138)(mmt)_(18)(Hdmpa)_(30)(H_(2)dmpa)_(12)(CH_(3)COO)_(72)(NO_(3))_(36)(SO_(4))_(18)(H_(2)O)_(30)]·Br_(6)(RE=Nd(2),Sm(3),Eu(4) and Gd(5))[Ni_(12)RE_(10)(μ_(3)-OH)_(10)(dmpa)_(8)(mmt)_(8)(S(_(4))2(CH_(3)COO)_(8)(H_(2)O)_(4)]·8CH_(3)OH·7H_(2)O(RE = Tb(6),Dy(7),Ho(8),Er(9) and Y(10)) [Ni_(8)Pr_(8)(μ_(3)-OH)_(8)(mmt)_(8)(Hdpga)_(16)(CH3COO)_(8)]·8CH_(3)OH(11,H_(2)dpga=diphe nyl-glycolic acid),and [Ni_(16)Tb_(6)(μ_(3)-OH)_(24)(mmt)_(8)(Hdpga)_(4)(dpga)_(4)(CH_(3)COO)_(2)(NO_(3))_(4)(H_(2)O)_(2)]·12CH_(3)OH·5H_(2)O(12),were synthesized solvothermally by using different ligand combinations and rare earth nitrates.X-ray crystal structure analyses reveal that complexes 1 and 12 possess sandwich-like structure.Compounds 2-5 are isostructural and feature a hexagonal structure,shaped like a "Star of David".Isostructural 6-10 present ring-like structure,as well as the cluster 11.The structural variations of these complexes can be attributed to the effect of lanthanide contraction.Moreover,the template effect of SO_(4)^(2-) anion derived from the slow decomposition of Hmmt ligand also plays a significant role in the formation of cluster skeletons.The insitu mechanism for the generation of sulfate anion is briefly discussed.Meanwhile,the magnetic properties of complexes 2-11 were studied which show typical antiferromagnetic interactions.

Enhancing electrolyte ion diffusion via direct ink writing pillar array structure of graphene electrodes for high-performance microsupercapacitors

The graphene-based microsupercapacitors(MSCs)suffer from graphene aggregation issue in electrodes.It reduces the electrolyte ions transportation in the electrodes to degrade the charge storage ability of MSCs,hampering their practical application.Increasing the electrolyte ions transportation in the electrodes can boost the charge storage ability of MSCs.Herein,we design and experimentally realize pillar array structure of graphene electrodes for MSCs by direct ink writing technology.The graphene electrodes with pillar array structure increase the contact area with electrolyte and short the electrolyte ions transport path,facilitating electrolyte ions transport in electrodes.The MSCs exhibit high areal capacitance of 25.67 mF·cm^(−2),high areal energy density of 20.54μWh·cm^(−2),and high power density of 1.45 mW·cm^(−2).One single MSCs can power timer for 10 min and pressure sensor more than 160 min,showing high practical application possibility.This work provides a new avenue for developing high performance MSCs.