Tuning coherent-phonon heat transport in LaCoO3/SrTiO3 superlattices

Accessing the regime of coherent phonon propagation in nanostructures opens enormous possibilities to control the thermal conductivity in energy harvesting devices, phononic circuits, etc. In this paper we show that coherent phonons contribute substantially to the thermal conductivity of LaCoO3/SrTiO3 oxide superlattices, up to room temperature. We show that their contribution can be tuned through small variations of the superlattice periodicity, without changing the total superlattice thickness. Using this strategy, we tuned the thermal conductivity by 20% at room temperature. We also discuss the role of interface mixing and epitaxial relaxation as an extrinsic, material dependent key parameter for understanding the thermal conductivity of oxide superlattices. © 2021 The Authors. Published by American Chemical Society

Tuning Coherent-Phonon Heat Transport in LaCoO3/SrTiO3Superlattices

| openaire: EC/H2020/734187/EU//SPICOLOST Funding Information: This work has received financial support from Ministerio de Economía y Competitividad (Spain) under project Nos. MAT2016-80762-R and PID2019-104150RB-I00, Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2019-2022, ED431G 2019/03), the European Union (European Regional Development Fund-ERDF), and the European Commission through the Horizon H2020 funding by H2020-MSCA-RISE-2016- Project No. 734187-SPICOLOST. E.L. is a Serra Húnter Fellow (Generalitat de Catalunya). D.B. acknowledges financial support from MINECO (Spain) through an FPI fellowship (BES-2017-079688). V.P. and A.O.F. were supported by the MINECO of Spain through the project PGC2018-101334-B-C21. A.O.F. thanks MECD for the financial support received through the FPU grant FPU16/02572. This work was carried out in part through the use of the INL User Facilities. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society.Accessing the regime of coherent phonon propagation in nanostructures opens enormous possibilities to control the thermal conductivity in energy harvesting devices, phononic circuits, etc. In this paper we show that coherent phonons contribute substantially to the thermal conductivity of LaCoO3/SrTiO3 oxide superlattices, up to room temperature. We show that their contribution can be tuned through small variations of the superlattice periodicity, without changing the total superlattice thickness. Using this strategy, we tuned the thermal conductivity by 20% at room temperature. We also discuss the role of interface mixing and epitaxial relaxation as an extrinsic, material dependent key parameter for understanding the thermal conductivity of oxide superlattices.Peer reviewe

Structuring of di-alkyl-urethanesils

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Modeling the optical response of highly faceted metal nanoparticles with a fully 3D boundary element method

A study was conducted to develop a optical response model of highly faceted metal nanoparitcles by using a 3D boundary element method (BEM). The study also can be used to develop model for rod-to-octahedron transition. The BEM for axially symmetric particles can provide optical spectra in decorated nanorods, decahedrons, and nanostars. Gold nanorods were synthesized during the study in water and transfer into N,N-dimethylformamide (DMF). The study also examine the chemical growth of axially symmetric gold nanorods into octahedrons. It was observed during the study that the modeling of the cross-section is simple for a cylinder, while modeling of cross-section of prism require total width and the curvature of the edges. The study concluded that this method is computationally more efficient the DDA of FDTD techniques. © 2008This work was funded by the Spanish Ministerio de Educación y Ciencia, under contracts NAN2004-08843 and MAT2007-62696, and by the EU-FP6, under contract NMP4-2006-16881 ‘‘SPANS’’.Peer Reviewe

Synthetic strategy for metallophthalocyanine covalent organic frameworks for electrochemical water oxidation

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Synthetic strategy for metallophthalocyanine covalent organic frameworks for electrochemical water oxidation

International audienceAtomically dispersed metal catalysts are interesting materials for electrocatalysis. To this end, covalent organic frameworks (COFs) offer an excellent opportunity for the periodic placement of catalytically active single metal atoms within a porous framework. We report here a synthetic strategy to a series of imide-linked metal-containing phthalocyanine (Pc) COFs with different metal contents. Electrocatalytic activity of the materials towards oxygen evolution reaction was studied under alkaline conditions and the COF prepared from NiPc showed the best performance with current density j ¼ 10 mA cm À2 being reached at overpotential h 10 z 410 mV and Tafel slope of b ¼ 75 mV/dec. In addition, the material showed excellent long-term stability during the testing time of 100 h