The isolation of graphene and subsequent studies showed that obtaining atomically thin crystalline sheets was feasible and possessed extraordinary properties.This result opened the door to an entirely new family of ma...The isolation of graphene and subsequent studies showed that obtaining atomically thin crystalline sheets was feasible and possessed extraordinary properties.This result opened the door to an entirely new family of materials known as two-dimensional or 2D materials.Research in this field is intense:the emergence of new 2D materials,the properties of their combinations and the ability of graphene to reinvent itself,showing novel and exciting properties,make it likely that this field will continue to be one of the leading topics of materials science and condensed matter physics.展开更多
The complexation of high-spin lanthanides to porphyrinoids is a powerful strategy for the development of advanced molecular magnets.In this context,the use of expanded porphyrinoids remains elusive since their coordin...The complexation of high-spin lanthanides to porphyrinoids is a powerful strategy for the development of advanced molecular magnets.In this context,the use of expanded porphyrinoids remains elusive since their coordination chemistry is challenging to control.Herein,taking inspiration from on-surface chemistry,we explored the coordination of Dy^(3+)to a six-membered porphyrinoid,namely,the hemihexaphyrazine H3Hhp.Remarkably,we observed the selective formation of a mono-nuclear off-centered,out-of-plane H_(2)Hhp-Dy^(3+)complex when performing the complexation under reductive conditions.During this reaction,the oxidation state of the macrocycle did not change.Employing X-ray diffraction analysis,we found that the coordination number of Dy in this complex was 8.The macrocycle cocrystallized with decamethylcobaltocene(Cp_(2)^(*)Co)molecules,giving rise to a wellordered solid-state packing,governed byπ-πinteractions.As a result of this organization,a small magnetic coupling between the neighboring molecules was observed.All in all,this work provides key insights into the coordination of magnetically active metals with expanded porphyrinoids,thus motivating the development of advanced spintronic devices.展开更多
Scanning electrochemical microscopy represents a powerful tool for electro（chemical） characterization of surfaces, but its applicability has been limited in most cases at microscale spatial resolution, and the great...Scanning electrochemical microscopy represents a powerful tool for electro（chemical） characterization of surfaces, but its applicability has been limited in most cases at microscale spatial resolution, and the greatest challenge has been the scaling down to the nanoscale for fabrication and the use of nanometer-sized tips. Here, Pt nanoelectrodes with nanometer electroactive area were fabricated and employed for imaging a distribution of gold nanoparticles （AuNPs） and bioelectrocatalytic activity of a redox-active enzyme immobilized on gold surfaces.展开更多
A novel porous and crystalline two-dimensional(2D)electrochemically active covalent organic framework(COF)based on ortho-quinone units has been prepared as an innovative approach towards the development of organic cat...A novel porous and crystalline two-dimensional(2D)electrochemically active covalent organic framework(COF)based on ortho-quinone units has been prepared as an innovative approach towards the development of organic cathode materials with multiple redox sites as an efficient electrocatalyst for the oxygen reduction reaction(ORR).In contrast with most of the previously reported COFs as electrocatalysts for the ORR,the electrocatalytic application of this material towards ORR has been investigated without adding any metal or conductive supporting material and avoiding any additional carbonization step.Additionally,the electrochemical properties of the COF material have been compared with two analogue amorphous frameworks with similar chemical composition,which points out the important role of the enhanced crystallinity and porosity of the COF network in its superior performance as an electrocatalyst towards ORR.展开更多
Deposition of clean and defect-free atomically thin two-dimensional crystalline flakes on surfaces by mechanical exfoliation of layered bulk materials has proven to be a powerful technique, but it requires a fast, rel...Deposition of clean and defect-free atomically thin two-dimensional crystalline flakes on surfaces by mechanical exfoliation of layered bulk materials has proven to be a powerful technique, but it requires a fast, reliable and non-destructive way to identify the atomically thin flakes among a crowd of thick flakes. In this work, we provide general guidelines to identify ultrathin flakes of TaSe2 by means of optical microscopy and Raman spectroscopy. Additionally, we determine the optimal substrates to facilitate the optical identification of atomically thin TaSe2 crystals. Experimental realization and isolation of ultrathin layers of TaSe2 enables future studies on the role of the dimensionality in interesting phenomena such as superconductivity and charge density waves.展开更多
文摘The isolation of graphene and subsequent studies showed that obtaining atomically thin crystalline sheets was feasible and possessed extraordinary properties.This result opened the door to an entirely new family of materials known as two-dimensional or 2D materials.Research in this field is intense:the emergence of new 2D materials,the properties of their combinations and the ability of graphene to reinvent itself,showing novel and exciting properties,make it likely that this field will continue to be one of the leading topics of materials science and condensed matter physics.
基金financial support from the Russian Science Foundation (project N 21-13-00221)for the synthesis and studies of optical and magnetic properties of 1supported by the Ministry of Science and Higher Education of the Russian Federation (Registration number 124013100858-3)+2 种基金E.N.I.and M.K.I.acknowledge Grant from the Ministry of Science and Higher Education of the Russian Federation (no.075-15-2021-579)for synthesis of H3Hhp and preliminary DFT calculationssupport from the Spanish MCIN/AEI/10.13039/501100011033 (PID2020-116490GB-I00,TED2021-131255B-C43)the Comunidad de Madrid,and the Spanish State through the Recovery,Transformation and Resilience Plan[“Materiales Disruptivos Bidimensionales (2D)” (MAD2D-CM) (UAM1)-MRR Materiales Avanzados],and the European Union through the Next Generation EU funds.Instituto madrileno de estudios avanzados Nanociencia acknowledges support from the“Severo Ochoa”Programme for Centres of Excellence in R&D (Ministerio de asuntos economicos y transformacion digital,Grant SEV2016-0686).
文摘The complexation of high-spin lanthanides to porphyrinoids is a powerful strategy for the development of advanced molecular magnets.In this context,the use of expanded porphyrinoids remains elusive since their coordination chemistry is challenging to control.Herein,taking inspiration from on-surface chemistry,we explored the coordination of Dy^(3+)to a six-membered porphyrinoid,namely,the hemihexaphyrazine H3Hhp.Remarkably,we observed the selective formation of a mono-nuclear off-centered,out-of-plane H_(2)Hhp-Dy^(3+)complex when performing the complexation under reductive conditions.During this reaction,the oxidation state of the macrocycle did not change.Employing X-ray diffraction analysis,we found that the coordination number of Dy in this complex was 8.The macrocycle cocrystallized with decamethylcobaltocene(Cp_(2)^(*)Co)molecules,giving rise to a wellordered solid-state packing,governed byπ-πinteractions.As a result of this organization,a small magnetic coupling between the neighboring molecules was observed.All in all,this work provides key insights into the coordination of magnetically active metals with expanded porphyrinoids,thus motivating the development of advanced spintronic devices.
文摘Scanning electrochemical microscopy represents a powerful tool for electro（chemical） characterization of surfaces, but its applicability has been limited in most cases at microscale spatial resolution, and the greatest challenge has been the scaling down to the nanoscale for fabrication and the use of nanometer-sized tips. Here, Pt nanoelectrodes with nanometer electroactive area were fabricated and employed for imaging a distribution of gold nanoparticles （AuNPs） and bioelectrocatalytic activity of a redox-active enzyme immobilized on gold surfaces.
基金This work was financially supported by MICINN(Nos.PID2019-106268GB-C33,CTQ2017-84309-C2-1-R,RED2018-102412-T,and FIS2017-82415-R)Comunidad Autónoma de Madrid Transnanoavansens Program(No.S2018/NMT-4349)。
文摘A novel porous and crystalline two-dimensional(2D)electrochemically active covalent organic framework(COF)based on ortho-quinone units has been prepared as an innovative approach towards the development of organic cathode materials with multiple redox sites as an efficient electrocatalyst for the oxygen reduction reaction(ORR).In contrast with most of the previously reported COFs as electrocatalysts for the ORR,the electrocatalytic application of this material towards ORR has been investigated without adding any metal or conductive supporting material and avoiding any additional carbonization step.Additionally,the electrochemical properties of the COF material have been compared with two analogue amorphous frameworks with similar chemical composition,which points out the important role of the enhanced crystallinity and porosity of the COF network in its superior performance as an electrocatalyst towards ORR.
文摘Deposition of clean and defect-free atomically thin two-dimensional crystalline flakes on surfaces by mechanical exfoliation of layered bulk materials has proven to be a powerful technique, but it requires a fast, reliable and non-destructive way to identify the atomically thin flakes among a crowd of thick flakes. In this work, we provide general guidelines to identify ultrathin flakes of TaSe2 by means of optical microscopy and Raman spectroscopy. Additionally, we determine the optimal substrates to facilitate the optical identification of atomically thin TaSe2 crystals. Experimental realization and isolation of ultrathin layers of TaSe2 enables future studies on the role of the dimensionality in interesting phenomena such as superconductivity and charge density waves.
