Two-dimensional(2D)nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity;however,their synthesis remains challenging.Research has relied on traditional molten salt etching,highlight...Two-dimensional(2D)nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity;however,their synthesis remains challenging.Research has relied on traditional molten salt etching,highlighting the need for a scalable,high-purity approach.Here,we present the first solution-based synthesis of Ti_(4)N_(3)T_(x)MXene via a novel saturated salt solution(S^(3))etching technique employing alkali metal salts.By optimizing the sintering process for high-purity Ti_(4)AlN_(3)MAX and refining the S^(3)etching route,we significantly reduced the etch pit density to 1.2×10^(6)cm^(-2)and lowered the etch pit formation rate to 4%,yielding high-quality,phasepure Ti_(4)N_(3)T_(x)MXene.Our study highlights the critical role of alkali metal ions in selective A-layer removal and demonstrates the impressive electrical conductivity and electromagnetic interference shielding performance of 2D nitride MXene,setting a new benchmark for this underexplored material.These findings pave the way for advancing 2D nitride MXenes and their diverse applications.展开更多
Understanding the precise molecular arrangement of chiral supramolecular polymers is essential not only to comprehend complex superstructures like proteins and DNA but also for the development of next-generation optoe...Understanding the precise molecular arrangement of chiral supramolecular polymers is essential not only to comprehend complex superstructures like proteins and DNA but also for the development of next-generation optoelectronic materials,including materials displaying high-performance circularly polarized luminescence(CPL).Herein,we report the first chiral supramolecular polymer systems based on hydrazone–pyridinium conjugates comprising alkyl chains of different lengths,which afforded control of the apparent supramolecular chirality.Although supramolecular chirality is governed basically by the remote chiral centers of alkyl chains,helicity inversion was achieved by controlling the conditions under which the hydrazone building blocks underwent aggregation(i.e.,solvent compositions or temperature).More importantly,the addition of water to the system led to aggregationinduced hydrazone deprotonation,which resulted in a completely different selfassembly behavior.Structural water molecules played an essential role,forming the assembly’s channel-like backbone,around which hydrazone molecules gathered as a result of hydrogen bonding interactions.Further co-assembly of an achiral hydrazone luminophore with the given supramolecular polymer system allowed the fabrication of a novel CPL-active hydrazone-based material exhibiting a high maximum value for the photoluminescence dissymmetry factor of -2.6×10^(-2).展开更多
基金supported by the Nano&Material Technology Development Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(Grant No.RS-2024-00408180)by Institute for Basic Science(No.IBS-R019-G1).
文摘Two-dimensional(2D)nitride MXenes are predicted to exhibit exceptional metallic properties and high polarity;however,their synthesis remains challenging.Research has relied on traditional molten salt etching,highlighting the need for a scalable,high-purity approach.Here,we present the first solution-based synthesis of Ti_(4)N_(3)T_(x)MXene via a novel saturated salt solution(S^(3))etching technique employing alkali metal salts.By optimizing the sintering process for high-purity Ti_(4)AlN_(3)MAX and refining the S^(3)etching route,we significantly reduced the etch pit density to 1.2×10^(6)cm^(-2)and lowered the etch pit formation rate to 4%,yielding high-quality,phasepure Ti_(4)N_(3)T_(x)MXene.Our study highlights the critical role of alkali metal ions in selective A-layer removal and demonstrates the impressive electrical conductivity and electromagnetic interference shielding performance of 2D nitride MXene,setting a new benchmark for this underexplored material.These findings pave the way for advancing 2D nitride MXenes and their diverse applications.
基金National Research Foundation of Korea,Grant/Award Number:2012M3A7B4049677Nano Material Development Program,Grant/Award Number:2020R1A6A3A01100092+1 种基金Basic ScienceResearch ProgramInstitute forBasic Science,Grant/Award Number:IBS-R019-D1。
文摘Understanding the precise molecular arrangement of chiral supramolecular polymers is essential not only to comprehend complex superstructures like proteins and DNA but also for the development of next-generation optoelectronic materials,including materials displaying high-performance circularly polarized luminescence(CPL).Herein,we report the first chiral supramolecular polymer systems based on hydrazone–pyridinium conjugates comprising alkyl chains of different lengths,which afforded control of the apparent supramolecular chirality.Although supramolecular chirality is governed basically by the remote chiral centers of alkyl chains,helicity inversion was achieved by controlling the conditions under which the hydrazone building blocks underwent aggregation(i.e.,solvent compositions or temperature).More importantly,the addition of water to the system led to aggregationinduced hydrazone deprotonation,which resulted in a completely different selfassembly behavior.Structural water molecules played an essential role,forming the assembly’s channel-like backbone,around which hydrazone molecules gathered as a result of hydrogen bonding interactions.Further co-assembly of an achiral hydrazone luminophore with the given supramolecular polymer system allowed the fabrication of a novel CPL-active hydrazone-based material exhibiting a high maximum value for the photoluminescence dissymmetry factor of -2.6×10^(-2).
