Ultrasmall(10.8 nm)and uniform hexagonal NaYF_(4):Yb^(3+),Er^(3+)upconversion nanocrystals have been successfully synthesized through a temperature oscillation technique,and the nucleation and growth processes of nano...Ultrasmall(10.8 nm)and uniform hexagonal NaYF_(4):Yb^(3+),Er^(3+)upconversion nanocrystals have been successfully synthesized through a temperature oscillation technique,and the nucleation and growth processes of nanocrystals were effectively separated and controlled by simply regulating the heating procedures.展开更多
Polymorphism is crucial for unraveling crystallization mechanisms,predicting crystal structures and discovering novel materials.A new high-symmetry polymorph of Li_(2)TeMo_(3)O_(12),β-Li_(2)TeMo_(3)O_(12),was identif...Polymorphism is crucial for unraveling crystallization mechanisms,predicting crystal structures and discovering novel materials.A new high-symmetry polymorph of Li_(2)TeMo_(3)O_(12),β-Li_(2)TeMo_(3)O_(12),was identified successfully by a spontaneous crystallization technique,and it exhibits improved thermal stability and crystallizes in the trigonal space group R3(No.148)in contrast to the metastable α-Li_(2)TeMo_(3)O_(12).Thermal analysis and variable-temperature X-ray diffraction powder patterns demonstrated an irreversible phase transition of Li_(2)TeMo_(3)O_(12)from α-Li_(2)TeMo_(3)O_(12)to β-Li_(2)TeMo_(3)O_(12).High-quality and centimetre-sized single crystals of β-Li_(2)TeMo_(3)O_(12)were extracted via a facile flux approach.Moreover,optical characterization showed that it has a large bandgap of 3.05 eV accompanied by high transparency from 0.34 to 5.4μm,encompassing a 3-5μm atmospheric window.Remarkably,the title compound features the intriguing merits of an intrinsically strong Raman shift located at 955 cm^(−1) and a narrow line width of 12.54 cm^(−1),which enable it to act as a stimulated Raman laser,making it a promising mid-infrared Raman crystal.Additionally,theoretical investigations are used to evaluate the fundamental relationships between the compound’s structure and optical properties.展开更多
基金the financial support from the National Key Basic Research Program of China(973 Program,2014CB648300)the National Natural Science Foundation of China(21422402,21674050,and 61136003)+10 种基金the Natural Science Foundation of Jiangsu Province(BK20160073,BK20140060,BK20130037,and BM2012010)the Program for Jiangsu Specially-Appointed Professors(RK030STP15001)the Program for New Century Excellent Talents in University(NCET-13-0872)the Specialized Research Fund for the Doctoral Program of Higher Education(20133223110008)the Synergetic Innovation Center for Organic Electronics and Information Displaysthe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the NUPT“1311 Project”the Six Talent Plan(2012XCL035)the 333 Project(BRA2015374)the Qing Lan Project of Jiangsu Provincesponsored by NUPTSF(NY216025 and NY217073).
文摘Ultrasmall(10.8 nm)and uniform hexagonal NaYF_(4):Yb^(3+),Er^(3+)upconversion nanocrystals have been successfully synthesized through a temperature oscillation technique,and the nucleation and growth processes of nanocrystals were effectively separated and controlled by simply regulating the heating procedures.
基金financially supported by the National Natural Science Foundation of China(Grant No.52002273,51972229,61835014 and 51890864)National Key R&D Program of China(2021YFA0717800).
文摘Polymorphism is crucial for unraveling crystallization mechanisms,predicting crystal structures and discovering novel materials.A new high-symmetry polymorph of Li_(2)TeMo_(3)O_(12),β-Li_(2)TeMo_(3)O_(12),was identified successfully by a spontaneous crystallization technique,and it exhibits improved thermal stability and crystallizes in the trigonal space group R3(No.148)in contrast to the metastable α-Li_(2)TeMo_(3)O_(12).Thermal analysis and variable-temperature X-ray diffraction powder patterns demonstrated an irreversible phase transition of Li_(2)TeMo_(3)O_(12)from α-Li_(2)TeMo_(3)O_(12)to β-Li_(2)TeMo_(3)O_(12).High-quality and centimetre-sized single crystals of β-Li_(2)TeMo_(3)O_(12)were extracted via a facile flux approach.Moreover,optical characterization showed that it has a large bandgap of 3.05 eV accompanied by high transparency from 0.34 to 5.4μm,encompassing a 3-5μm atmospheric window.Remarkably,the title compound features the intriguing merits of an intrinsically strong Raman shift located at 955 cm^(−1) and a narrow line width of 12.54 cm^(−1),which enable it to act as a stimulated Raman laser,making it a promising mid-infrared Raman crystal.Additionally,theoretical investigations are used to evaluate the fundamental relationships between the compound’s structure and optical properties.
