Monodisperse sodium yttrium fluoride com sticks with hexagonal nanostructure were successfully prepared by a facile and repeatable precipitation transformation method. The phase and morphology of the products were cha...Monodisperse sodium yttrium fluoride com sticks with hexagonal nanostructure were successfully prepared by a facile and repeatable precipitation transformation method. The phase and morphology of the products were characterized with X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The growth mechanism was studied, indicating that the initial generated Y（OH）3 gradually translated into YF3 and then transformed into com stick-like H-NaYF4 nanoparticles owing to the crucial role of fluorine ions in the solution. The up-conversion （UC） luminescence properties of H-NaYF4：20%Yb3＋,2%Er3＋ nanocrystals were discussed. The intensive green emission in the range of 510-570 nm was attributed to the （2Hll/2, 4S3/2）----4It5/2 transition and the weaker red emission between 640 and 680 nm was originating from the 4F9/2----4115/2 transition.展开更多
The photonic characteristics of chromophore-containing metal-organic frameworks(MOFs)have led to extensive photophysical studies in an effort to capitalize on the potency of precisely controlled chromophore ensembles....The photonic characteristics of chromophore-containing metal-organic frameworks(MOFs)have led to extensive photophysical studies in an effort to capitalize on the potency of precisely controlled chromophore ensembles.Several examples have laid the foundation that demonstrates how photophysical properties of chromophores can be manipulated by tuning their communications(interactions)through integration within a MOF matrix.The main focus of this review is on harnessing the versatile MOF platform to accentuate the photophysical properties of integrated chromophores.In particular,this review will highlight chromophore dynamics that enhance,alter,or tune the photoluminescence response of single-and multi-chromophore-containing scaffolds,as well as alignment-guided anisotropic fluorescence.Building upon this groundwork,utilization of a hybrid crystalline motif can induce preferential orientation of chromophores resulting in enhanced communication and tailored behavior compared to randomly oriented emissive molecules.Moreover,frameworks that produce upconverted emission via sensitized triplet-triplet annihilation(sTTA),excited-state absorption(ESA),energy transfer upconversion(ETU),multi-photon absorption(MPA),or second-harmonic generation(SHG)can invoke dynamic control of material properties using photochromic linkers and will be discussed herein with a focus on the effects of chromophore alignment.Integration within a framework is a vehicle tofuse chromophores into solid-state platforms,opening an avenue for chromophore utilization in applications such as portable electronics that require solids or thin films.For those reasons,the design of chromophore-containing MOFs with desirable properties that rely on the alignment and communication of hundreds of chromophores within a single platform is a pressing demand for the development of futuristic technologies.展开更多
基金supported by the National Natural Science Foundation(NSF)of China(51202066)Program for New Century Excellent Talents supported by the China Education Ministry(NCET-13-0784)+5 种基金Study Abroad Program sponsored by China Scholarship Council(201308430385)Scientific Research Fund of Hunan Provincial Education Department(12A047)Research of Science and Technology Department of Hunan Province(2013SK3162)State Key Laboratory Program of Rare Earth Resource Utilization of China(RERU2013019)State Key Laboratory Programs of Inorganic Synthesis and Preparative Chemistry of China(2013-26)Key Laboratory Program of Ecological Impacts of Hydraulic-projects and Restoration of Aquatic Ecosystem in Ministry of Water Resources of China(2013001)
文摘Monodisperse sodium yttrium fluoride com sticks with hexagonal nanostructure were successfully prepared by a facile and repeatable precipitation transformation method. The phase and morphology of the products were characterized with X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The growth mechanism was studied, indicating that the initial generated Y（OH）3 gradually translated into YF3 and then transformed into com stick-like H-NaYF4 nanoparticles owing to the crucial role of fluorine ions in the solution. The up-conversion （UC） luminescence properties of H-NaYF4：20%Yb3＋,2%Er3＋ nanocrystals were discussed. The intensive green emission in the range of 510-570 nm was attributed to the （2Hll/2, 4S3/2）----4It5/2 transition and the weaker red emission between 640 and 680 nm was originating from the 4F9/2----4115/2 transition.
基金the NSF CAREER Award(DM R-1553634)a Cottrell Scholar Award from the Research Corporation for Science Advancement.N.B.S.also acknowledges support from the Sloan Research Fellowship provided by the Alfred P.Sloan Foundation and the Dreyfus Teaching-Scholar Award supported by the Dreyflis Foundation.
文摘The photonic characteristics of chromophore-containing metal-organic frameworks(MOFs)have led to extensive photophysical studies in an effort to capitalize on the potency of precisely controlled chromophore ensembles.Several examples have laid the foundation that demonstrates how photophysical properties of chromophores can be manipulated by tuning their communications(interactions)through integration within a MOF matrix.The main focus of this review is on harnessing the versatile MOF platform to accentuate the photophysical properties of integrated chromophores.In particular,this review will highlight chromophore dynamics that enhance,alter,or tune the photoluminescence response of single-and multi-chromophore-containing scaffolds,as well as alignment-guided anisotropic fluorescence.Building upon this groundwork,utilization of a hybrid crystalline motif can induce preferential orientation of chromophores resulting in enhanced communication and tailored behavior compared to randomly oriented emissive molecules.Moreover,frameworks that produce upconverted emission via sensitized triplet-triplet annihilation(sTTA),excited-state absorption(ESA),energy transfer upconversion(ETU),multi-photon absorption(MPA),or second-harmonic generation(SHG)can invoke dynamic control of material properties using photochromic linkers and will be discussed herein with a focus on the effects of chromophore alignment.Integration within a framework is a vehicle tofuse chromophores into solid-state platforms,opening an avenue for chromophore utilization in applications such as portable electronics that require solids or thin films.For those reasons,the design of chromophore-containing MOFs with desirable properties that rely on the alignment and communication of hundreds of chromophores within a single platform is a pressing demand for the development of futuristic technologies.
