Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights （up to 1 × 10^6） in high yields （up to 99.9%）. The polym...Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights （up to 1 × 10^6） in high yields （up to 99.9%）. The polymers possess low intrinsic viscosities and high thermal stabilities, losing little of their weights when heated to 〉 400℃. Upon pyrolysis at 〉 800℃, the polymers graphitize with high char yields （up to 86%）. Hyperbranched polyarylenes efficiently emit deep-blue to blue-green lights with fluorescence quantum yields up to 98% and strongly attenuate intense laser pulses with optical power-limiting performances superior to that of C60, a well-known optical limiter. Poly（alkenephenylenes）, poly（aroylarylenes） and polyynes are readily cross-linkable by UV irradiation, serving as excellent photoresist materials for the generation of patterns with nanometer resolution. Thin films of hyperbranched polyynes exhibit very high refractive indexes （n up to 1.86）. The internal and terminal acetylene moieties of the polyynes readily form complexes with cobalt carbonyls, which can be transformed into soft ferromagnetic ceramics with high magnetic susceptibilities （Ms up to ca. 118 emu/g） and near-zero magnetic losses.展开更多
Both the cluster chemistry of tin and lanthanides have attracted extensive research interest,showing wide applications in catalysis,magnetism,luminescence,and lithography.However,their fusion into heterometallic Sn-Ln...Both the cluster chemistry of tin and lanthanides have attracted extensive research interest,showing wide applications in catalysis,magnetism,luminescence,and lithography.However,their fusion into heterometallic Sn-Ln oxo clusters is still to be explored.In this study,through the stabilization of alkenyl-type cis-5-norbornene-endo-2,3-dicarboxylic acid(H_(2)NE)ligands,a series of atomically precise Sn-Ln oxo nanoclusters have been successfully constructed from the assembly of heterometallic tetranuclear Sn_(x)Ln((4-x))building blocks.Thereinto,Sn_(12)Eu_(8) and Sn_(13)Er_(6) with the highest nuclearities are built from multiple assembly of 8{Sn_(2)Eu_(2)}units and 6{Sn_(3)Er}and{Sn_(2)Er_(2)}units,respectively.ESI-MS analysis indicates that Sn_(13)Er_(6) has high solution stability,allowing their packing into thin films for lithography applications.As a result of electron beam lithography(EBL)studies,the condensation of Sn_(13)Er_(6) can be triggered by low energy radiation of 10μC/cm^(2),and 50 nm lines have been fabricated at expose energy of 50μC/cm^(2),confirming the satisfying sensitivity and resolution of Sn_(13)Er_(6).Hence,the success of this study develops the chemistry of heterometallic tin-lanthanide clusters that can be applied as novel negative photoresist materials.展开更多
The copolymers of chloroethyl methacrylate (CMA), glycidyl methacrylate (GMA), and methyl methacrylate (MMA) were synthesized in benzene solution. Their breadths of the molecular weight distributions are 2.1 and 2.3,...The copolymers of chloroethyl methacrylate (CMA), glycidyl methacrylate (GMA), and methyl methacrylate (MMA) were synthesized in benzene solution. Their breadths of the molecular weight distributions are 2.1 and 2.3, respectively. The thermal stability of P(GMA-CMA) is superior to that of P(CMA-MMA). The resolutions of P(CMA-MMA) and P(GMA-CMA) photoresists were found to be 0.1-0.16 mu m and 0.17-0.2 mu m, respectively. (Author abstract) 9 Refs.展开更多
As a component of near-field scanning optical microscope （NSOM）, optical fiber probe is an important factor influncing the equipment resolution. Electroless nickel plating is introduced to metallize the optical fibe...As a component of near-field scanning optical microscope （NSOM）, optical fiber probe is an important factor influncing the equipment resolution. Electroless nickel plating is introduced to metallize the optical fiber probe. The optical fibers are etched by 40% HF with Turner etching method. Through pretreatment, the optical fiber probe is coated with Ni-P film by electroless plating in a constant temperature water tank. Atomic absorption spectrometry （AAS）, scanning electron microscopy （SEM）, and energy dispersive X-ray spectrometry （EDXS） are carried out to characterize the deposition on fiber probe. We have reproducibly fabricated two kinds of fiber probes with a Ni-P film： aperture probe and apertureless probe. In addition, reductive particle transportation on the surface of fiber probe is proposed to explain the cause of these probes.展开更多
基金This work was partially supported by the Hong Kong Research Grants Council,the University Grants Committee of Hong Kong,and the National Natural Science Foundation of China.
文摘Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights （up to 1 × 10^6） in high yields （up to 99.9%）. The polymers possess low intrinsic viscosities and high thermal stabilities, losing little of their weights when heated to 〉 400℃. Upon pyrolysis at 〉 800℃, the polymers graphitize with high char yields （up to 86%）. Hyperbranched polyarylenes efficiently emit deep-blue to blue-green lights with fluorescence quantum yields up to 98% and strongly attenuate intense laser pulses with optical power-limiting performances superior to that of C60, a well-known optical limiter. Poly（alkenephenylenes）, poly（aroylarylenes） and polyynes are readily cross-linkable by UV irradiation, serving as excellent photoresist materials for the generation of patterns with nanometer resolution. Thin films of hyperbranched polyynes exhibit very high refractive indexes （n up to 1.86）. The internal and terminal acetylene moieties of the polyynes readily form complexes with cobalt carbonyls, which can be transformed into soft ferromagnetic ceramics with high magnetic susceptibilities （Ms up to ca. 118 emu/g） and near-zero magnetic losses.
基金supported by the National Natural Science Foundation of China(21922111,91961108,21935010,22271284)。
文摘Both the cluster chemistry of tin and lanthanides have attracted extensive research interest,showing wide applications in catalysis,magnetism,luminescence,and lithography.However,their fusion into heterometallic Sn-Ln oxo clusters is still to be explored.In this study,through the stabilization of alkenyl-type cis-5-norbornene-endo-2,3-dicarboxylic acid(H_(2)NE)ligands,a series of atomically precise Sn-Ln oxo nanoclusters have been successfully constructed from the assembly of heterometallic tetranuclear Sn_(x)Ln((4-x))building blocks.Thereinto,Sn_(12)Eu_(8) and Sn_(13)Er_(6) with the highest nuclearities are built from multiple assembly of 8{Sn_(2)Eu_(2)}units and 6{Sn_(3)Er}and{Sn_(2)Er_(2)}units,respectively.ESI-MS analysis indicates that Sn_(13)Er_(6) has high solution stability,allowing their packing into thin films for lithography applications.As a result of electron beam lithography(EBL)studies,the condensation of Sn_(13)Er_(6) can be triggered by low energy radiation of 10μC/cm^(2),and 50 nm lines have been fabricated at expose energy of 50μC/cm^(2),confirming the satisfying sensitivity and resolution of Sn_(13)Er_(6).Hence,the success of this study develops the chemistry of heterometallic tin-lanthanide clusters that can be applied as novel negative photoresist materials.
基金This work is financially supported by the National Natural Science Foundation of China.
文摘The copolymers of chloroethyl methacrylate (CMA), glycidyl methacrylate (GMA), and methyl methacrylate (MMA) were synthesized in benzene solution. Their breadths of the molecular weight distributions are 2.1 and 2.3, respectively. The thermal stability of P(GMA-CMA) is superior to that of P(CMA-MMA). The resolutions of P(CMA-MMA) and P(GMA-CMA) photoresists were found to be 0.1-0.16 mu m and 0.17-0.2 mu m, respectively. (Author abstract) 9 Refs.
基金supported by the National "973" Program of China (No.2009CB930604)the Natural Science Foundation of Guangdong Province,China (No.8151064101000111)
文摘As a component of near-field scanning optical microscope （NSOM）, optical fiber probe is an important factor influncing the equipment resolution. Electroless nickel plating is introduced to metallize the optical fiber probe. The optical fibers are etched by 40% HF with Turner etching method. Through pretreatment, the optical fiber probe is coated with Ni-P film by electroless plating in a constant temperature water tank. Atomic absorption spectrometry （AAS）, scanning electron microscopy （SEM）, and energy dispersive X-ray spectrometry （EDXS） are carried out to characterize the deposition on fiber probe. We have reproducibly fabricated two kinds of fiber probes with a Ni-P film： aperture probe and apertureless probe. In addition, reductive particle transportation on the surface of fiber probe is proposed to explain the cause of these probes.
