The application of emerging luminophores such as near-infrared(NIR)emissive complexes based on earth-abundant chromium as central ion and triplet-triplet annihilation upconversion(TTA-UC)systems in air as optical repo...The application of emerging luminophores such as near-infrared(NIR)emissive complexes based on earth-abundant chromium as central ion and triplet-triplet annihilation upconversion(TTA-UC)systems in air as optical reporters for bioimaging or photonic materials for energy conversion requires simple and efficient strategies for their complete protection from luminescence quenching by oxygen.Therefore,we explored the influence of sol-gel synthesis routes on the oxygen protection efficiency of the resulting core and core/shell silica nanoparticles(SiO_(2)NPs),utilizing the molecular ruby-type luminophores CrPF_(6)([Cr(ddpd)_(2)](PF_(6))_(3);ddpd=N,N′-dimethyl-N,N′-dipyridin-2-ylpyridin-2,6-diamine)and CrBF_(4)([Cr(ddpd)_(2)](BF_(4))_(3))with their oxygen-dependent,but polarity-,proticity-,viscosity-,and concentration-independent luminescence as optical probes for oxygen permeability.The sol-gel chemistry routes we assessed include the classical Stöber method and the underexplored L-arginine approach,which relies on the controlled hydrolysis of tetraethoxysilane(TEOS)in a biphasic cyclohexane/water system with the catalyst L-arginine.As demonstrated by luminescence measurements of air-and argon-saturated dispersions of CrPF_(6)-and CrBF_(4)-stained SiO_(2)NPs of different size and particle architecture,utilizing the luminescence decay kinetics of argon-saturated solutions of CrPF_(6)and CrBF_(4)in acetonitrile(ACN)as benchmarks,only SiO_(2)NPs or shells synthesized by the L-arginine approach provided complete oxygen protection of the CrⅢcomplexes under ambient conditions.We ascribe the different oxygen shielding efficiencies of the silica networks explored to differences in density and surface chemistry of the resulting nanomaterials and coatings,leading to different oxygen permeabilities.Our L-arginine based silica encapsulation strategy can open the door for the efficient usage of oxygen-sensitive luminophores and TTA-UC systems as optical reporters and spectral shifters in air in the future.展开更多
The oxygen quenching effect in a Linear Alkl Benzene （LAB） based liquid scintillator （LAB as the solvent, 3 g/L 2, 5 diphe-nyloxazole （PPO） as the fluor and 15 mg/L p-bis-（o-methylstyryl）-benzene （bis-MSB） as...The oxygen quenching effect in a Linear Alkl Benzene （LAB） based liquid scintillator （LAB as the solvent, 3 g/L 2, 5 diphe-nyloxazole （PPO） as the fluor and 15 mg/L p-bis-（o-methylstyryl）-benzene （bis-MSB） as the h-shifter） is studied by measuring the light yield as a function of the nitrogen bubbling time. It is shown that the light yield of the fully purged liquid scintillator is increased by 11% at room temperature and the room atmospheric pressure. A simple nitrogen bubbling model is proposed to describe the relationship between the relative light yield （oxygen quenching factor） and the bubbling time.展开更多
28 kinds of carotenoids are studied to reveal the key parameters and regulation on the singlet oxygen quenching rate.First,the quantum chemistry parameters of carotenoids calculated by Gaussian software combined with ...28 kinds of carotenoids are studied to reveal the key parameters and regulation on the singlet oxygen quenching rate.First,the quantum chemistry parameters of carotenoids calculated by Gaussian software combined with substitution parameters were used to construct the quantitative structure-activity relationship model(QSAR)of the singlet oxygen quenching rate of carotenoids.The key parameters affecting the antioxidant activity of carotenoids are revealed,and the data predicted via the QSAR model were provided for subsequent research.Then,a three-dimensional(3D)pharmacophore model was used to regulate and modify the antioxidant activity of carotenoids.The correlation coefficients of the modeling group(R2)and verification group(Rpre2)of the established QSAR model were 0.945 and 0.916,respectively,which can be used for the analysis of antioxidant activity of carotenoids;the antioxidant activity of carotenoids can be significantly regulated by the number of conjugated C=C bonds,the energy difference between frontier molecular orbitals and the partial Mulliken charge in C1 and theπ···π*excitation energy E(s);the antioxidant activity of carotenoids can be effectively regulated by the hydrogen bond acceptor pharmacophores on both sides of the conjugated C=C bonds and the hydrophobic groups on the conjugated C=C bond;the hydrophobic substituents attached to conjugated C=C bonds can effectively improve the singlet oxygen quenching rate of carotenoids.展开更多
We report a reproducible approach in preparing high-quality overdoped Bi2 Sr2 CaCu2 08＋δ （Bi2212） single crystals by annealing Bi2212 crystals in high oxygen pressure followed by a fast quenching. In this way, hig...We report a reproducible approach in preparing high-quality overdoped Bi2 Sr2 CaCu2 08＋δ （Bi2212） single crystals by annealing Bi2212 crystals in high oxygen pressure followed by a fast quenching. In this way, high-quality overdoped and heavily overdoped Bi2212 single crystals are obtained by controlling the annealing oxygen pressure. We find that, beyond a limit of oxygen pressure that can achieve most heavily overdoped Bi2212 with a Tc N63 K, the annealed Bi2212 begins to decompose. This accounts for the existence of the hole-doping limit and thus the Tc limit in the heavily overdoped region of Bi2212 by the oxygen annealing process. These results provide a reliable way in preparing high-quality overdoped and heavily overdoped Bi2212 crystals that are important for studies of the physical properties, electronic structure and superconductivity mechanism of the cuprate superconductors.展开更多
基金supported by the Scientific Service Units of IST Austria through resources provided by the Electron Microscopy FacilityThe authors gratefully acknowledge financial support by the projects AquaFunkNano(Federal Ministry for Economic Affairs and Climate Action(BmWK,program WIPANO))+1 种基金MiGraGen(Novo Nordisk Fonden,Interdisciplinary Synergy Program 2021),grant No.P-34662 from the Austrian Science Foundation(M.R.R.)the DFG project NILECHROME 2.0(grants RE 1203/23-2 and HE 2778/10-2).
文摘The application of emerging luminophores such as near-infrared(NIR)emissive complexes based on earth-abundant chromium as central ion and triplet-triplet annihilation upconversion(TTA-UC)systems in air as optical reporters for bioimaging or photonic materials for energy conversion requires simple and efficient strategies for their complete protection from luminescence quenching by oxygen.Therefore,we explored the influence of sol-gel synthesis routes on the oxygen protection efficiency of the resulting core and core/shell silica nanoparticles(SiO_(2)NPs),utilizing the molecular ruby-type luminophores CrPF_(6)([Cr(ddpd)_(2)](PF_(6))_(3);ddpd=N,N′-dimethyl-N,N′-dipyridin-2-ylpyridin-2,6-diamine)and CrBF_(4)([Cr(ddpd)_(2)](BF_(4))_(3))with their oxygen-dependent,but polarity-,proticity-,viscosity-,and concentration-independent luminescence as optical probes for oxygen permeability.The sol-gel chemistry routes we assessed include the classical Stöber method and the underexplored L-arginine approach,which relies on the controlled hydrolysis of tetraethoxysilane(TEOS)in a biphasic cyclohexane/water system with the catalyst L-arginine.As demonstrated by luminescence measurements of air-and argon-saturated dispersions of CrPF_(6)-and CrBF_(4)-stained SiO_(2)NPs of different size and particle architecture,utilizing the luminescence decay kinetics of argon-saturated solutions of CrPF_(6)and CrBF_(4)in acetonitrile(ACN)as benchmarks,only SiO_(2)NPs or shells synthesized by the L-arginine approach provided complete oxygen protection of the CrⅢcomplexes under ambient conditions.We ascribe the different oxygen shielding efficiencies of the silica networks explored to differences in density and surface chemistry of the resulting nanomaterials and coatings,leading to different oxygen permeabilities.Our L-arginine based silica encapsulation strategy can open the door for the efficient usage of oxygen-sensitive luminophores and TTA-UC systems as optical reporters and spectral shifters in air in the future.
基金Supported by Nation Natural Science Foundation of China (211202037)
文摘The oxygen quenching effect in a Linear Alkl Benzene （LAB） based liquid scintillator （LAB as the solvent, 3 g/L 2, 5 diphe-nyloxazole （PPO） as the fluor and 15 mg/L p-bis-（o-methylstyryl）-benzene （bis-MSB） as the h-shifter） is studied by measuring the light yield as a function of the nitrogen bubbling time. It is shown that the light yield of the fully purged liquid scintillator is increased by 11% at room temperature and the room atmospheric pressure. A simple nitrogen bubbling model is proposed to describe the relationship between the relative light yield （oxygen quenching factor） and the bubbling time.
文摘28 kinds of carotenoids are studied to reveal the key parameters and regulation on the singlet oxygen quenching rate.First,the quantum chemistry parameters of carotenoids calculated by Gaussian software combined with substitution parameters were used to construct the quantitative structure-activity relationship model(QSAR)of the singlet oxygen quenching rate of carotenoids.The key parameters affecting the antioxidant activity of carotenoids are revealed,and the data predicted via the QSAR model were provided for subsequent research.Then,a three-dimensional(3D)pharmacophore model was used to regulate and modify the antioxidant activity of carotenoids.The correlation coefficients of the modeling group(R2)and verification group(Rpre2)of the established QSAR model were 0.945 and 0.916,respectively,which can be used for the analysis of antioxidant activity of carotenoids;the antioxidant activity of carotenoids can be significantly regulated by the number of conjugated C=C bonds,the energy difference between frontier molecular orbitals and the partial Mulliken charge in C1 and theπ···π*excitation energy E(s);the antioxidant activity of carotenoids can be effectively regulated by the hydrogen bond acceptor pharmacophores on both sides of the conjugated C=C bonds and the hydrophobic groups on the conjugated C=C bond;the hydrophobic substituents attached to conjugated C=C bonds can effectively improve the singlet oxygen quenching rate of carotenoids.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11190022,11334010 and 11534007the National Basic Research Program of China under Grant No 2015CB921000the Strategic Priority Research Program(B)of Chinese Academy of Sciences under Grant No XDB07020300
文摘We report a reproducible approach in preparing high-quality overdoped Bi2 Sr2 CaCu2 08＋δ （Bi2212） single crystals by annealing Bi2212 crystals in high oxygen pressure followed by a fast quenching. In this way, high-quality overdoped and heavily overdoped Bi2212 single crystals are obtained by controlling the annealing oxygen pressure. We find that, beyond a limit of oxygen pressure that can achieve most heavily overdoped Bi2212 with a Tc N63 K, the annealed Bi2212 begins to decompose. This accounts for the existence of the hole-doping limit and thus the Tc limit in the heavily overdoped region of Bi2212 by the oxygen annealing process. These results provide a reliable way in preparing high-quality overdoped and heavily overdoped Bi2212 crystals that are important for studies of the physical properties, electronic structure and superconductivity mechanism of the cuprate superconductors.
