Ratiometric fluorescent detection of iron(Ⅲ)(Fe^(3+))offers inherent self-calibration and contactless analytic capabilities.However,realizing a dual-emission near-infrared(NIR)nanosensor with a low limit of detection...Ratiometric fluorescent detection of iron(Ⅲ)(Fe^(3+))offers inherent self-calibration and contactless analytic capabilities.However,realizing a dual-emission near-infrared(NIR)nanosensor with a low limit of detection(LOD)is rather challenging.In this work,we report the synthesis of water-dispersible erbium-hyperdoped silicon quantum dots(Si QDs:Er),which emit NIR light at the wavelengths of 810 and 1540 nm.A dual-emission NIR nanosensor based on water-dispersible Si QDs:Er enables ratiometric Fe^(3+)detection with a very low LOD(0.06μM).The effects of pH,recyclability,and the interplay between static and dynamic quenching mechanisms for Fe^(3+)detection have been systematically studied.In addition,we demonstrate that the nanosensor may be used to construct a sequential logic circuit with memory functions.展开更多
Surface modification may be an effective means for controlling the properties of germanane, i.e., hydrogenated germanene. In this work, we investigate the formation, stability, structure and electronic properties of s...Surface modification may be an effective means for controlling the properties of germanane, i.e., hydrogenated germanene. In this work, we investigate the formation, stability, structure and electronic properties of surface-modified germanane that results from the hydrogermylation, alkoxylation, aminization or phenylation of germanane. By assuming the typical organic surface coverage of -33%, we have com- pared organically surface-modified germanane with germanene and germanane in the framework of density functional theory. It is found that organically surface-modified germanane may all stably exist despite the endothermic nature of organic surface modification. Organic surface modification leads to the de- crease of the Ge--Ge bond length and the Ge--Ge-Ge bond angle ofgermanane, while causing the buckling distance of germanane to increase. Hydrogenation makes germanene change from a semimetal to a direct- bandgap semiconductor. Organic surface modification further impacts the band structure of the resulting germanane. Hydrogermylated/alkoxylated germanane is a direct-bandgap semiconductor, while aminated/ phenylated germanane is an indirect-bandgap semiconductor. All the organic surface modification gives rise to the increase of the bandgap of germanane.展开更多
The formation, structural and electronic properties of silicene oxides（SOs） that result from the oxidation of silicene on Ag（111） surface have been investigated in the framework of density functional theory（DFT）...The formation, structural and electronic properties of silicene oxides（SOs） that result from the oxidation of silicene on Ag（111） surface have been investigated in the framework of density functional theory（DFT）.It is found that the honeycomb lattice of silicene on the Ag（111） surface changes after the oxidation. SOs are strongly hybridized with the Ag（111） surface so that they possess metallic band structures. Charge accumulation between SOs and the Ag（111） surface indicates strong chemical bonding, which dramatically affects the electronic properties of SOs. When SOs are peeled off the Ag（111） surface, however, they may become semiconductors.展开更多
基金supported by the National Natural Science Foundation of China(U22A2075,U20A20209)the Fundamental Research Funds for the Central Universities(226-2022-00200)the Qianjiang Distinguished Experts program of Hangzhou.
文摘Ratiometric fluorescent detection of iron(Ⅲ)(Fe^(3+))offers inherent self-calibration and contactless analytic capabilities.However,realizing a dual-emission near-infrared(NIR)nanosensor with a low limit of detection(LOD)is rather challenging.In this work,we report the synthesis of water-dispersible erbium-hyperdoped silicon quantum dots(Si QDs:Er),which emit NIR light at the wavelengths of 810 and 1540 nm.A dual-emission NIR nanosensor based on water-dispersible Si QDs:Er enables ratiometric Fe^(3+)detection with a very low LOD(0.06μM).The effects of pH,recyclability,and the interplay between static and dynamic quenching mechanisms for Fe^(3+)detection have been systematically studied.In addition,we demonstrate that the nanosensor may be used to construct a sequential logic circuit with memory functions.
基金mainly supported by the National Basic Research Program of China(973 program,Grant No.2013CB632101)the National Natural Science Foundation of China(Grant Nos.61222404 and 61474097)Partial support is provided by the Fundamental Research Funds for Central Universities(Grant No.2014XZZX003-09)
文摘Surface modification may be an effective means for controlling the properties of germanane, i.e., hydrogenated germanene. In this work, we investigate the formation, stability, structure and electronic properties of surface-modified germanane that results from the hydrogermylation, alkoxylation, aminization or phenylation of germanane. By assuming the typical organic surface coverage of -33%, we have com- pared organically surface-modified germanane with germanene and germanane in the framework of density functional theory. It is found that organically surface-modified germanane may all stably exist despite the endothermic nature of organic surface modification. Organic surface modification leads to the de- crease of the Ge--Ge bond length and the Ge--Ge-Ge bond angle ofgermanane, while causing the buckling distance of germanane to increase. Hydrogenation makes germanene change from a semimetal to a direct- bandgap semiconductor. Organic surface modification further impacts the band structure of the resulting germanane. Hydrogermylated/alkoxylated germanane is a direct-bandgap semiconductor, while aminated/ phenylated germanane is an indirect-bandgap semiconductor. All the organic surface modification gives rise to the increase of the bandgap of germanane.
基金supported by the National Basic Research Program of China (Grant No. 2013CB632101)the National Natural Science Foundation of China (Grant Nos. 61222404 and 61474097)the Program of the Ministry of Education of China for Innovative Research Teams in Universities (Grant No. IRT13R54)
文摘The formation, structural and electronic properties of silicene oxides（SOs） that result from the oxidation of silicene on Ag（111） surface have been investigated in the framework of density functional theory（DFT）.It is found that the honeycomb lattice of silicene on the Ag（111） surface changes after the oxidation. SOs are strongly hybridized with the Ag（111） surface so that they possess metallic band structures. Charge accumulation between SOs and the Ag（111） surface indicates strong chemical bonding, which dramatically affects the electronic properties of SOs. When SOs are peeled off the Ag（111） surface, however, they may become semiconductors.
