Vertical nanowire arrays are increasingly investigated for their applications in steering cell behavior. The geometry of the array is an important parameter, which influences the morphology and adhesion of cells. Here...Vertical nanowire arrays are increasingly investigated for their applications in steering cell behavior. The geometry of the array is an important parameter, which influences the morphology and adhesion of cells. Here, we investigate the effects of array geometry on the morphology of MCF7 cancer cells and MCF10A normal-like epithelial cells. Different gallium phosphide nanowire array-geometries were produced by varying the nanowire density and diameter. Our results show that the cell size is smaller on nanowires compared to flat gallium phosphide. The cell area decreases with increasing the nanowire density on the substrate. We observed an effect of the nanowire diameter on MCF10A cells, with a decreased cell area on 40 nm diameter nanowires, compared to 60 and 80 nm diameter nanowires in high-density arrays. The focal adhesion morphology depends on the extent to which cells are contacting the substrate. For low nanowire densities and diameters, ceils are lying on the substrate and we observed large focal adhesions at the cell edges. In contrast, for high nanowire densities and diameters, cells are lying on top of the nanowires and we observed point-like focal adhesions distributed over the whole cell. Our results constitute a step towards the ability to fine-tune cell behavior on nanowire arrays.展开更多
Recently,cesium bismuth halide perovskites have emerged as potential substitutes to their counterparts,cesium lead halide perovskites,owing to their low toxicity.However,the photophysics of cesium-bismuth halides nano...Recently,cesium bismuth halide perovskites have emerged as potential substitutes to their counterparts,cesium lead halide perovskites,owing to their low toxicity.However,the photophysics of cesium-bismuth halides nanocrystals(NCs)have not yet been fully rationalized because their structures remain highly debated.The ultraviolet-visible(UV-vis)absorption along with other photophysical properties such as the nature and lifetime of the excited states vary considerably across the previous reports.Here,we successfully synthesize pure Cs_(3)BiBr_(6)and Cs_(3)Bi_(2)Br_(9)NCs via a modified hot-injection method,where the structure can be easily controlled by tuning the reaction temperature.The UV-vis absorption spectrum of the pure Cs_(3)Bi_(2)Br_(9)NCs features two characteristic peaks originating from the absorption of the first exciton and second exciton,respectively,which ultimately clarifies the debate in the previous reports.Using femtosecond transient absorption spectroscopy,we systematically investigate the excited state dynamics of the Cs_(3)Bi_(2)Br_(9)NCs and reveal that the photoexcited carriers undergo a self-trapping process within 3 ps after excitation.More intriguingly,the Cs_(3)Bi_(2)Br_(9)NCs prepared by this method show much better photostability than those prepared by the ligand-assisted reprecipitation process.Photodetectors based on these Cs_(3)Bi_(2)Br_(9)NCs show a sensitive light response,demonstrating the definite potential for breakthrough optoelectronic applications.展开更多
Photoinduced carrier dynamical processes dominate the optical excitation properties of photocatalysts and further determine the photocatalytic performance.In addition,as the electrons generally possess a faster transf...Photoinduced carrier dynamical processes dominate the optical excitation properties of photocatalysts and further determine the photocatalytic performance.In addition,as the electrons generally possess a faster transfer rate than holes,hole transfer and accumulation are critical,and they play the key efficiency-limiting step during the photocatalytic process.Therefore,a comprehensive understanding of the dynamics of photogenerated holes and their determining factors in the photocatalytic system is highly essential to rationalize the full catalytic mechanism and develop highly efficient photocatalysts,which have not yet been revealed.In this work,the photoinduced charge carrier dynamics in InP/ZnS quantum dots(QDs)capped with longchain L-typed ligands(oleylamine)and inorganic ligands(sulfide ion(S^(2-)))were explored.Time-resolved photoluminescence and femtosecond transient-absorption spectroscopy unambiguously confirmed the ultrafast hole transfer from the InP core to S^(2-)ligands.Moreover,by probing the bleach of vibrational stretching of the ligands with transient midinfrared absorption spectroscopy,the hole transfer time was determined to be 4.2 ps.The injected holes are long-lived at the S^(2-) ligands(>4.5 ns),and they can remove electrostatically attached surfactants to compensate for the spatial charge redistribution.Finally,compared with other inorganic ligands such as Cl^(-) and PO_(4)^(3-),S^(2-) balances the ionic radii and net charge to ensure the optimal condition for charge transfer.Such observation rationalizes the excellent photocatalytic H_(2) evolution(213.6μmol mg^(-1) within 10 h)in InP/ZnS QDs capped with S^(2-) compared with those capped with other ligands and elucidates the role of surface ligands in the photocatalytic activity of colloidal QDs.展开更多
环保型CuInSe_(2)量子点具有高消光系数和宽光谱吸收范围,在光电化学催化应用中展现了良好的发展前景.然而,CuInSe_(2)量子点较低的载流子分离能力和严重的界面电荷复合降低了其光电化学性能,制约了其应用.因此,我们设计并合成了具有Ⅱ...环保型CuInSe_(2)量子点具有高消光系数和宽光谱吸收范围,在光电化学催化应用中展现了良好的发展前景.然而,CuInSe_(2)量子点较低的载流子分离能力和严重的界面电荷复合降低了其光电化学性能,制约了其应用.因此,我们设计并合成了具有Ⅱ型能带排列的CuInSe_(2)/CuInS_(2)核/壳结构量子点,以促进载流子分离、减少界面缺陷;进一步通过调节In/Cu前驱体的摩尔比,产生铜空位.光物理性质研究表明,导带电子-铜空位捕获的空穴之间的辐射复合成为主要的复合方式,有效延长了载流子寿命,促进了载流子分离.因此,基于富铜空位的CuInSe_(2)/CuInS_(2)核壳量子点的光阳极获得了~8.0 mA cm^(-2)的最大饱和光电流密度,该性能是当前报道的CISe基量子点光电化学电池中的最高值之一.本工作提供了一种通过表面或内在缺陷的调控来促进光电化学应用中的电荷载流子分离和传输的有效方法.展开更多
基金supported by the Swedish Research Council (VR)Nano Lund, the Crafoord Foundation+1 种基金the China Scholarship Council (CSC)by a Donation from Carolina Le Prince with the “Kalenderflickorna” and Associated Sponsors
文摘Vertical nanowire arrays are increasingly investigated for their applications in steering cell behavior. The geometry of the array is an important parameter, which influences the morphology and adhesion of cells. Here, we investigate the effects of array geometry on the morphology of MCF7 cancer cells and MCF10A normal-like epithelial cells. Different gallium phosphide nanowire array-geometries were produced by varying the nanowire density and diameter. Our results show that the cell size is smaller on nanowires compared to flat gallium phosphide. The cell area decreases with increasing the nanowire density on the substrate. We observed an effect of the nanowire diameter on MCF10A cells, with a decreased cell area on 40 nm diameter nanowires, compared to 60 and 80 nm diameter nanowires in high-density arrays. The focal adhesion morphology depends on the extent to which cells are contacting the substrate. For low nanowire densities and diameters, ceils are lying on the substrate and we observed large focal adhesions at the cell edges. In contrast, for high nanowire densities and diameters, cells are lying on top of the nanowires and we observed point-like focal adhesions distributed over the whole cell. Our results constitute a step towards the ability to fine-tune cell behavior on nanowire arrays.
基金supported by the National Key Research and Development Program of China(2020YFA0309300)the Natural Science Foundation of Tianjin(20JCZDJC00560 and 20JCJQJC00210)+2 种基金the National Natural Science Foundation of China(NSFC,11974191 and 12127803)the 111 Project(B07013)the“Fundamental Research Funds for the Central Universities”,Nankai University(91923139,63213040,C029211101,C02922101,and ZB22000104)。
文摘Recently,cesium bismuth halide perovskites have emerged as potential substitutes to their counterparts,cesium lead halide perovskites,owing to their low toxicity.However,the photophysics of cesium-bismuth halides nanocrystals(NCs)have not yet been fully rationalized because their structures remain highly debated.The ultraviolet-visible(UV-vis)absorption along with other photophysical properties such as the nature and lifetime of the excited states vary considerably across the previous reports.Here,we successfully synthesize pure Cs_(3)BiBr_(6)and Cs_(3)Bi_(2)Br_(9)NCs via a modified hot-injection method,where the structure can be easily controlled by tuning the reaction temperature.The UV-vis absorption spectrum of the pure Cs_(3)Bi_(2)Br_(9)NCs features two characteristic peaks originating from the absorption of the first exciton and second exciton,respectively,which ultimately clarifies the debate in the previous reports.Using femtosecond transient absorption spectroscopy,we systematically investigate the excited state dynamics of the Cs_(3)Bi_(2)Br_(9)NCs and reveal that the photoexcited carriers undergo a self-trapping process within 3 ps after excitation.More intriguingly,the Cs_(3)Bi_(2)Br_(9)NCs prepared by this method show much better photostability than those prepared by the ligand-assisted reprecipitation process.Photodetectors based on these Cs_(3)Bi_(2)Br_(9)NCs show a sensitive light response,demonstrating the definite potential for breakthrough optoelectronic applications.
基金supported by the National Natural Science Foundation of China(NSFC,22002123 and U1862111)Sichuan Science and Technology Program(2020YFH0118,2021JDGD0029 and 2021YFH0055)+6 种基金the Open Fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(PLN201802)the Independent Research Fund Denmark-Nature Sciences(DFF-FNU,DFF-7014-00302)the Independent Research Fund Denmark-Sapere Aude starting grant(7026-00037A)the Research Fund for International Young Scientists from NSFC(21950410515)Swedish Research Council VR Starting Grant(2017-05337)the financial support from China Scholarship Council(201806320345,201908440313,201706170017,and 201806460021)Support from Swedish Energy Agency。
文摘Photoinduced carrier dynamical processes dominate the optical excitation properties of photocatalysts and further determine the photocatalytic performance.In addition,as the electrons generally possess a faster transfer rate than holes,hole transfer and accumulation are critical,and they play the key efficiency-limiting step during the photocatalytic process.Therefore,a comprehensive understanding of the dynamics of photogenerated holes and their determining factors in the photocatalytic system is highly essential to rationalize the full catalytic mechanism and develop highly efficient photocatalysts,which have not yet been revealed.In this work,the photoinduced charge carrier dynamics in InP/ZnS quantum dots(QDs)capped with longchain L-typed ligands(oleylamine)and inorganic ligands(sulfide ion(S^(2-)))were explored.Time-resolved photoluminescence and femtosecond transient-absorption spectroscopy unambiguously confirmed the ultrafast hole transfer from the InP core to S^(2-)ligands.Moreover,by probing the bleach of vibrational stretching of the ligands with transient midinfrared absorption spectroscopy,the hole transfer time was determined to be 4.2 ps.The injected holes are long-lived at the S^(2-) ligands(>4.5 ns),and they can remove electrostatically attached surfactants to compensate for the spatial charge redistribution.Finally,compared with other inorganic ligands such as Cl^(-) and PO_(4)^(3-),S^(2-) balances the ionic radii and net charge to ensure the optimal condition for charge transfer.Such observation rationalizes the excellent photocatalytic H_(2) evolution(213.6μmol mg^(-1) within 10 h)in InP/ZnS QDs capped with S^(2-) compared with those capped with other ligands and elucidates the role of surface ligands in the photocatalytic activity of colloidal QDs.
基金supported by the National Natural Science Foundation of China (52011530123,52272134,and 51902019)Beijing Natural Science Foundation (2222061 and 2232082)+4 种基金the IndustryUniversity-Research Cooperative Education of Ministry of Education (2205064205258 and 220606429170400)Shandong Weiqiao Pioneering Group Company Limited (BINTECH-KJZX-20220831-09 and BINTECHKJZX-20220831-29)the support from Swedish Research Council (2021-05319)Danish Villum Foundation Experiment Grant (50350)Swedish Foundation for International Cooperation in Research and Higher Education (F2020/1618)。
文摘环保型CuInSe_(2)量子点具有高消光系数和宽光谱吸收范围,在光电化学催化应用中展现了良好的发展前景.然而,CuInSe_(2)量子点较低的载流子分离能力和严重的界面电荷复合降低了其光电化学性能,制约了其应用.因此,我们设计并合成了具有Ⅱ型能带排列的CuInSe_(2)/CuInS_(2)核/壳结构量子点,以促进载流子分离、减少界面缺陷;进一步通过调节In/Cu前驱体的摩尔比,产生铜空位.光物理性质研究表明,导带电子-铜空位捕获的空穴之间的辐射复合成为主要的复合方式,有效延长了载流子寿命,促进了载流子分离.因此,基于富铜空位的CuInSe_(2)/CuInS_(2)核壳量子点的光阳极获得了~8.0 mA cm^(-2)的最大饱和光电流密度,该性能是当前报道的CISe基量子点光电化学电池中的最高值之一.本工作提供了一种通过表面或内在缺陷的调控来促进光电化学应用中的电荷载流子分离和传输的有效方法.
