The effect of deposition temperature on the morphology and optoelectronic performance of Ge/Si QDs grown by magnetron sputtering under low Ge deposition(~4 nm)was investigated by atomic force microscopy,Raman spectros...The effect of deposition temperature on the morphology and optoelectronic performance of Ge/Si QDs grown by magnetron sputtering under low Ge deposition(~4 nm)was investigated by atomic force microscopy,Raman spectroscopy,and photoluminescence(PL)tests.The experimental results indicate that temperatures higher than 750℃effectively increase the crystallization rate and surface smoothness of the Si buffer layer,and temperatures higher than 600℃significantly enhance the migration ability of Ge atoms,thus increasing the probability of Ge atoms meeting and nucleating to form QDs on Si buffer layer,but an excessively high temperature will cause the QDs to undergo an Ostwald ripening process and thus develop into super large islands.In addition,some PL peaks were observed in samples containing small-sized,high-density Ge QDs,the photoelectric properties reflected by these peaks were in good agreement with the corresponding structural characteristics of the grown QDs.Our results demonstrate the viability of preparing high-quality QDs by magnetron sputtering at high deposition rate,and the temperature effect is expected to work in conjunction with other controllable factors to further regulate QD growth,which paves an effective way for the industrial production of QDs that can be used in future devices.展开更多
Exploring high efficiency S-scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and importance.However,how to predict and regulate t...Exploring high efficiency S-scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and importance.However,how to predict and regulate the transport of photogenerated carriers in heterojunctions is a great challenge.Here,density functional theory calculations were first used to successfully predict the formation of a CdS quantum dots/InVO_(4)atomic-layer(110)/(110)facet S-scheme heterojunction.Subsequently,a CdS quantum dots/InVO_(4)atomic-layer was synthesized by in-situ loading of CdS quantum dots with(110)facets onto the(110)facets of InVO_(4)atomic-layer.As a result of the deliberately constructed built-in electric field between the adjoining facets,we obtain a remarkably enhanced photocatalytic degradation rate for ethylene.This rate is 13.8 times that of pure CdS and 13.2 times that of pure InVO_(4).In-situ irradiated X-ray photoelectron spectroscopy,photoluminescence and time-resolved photoluminescence measurements were carried out.These experiments validate that the built-in electric field enhanced the dissociation of photoexcited excitons and the separation of free charge carriers,and results in the formation of S-scheme charge transfer pathways.The reaction mechanism of the photocatalytic C_(2)H_(4)oxidation is investigated by in-situ electron paramagnetic resonance.This work provides a mechanistic insight into the construction and optimization of semiconductor heterojunction photocatalysts for application to environmental remediation.展开更多
鉴于四环素类抗生素大量使用造成的环境污染以及人体肝损伤、肠道功能紊乱和过敏等不良反应,亟需开发一种灵敏度高、操作简便、价格低廉的四环素类抗生素残留检测方法。荧光法具有操作简单、成本低廉、可视化等优点,因此,本工作基于MXen...鉴于四环素类抗生素大量使用造成的环境污染以及人体肝损伤、肠道功能紊乱和过敏等不良反应,亟需开发一种灵敏度高、操作简便、价格低廉的四环素类抗生素残留检测方法。荧光法具有操作简单、成本低廉、可视化等优点,因此,本工作基于MXene QDs和铕离子构建了可选择性检测强力霉素(DOX)的比率荧光探针。以尿酸和单层Ti3CN为原料通过水热法制备得MXene QDs,MXene QDs与Eu3+通过自组装构建得到MXene QDs-Eu3+双发射荧光探针,用于DOX的选择性检测。并通过优化探针体系中的MXene QDs浓度、Eu3+浓度、pH和响应时间等实验条件,探究该双发射荧光探针对强力霉素的定量和选择性检测性能。结果表明,该荧光探针对DOX具有特异性识别能力,且荧光强度比(F615/F421)与不同浓度DOX (0∼30 μM)之间存在良好的线性关系,表明其在TCs残留检测中具有良好应用前景。Given the environmental pollution, liver damage, intestinal dysfunction, and allergic reactions caused by the extensive use of tetracycline antibiotics, there is an urgent need to develop a sensitive, simple, and cost-effective method for detecting residual tetracycline antibiotics. The fluorescence method possesses advantages such as simple operation, low cost, and visualizability. Therefore, this work constructs a ratio fluorescence probe for the selective detection of doxycycline based on MXene QDs and rare earth ions. We prepared MXene QDs using uric acid and single-layer Ti3CN as raw materials through a hydrothermal method. The MXene QDs-Eu3+ dual-emission fluorescent probe was constructed by self-assembly of MXene QDs and Eu3+, which was used for the selective detection of streptomycin. By optimizing the experimental conditions such as the concentration of MXene QDs, Eu3+, pH, and response time in the probe system, this dual-emission fluorescent probe was explored for quantitative and selective detection of streptomycin. Findings show that the fluorescent probe uniquely identifies gentamicin, with a strong linear correlation between the fluorescence intensity ratio (F615/F421) and different gentamicin concentrations (0~30 μM), hinting at its potential use in identifying tetracycline residues.展开更多
采用简单液相沉积法制备了分级结构Cd S QDs/Bi OCl复合光催化剂,以XRD,SEM,TEM,HRTEM,XPS,EDS,UV-Vis DRS,PL等测试方法分别表征了样品的物相、形貌、组成、元素含量、光吸收性能以及光电特性,并以罗丹明B(Rh B)和苯酚为模型污染物,分...采用简单液相沉积法制备了分级结构Cd S QDs/Bi OCl复合光催化剂,以XRD,SEM,TEM,HRTEM,XPS,EDS,UV-Vis DRS,PL等测试方法分别表征了样品的物相、形貌、组成、元素含量、光吸收性能以及光电特性,并以罗丹明B(Rh B)和苯酚为模型污染物,分别在可见光和紫外光下评价Cd S QDs/Bi OCl复合光催化剂的催化性能。测试结果表明,粒径为5.5μm的Bi OCl微球由大量纳米片有序堆积而成,所负载的粒径为10~20 nm的Cd S QDs均匀分布在Bi OCl纳米片表面。与纯Bi OCl和Cd S QDs/Bi OCl相比,Cd S QDs/Bi OCl-3%表现出最佳的光催化性能,其对Rh B和苯酚的降解速率常数分别是纯Bi OCl的2.6倍和5.3倍。Cd S QDs/Bi OCl复合光催化剂性能的提高可归结于,分级结构Bi OCl有效防止了片层堆积,有助于Cd S QDs的负载,另外,Cd S QDs的负载拓展了复合光催化剂的光吸收性能,均匀分布的Cd S QDs与Bi OCl形成的异质结促进了光生电子-空穴对的有效分离。展开更多
Semiconductor quantum dots(QDs) were used for labeling many biomacromolecules and small molecules,but it remains a challenge to couple it with short active peptides without any limitation,which play critical roles in ...Semiconductor quantum dots(QDs) were used for labeling many biomacromolecules and small molecules,but it remains a challenge to couple it with short active peptides without any limitation,which play critical roles in many physiological processes.Several coupling methods known about QDs and short peptides have some limitations.In this research,we report a method for the synthesis of QDs labeled peptides to be appropriate to any short peptide.The QDs(CdTe)-labeled short peptides were verified and characterized by RP-HPLC.The result shows that the surface of the T cell treated with QDs-TP5 emits yellow fluoresence.These results indicate that QDs-TP5 tends to aggregate on the surface of T cells.They were applied to monitoring the specific binding between the immune peptides and T cell surface receptors.The binding and the resultant fluorescence were observed and monitored by fluorescence microscope in vitro.The QDs-labeled immune peptides provide a powerful method for studying the immune modulating activity of TP5 in vivo.展开更多
目的制备毒性低,生物相容性好的新型半导体量子点。方法以还原型谷胱甘肽（GSH）为硫源和稳定剂,采用水热法合成Cd Te/Cd S QDs。结果制备的GSH包裹的Cd Te/Cd S QDs波长范围覆盖400~800 nm的区域,量子产率高达83.1%,平均粒径约为3 nm...目的制备毒性低,生物相容性好的新型半导体量子点。方法以还原型谷胱甘肽（GSH）为硫源和稳定剂,采用水热法合成Cd Te/Cd S QDs。结果制备的GSH包裹的Cd Te/Cd S QDs波长范围覆盖400~800 nm的区域,量子产率高达83.1%,平均粒径约为3 nm。结论该Cd Te/Cd S QDs制备方法简便,成本低,有效降低了量子点生物毒性。展开更多
基金Founded by the National Key Research and Development Program(No.2021YFB3802400)the National Natural Science Foundation of China(No.52161037)the Basic Research Project of Yunnan Province(No.202001AU070112)。
文摘The effect of deposition temperature on the morphology and optoelectronic performance of Ge/Si QDs grown by magnetron sputtering under low Ge deposition(~4 nm)was investigated by atomic force microscopy,Raman spectroscopy,and photoluminescence(PL)tests.The experimental results indicate that temperatures higher than 750℃effectively increase the crystallization rate and surface smoothness of the Si buffer layer,and temperatures higher than 600℃significantly enhance the migration ability of Ge atoms,thus increasing the probability of Ge atoms meeting and nucleating to form QDs on Si buffer layer,but an excessively high temperature will cause the QDs to undergo an Ostwald ripening process and thus develop into super large islands.In addition,some PL peaks were observed in samples containing small-sized,high-density Ge QDs,the photoelectric properties reflected by these peaks were in good agreement with the corresponding structural characteristics of the grown QDs.Our results demonstrate the viability of preparing high-quality QDs by magnetron sputtering at high deposition rate,and the temperature effect is expected to work in conjunction with other controllable factors to further regulate QD growth,which paves an effective way for the industrial production of QDs that can be used in future devices.
基金financially supported by the National Natural Science Foundation of China(Grant No.21902046,21801071,12174092,U21A20500)Overseas Expertise Introduction Center for Discipline Innovation(D18025)+3 种基金the Natural Science Foundation of Hubei Provincial(Grant No.2018CFB171)Wuhan Science and Technology Bureau(2020010601012163)Science and Technology Research Project of Hubei Provincial Department of Education(No.D20221001)the open foundation of the State Key Laboratory of Structural Chemistry,Fujian Institute of Research on the Structure of Matter,Chinese Academy of Sciences
文摘Exploring high efficiency S-scheme heterojunction photocatalysts with strong redox ability for removing volatile organic compounds from the air is of great interest and importance.However,how to predict and regulate the transport of photogenerated carriers in heterojunctions is a great challenge.Here,density functional theory calculations were first used to successfully predict the formation of a CdS quantum dots/InVO_(4)atomic-layer(110)/(110)facet S-scheme heterojunction.Subsequently,a CdS quantum dots/InVO_(4)atomic-layer was synthesized by in-situ loading of CdS quantum dots with(110)facets onto the(110)facets of InVO_(4)atomic-layer.As a result of the deliberately constructed built-in electric field between the adjoining facets,we obtain a remarkably enhanced photocatalytic degradation rate for ethylene.This rate is 13.8 times that of pure CdS and 13.2 times that of pure InVO_(4).In-situ irradiated X-ray photoelectron spectroscopy,photoluminescence and time-resolved photoluminescence measurements were carried out.These experiments validate that the built-in electric field enhanced the dissociation of photoexcited excitons and the separation of free charge carriers,and results in the formation of S-scheme charge transfer pathways.The reaction mechanism of the photocatalytic C_(2)H_(4)oxidation is investigated by in-situ electron paramagnetic resonance.This work provides a mechanistic insight into the construction and optimization of semiconductor heterojunction photocatalysts for application to environmental remediation.
文摘鉴于四环素类抗生素大量使用造成的环境污染以及人体肝损伤、肠道功能紊乱和过敏等不良反应,亟需开发一种灵敏度高、操作简便、价格低廉的四环素类抗生素残留检测方法。荧光法具有操作简单、成本低廉、可视化等优点,因此,本工作基于MXene QDs和铕离子构建了可选择性检测强力霉素(DOX)的比率荧光探针。以尿酸和单层Ti3CN为原料通过水热法制备得MXene QDs,MXene QDs与Eu3+通过自组装构建得到MXene QDs-Eu3+双发射荧光探针,用于DOX的选择性检测。并通过优化探针体系中的MXene QDs浓度、Eu3+浓度、pH和响应时间等实验条件,探究该双发射荧光探针对强力霉素的定量和选择性检测性能。结果表明,该荧光探针对DOX具有特异性识别能力,且荧光强度比(F615/F421)与不同浓度DOX (0∼30 μM)之间存在良好的线性关系,表明其在TCs残留检测中具有良好应用前景。Given the environmental pollution, liver damage, intestinal dysfunction, and allergic reactions caused by the extensive use of tetracycline antibiotics, there is an urgent need to develop a sensitive, simple, and cost-effective method for detecting residual tetracycline antibiotics. The fluorescence method possesses advantages such as simple operation, low cost, and visualizability. Therefore, this work constructs a ratio fluorescence probe for the selective detection of doxycycline based on MXene QDs and rare earth ions. We prepared MXene QDs using uric acid and single-layer Ti3CN as raw materials through a hydrothermal method. The MXene QDs-Eu3+ dual-emission fluorescent probe was constructed by self-assembly of MXene QDs and Eu3+, which was used for the selective detection of streptomycin. By optimizing the experimental conditions such as the concentration of MXene QDs, Eu3+, pH, and response time in the probe system, this dual-emission fluorescent probe was explored for quantitative and selective detection of streptomycin. Findings show that the fluorescent probe uniquely identifies gentamicin, with a strong linear correlation between the fluorescence intensity ratio (F615/F421) and different gentamicin concentrations (0~30 μM), hinting at its potential use in identifying tetracycline residues.
文摘采用简单液相沉积法制备了分级结构Cd S QDs/Bi OCl复合光催化剂,以XRD,SEM,TEM,HRTEM,XPS,EDS,UV-Vis DRS,PL等测试方法分别表征了样品的物相、形貌、组成、元素含量、光吸收性能以及光电特性,并以罗丹明B(Rh B)和苯酚为模型污染物,分别在可见光和紫外光下评价Cd S QDs/Bi OCl复合光催化剂的催化性能。测试结果表明,粒径为5.5μm的Bi OCl微球由大量纳米片有序堆积而成,所负载的粒径为10~20 nm的Cd S QDs均匀分布在Bi OCl纳米片表面。与纯Bi OCl和Cd S QDs/Bi OCl相比,Cd S QDs/Bi OCl-3%表现出最佳的光催化性能,其对Rh B和苯酚的降解速率常数分别是纯Bi OCl的2.6倍和5.3倍。Cd S QDs/Bi OCl复合光催化剂性能的提高可归结于,分级结构Bi OCl有效防止了片层堆积,有助于Cd S QDs的负载,另外,Cd S QDs的负载拓展了复合光催化剂的光吸收性能,均匀分布的Cd S QDs与Bi OCl形成的异质结促进了光生电子-空穴对的有效分离。
文摘Semiconductor quantum dots(QDs) were used for labeling many biomacromolecules and small molecules,but it remains a challenge to couple it with short active peptides without any limitation,which play critical roles in many physiological processes.Several coupling methods known about QDs and short peptides have some limitations.In this research,we report a method for the synthesis of QDs labeled peptides to be appropriate to any short peptide.The QDs(CdTe)-labeled short peptides were verified and characterized by RP-HPLC.The result shows that the surface of the T cell treated with QDs-TP5 emits yellow fluoresence.These results indicate that QDs-TP5 tends to aggregate on the surface of T cells.They were applied to monitoring the specific binding between the immune peptides and T cell surface receptors.The binding and the resultant fluorescence were observed and monitored by fluorescence microscope in vitro.The QDs-labeled immune peptides provide a powerful method for studying the immune modulating activity of TP5 in vivo.
文摘目的制备毒性低,生物相容性好的新型半导体量子点。方法以还原型谷胱甘肽（GSH）为硫源和稳定剂,采用水热法合成Cd Te/Cd S QDs。结果制备的GSH包裹的Cd Te/Cd S QDs波长范围覆盖400~800 nm的区域,量子产率高达83.1%,平均粒径约为3 nm。结论该Cd Te/Cd S QDs制备方法简便,成本低,有效降低了量子点生物毒性。
