Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle...Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle-dependent HDPC,it is found that the HDPC is mainly contributed by the circular photogalvanic effect(CPGE)current when the incident plane is perpendicular to the connection of the two contacts,whereas the circular photon drag effect(CPDE)dominates the HDPC when the incident plane is parallel to the connection of the two contacts.In addition,the CPGE of the(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate is regulated by temperature,light power,excitation wavelength,the source–drain and ionic liquid top-gate voltages,and the regulation mechanisms are discussed.It is demonstrated that(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplates may provide a good platform for novel opto-spintronics devices.展开更多
本文报道用分子束外延(Molecular Beam Epitaxy:MBE)技术制备了优良的铬(Cr)掺杂硒化铋(Cr-Bi_(2)Se_(3))薄膜样品。通过反射高能电子衍射(Reflective High Energy Electron Diffraction:RHEED)、X射线衍射(X-ray diffraction:XRD)技术...本文报道用分子束外延(Molecular Beam Epitaxy:MBE)技术制备了优良的铬(Cr)掺杂硒化铋(Cr-Bi_(2)Se_(3))薄膜样品。通过反射高能电子衍射(Reflective High Energy Electron Diffraction:RHEED)、X射线衍射(X-ray diffraction:XRD)技术和电磁输运系统对Cr-Bi_(2)Se_(3)进行测试。实验结果显示:较低的生长温度下Cr进入Bi_(2)Se_(3)中替代Bi位形成Cr Bi;较高的生长温度下Cr进入Bi_(2)Se_(3)中的范德瓦尔斯间隙形成层间(Interlayer)CrI,这一区别导致Cr-Bi_(2)Se_(3)在生长速率及磁性等方面表现出不同的性质。所以可以通过控制生长温度来调制Cr的掺杂位置,得到更理想的效果。展开更多
The results of experimental investigation of n-type semiconductor based on Bi2Te3 alloy were presented. This material is used in manufacture of thermoelectric coolers and electrical power generation devices. BizTe2.88...The results of experimental investigation of n-type semiconductor based on Bi2Te3 alloy were presented. This material is used in manufacture of thermoelectric coolers and electrical power generation devices. BizTe2.88Se0.12 solid solution single crystal has been grown using the Czochralski method. Monitoring of structure changes of the sample was carried out by electron microscope. The elemental composition of the studied alloy was obtained by energy dispersive spectrometry （EDS） analysis and empirical formula of the compound was established. X-ray diffraction analysis confirmed that the Bi2Te2.88Se0.12 sample was a single phase with rhombohedral structure. The behavior upon heating was studied using differential thermal analysis （DTA） technique. Changes in physical and chemical properties of materials were measured as a function of increasing temperature by thermogravimetric analysis （TGA）. The lattice parameters values obtained by X-ray powder diffraction analyses of Bi2Te2.88Se0.12 are very similar to BizTe3 lattice constants, indicating that a small portion of tellurium is replaced with selenium. The obtained values for specific electrical and thermal conductivities are in correlation with available literature data. The Vickers microhardness values are in range between HV 187 and HV 39.02 and decrease with load increasing. It is shown that very complex process of infrared thermography can be applied for characterization of thermoelectric elements and modules.展开更多
Copper-doped Bi_(2)Se_(3)(Cu_(x)Bi_(2)Se_(3))is of considerable interest for tailoring its electronic properties and inducing exotic charge correlations while retaining the unique Dirac surface states.However,the copp...Copper-doped Bi_(2)Se_(3)(Cu_(x)Bi_(2)Se_(3))is of considerable interest for tailoring its electronic properties and inducing exotic charge correlations while retaining the unique Dirac surface states.However,the copper dopants in Cu_(x)Bi_(2)Se_(3) display complex electronic behaviors and may function as either electron donors or acceptors depending on their concentration and atomic sites within the Bi_(2)Se_(3) crystal lattice.Thus,a precise understanding and control of the doping concentration and sites is of both fundamental and practical significance.Herein,we report a solution-based one-pot synthesis of Cu_(x)Bi_(2)Se_(3) nanoplates with systematically tunable Cu doping concentrations and doping sites.Our studies reveal a gradual evolution from intercalative sites to substitutional sites with increasing Cu concentrations.The Cu atoms at intercalative sites function as electron donors while those at the substitutional sites function as electron acceptors,producing distinct effects on the electronic properties of the resulting materials.We further show that Cu_(0.18)Bi_(2)Se_(3) exhibits superconducting behavior,which is not present in Bi_(2)Se_(3),highlighting the essential role of Cu doping in tailoring exotic quantum properties.This study establishes an efficient methodology for precise synthesis of Cu_(x)Bi_(2)Se_(3) with tailored doping concentrations,doping sites,and electronic properties.展开更多
Bi_(2)Se_(3)-based flexible thin film with high thermoelectric performance is promising for the waste heat recovery technology.In this work,a novel post-selenization method is employed to prepare n-type Bi_(2)Se_(3)fl...Bi_(2)Se_(3)-based flexible thin film with high thermoelectric performance is promising for the waste heat recovery technology.In this work,a novel post-selenization method is employed to prepare n-type Bi_(2)Se_(3)flexible thin films with highly textured structure.The strengthened texture and Se vacancy optimization can be simultaneously achieved by optimizing the selenization temperature.The highly oriented texture leads to the increased carrier mobility and results in a high electric conductivity of~290.47 S·cm^(-1)at 623 K.Correspondingly,a high Seebeck coefficient(>110μW·K-1)is obtained due to the reduced carrier concentration,induced by optimizing vacancy engineering.Consequently,a high power factor of 3.49μW·cm^(-1)·K^(-2)at 623 K has been achieved in asprepared highly-bendable Bi_(2)Se_(3)flexible thin films selenized at 783 K.This study introduces an effective post-selenization method to tune the texture structure and vacancies of Bi_(2)Se_(3)flexible thin films,and correspondingly achieves high thermoelectric performance.展开更多
Self-powered full-spectrum photodetectors(PDs)offer numerous advantages,such as broad application fields,high precision,efficiency,and multi-functionality,which represent a highly promising and potentially valuable cl...Self-powered full-spectrum photodetectors(PDs)offer numerous advantages,such as broad application fields,high precision,efficiency,and multi-functionality,which represent a highly promising and potentially valuable class of detectors for future development.However,insensitive response to solar-blind ultraviolet(UV)and complex and expensive preparation processes greatly limit their performance and practical application.In this study,a self-powered full-spectrum Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with high sensitivity for solar-blind UV band prepared by a simple and low-cost two-step synthesis method is presented.Experiments results reveal that the developed PD has an excellent performance,such as high sensitivity from 200 to 850 nm,and a responsivity of 1.38 mA/W as well as a detectivity of 3.22×10^(10) Jones under 254 nm light at zero bias.Additionally,the unencapsulated device displays exceptional stability and imaging capabilities.It is expected that Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with a simple and low-cost synthesis method has great potential for self-powered full-spectrum photodetectors.展开更多
We present a controlled,stepwise formation of layered semiconductor Bi_(2)O_(2)Se thin films prepared via the vapour process by annealing topological insulator Bi_(2)Se3 thin films in low oxygen atmosphere for differe...We present a controlled,stepwise formation of layered semiconductor Bi_(2)O_(2)Se thin films prepared via the vapour process by annealing topological insulator Bi_(2)Se3 thin films in low oxygen atmosphere for different reactions.Photodetectors based on Bi_(2)O_(2)Se thin film show a responsivity of 1.7×10^(4) A/W at a wavelength of 980 nm.Field-effect transistors based on Bi_(2)O_(2)Se thin film exhibit n-type behavior and present a high electron mobility of 17 cm^(2)/V·s.In addition,the electrical properties of the devices after 4 months keeping in the air shows little change,implying outstanding air-stability of our Bi_(2)O_(2)Se thin films.From the obtained results,it is evident that low oxygen annealing is a surprisingly effective method to fabricate Bi_(2)O_(2)Se thin films for integrated optoelectronic applications.展开更多
Recently,two-dimension(2D)materials have fueled considerable interest in the field of gas sensing to cope urgent demands at specific scenarios.Unfortunately,the susceptibility to ambient humidity,and/or fragile operat...Recently,two-dimension(2D)materials have fueled considerable interest in the field of gas sensing to cope urgent demands at specific scenarios.Unfortunately,the susceptibility to ambient humidity,and/or fragile operation stability always frustrate their further practicability.To overcome these drawbacks,we proposed one novel flexible gas sensor based on bismuth selenide(Bi_(2)Se_(3))nanoplates for sensitive NO_(2)detection at room temperature.The as-prepared Bi_(2)Se_(3)sensor exhibited favorable sensing performance,including remarkable NO_(2)selectivity,high response of 120%and fast response time of 81 s toward 5ppm NO_(2),an ultralow detection limit of 100 ppb,and nice stability.Besides,the excellent humidity tolerance and mechanical flexibility endowed Bi_(2)Se_(3)sensors with admirable reliability under harsh working conditions.The first-principles calculation further revealed the insights of extraordinary NO_(2)selectivity and the underlying gas-sensing mechanism.展开更多
Heterostructures based on new advanced materials offer a cornerstone for future optoelectronic devices with improved photoelectric performance.Band alignment is crucial for understanding the mechanism of charge carrie...Heterostructures based on new advanced materials offer a cornerstone for future optoelectronic devices with improved photoelectric performance.Band alignment is crucial for understanding the mechanism of charge carrier transportation and interface dynamics in heterostructures.Herein,we grew SnS_(2)/Bi_(2)X_(3)(X=Se,Te)van der Waals heterostructures by combining physical vapor deposition with chemical vapor deposition.The band alignment,measured by high-resolution X-ray photoelectron spectroscopy,suggested the successful design of type-Ⅰ SnS_(2)/Bi_(2)Te_(3) and type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructures.The SnS_(2)/Bi_(2)X_(3) heterostructure greatly improved the photoelectric response of a photoelectrochemical-type photodetector.The photocurrent densities in the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) and type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructure-based devices were more than one order of magnitude higher than those of SnS_(2),Bi_(2)Te_(3),and Bi_(2)Te_(3).The improved photoelectric properties of the SnS_(2)/Bi_(2)X_(3) heterostructures can be explained as follows:(i)the photoexcited electrons and holes are effectively separated in the heterostructures;(ii)the charge-transfer efficiency and carrier density at the interface between the SnS_(2)/Bi_(2)X_(3) heterostructures and the electrolyte are greatly improved;(iii)the formed heterostructures expand the light absorption range.The photoelectric performance was further enhanced by efficient light trapping in the upright SnS_(2).The photoelectric response is higher in the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) heterostructure than in the type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructure due to more efficient charge transportation at the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) heterostructure/electrolyte interface.These results suggest that suitable type-Ⅰ and type-Ⅱ heterostructures can be developed for high-performance photodetectors and other optoelectronic devices.展开更多
Harsh photothermal temperatures(>50℃)caused heating damage to the normal tissues and induced thermal resistance in cancer cells,which significantly limited the safety and efficacy of photothermal therapy(PTT)in ca...Harsh photothermal temperatures(>50℃)caused heating damage to the normal tissues and induced thermal resistance in cancer cells,which significantly limited the safety and efficacy of photothermal therapy(PTT)in cancer treatment.Mild hyperthermia(<42℃)combined with chemotherapy might solve this issue.Herein,a novel transition metal dichalcogenides nanostructure,namely,Bi_(2)Se_(3)/MoSe_(2)nanosaucers(BMNSs),was designed to produce mild photo-hyperthermia(mPTT)and combined with chemotherapy to improve the overall antitumor efficacy.The BMNSs were constituted by Bi_(2)Se_(3)hexagonal nanoplates and enclosed with MoSe_(2)nanosheets evenly.While the MoSe_(2)moiety endowed the nanoplatform with excellent photothermal efficacy,the Bi_(2)Se_(3)substrates provided large specific surface area to anchor more doxorubicin(DOX)molecules as chemotherapeutic agent.Under the stimuli of mPTT/tumor acidic microenvironment,the tumor-specific drug release and the enhanced chemotherapy could be realized,showing impressive therapeutic outcomes against 4T1 cells.The synergetic therapeutic mechanism might be attributed to the mPTT induced cell membrane permeability,and interestingly,the expression of heat shock proteins 70 was not elevated obviously after the synergetic therapy,thus to avoid the tumor thermal resistance and further improve the therapeutic effect.The in vivo anti-tumoral performance of the BMNSs was further studied and complete tumor eradication was achieved without any recurrence and biotoxicity.Not only demonstrating a paradigm of high therapeutic efficacy of mild hyperthermia and synergistic chemotherapy for precise cancer therapy,our findings proved that the cancer therapeutic effect can be improved with minimal side effects through exquisite designing of the microstructures and the physiochemical properties of the nanoplatform.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62074036,61674038,and 11574302)the Foreign Cooperation Project of Fujian Province,China(Grant No.2023I0005)+2 种基金the Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics(Grant No.KF202108)the National Key Research and Development Program of China(Grant No.2016YFB0402303)the Foundation of Fujian Provincial Department of Industry and Information Technology of China(Grant No.82318075)。
文摘Helicity-dependent photocurrent(HDPC)of the surface states in a high-quality topological insulator(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate grown by chemical vapor deposition(CVD)is investigated.By investigating the angle-dependent HDPC,it is found that the HDPC is mainly contributed by the circular photogalvanic effect(CPGE)current when the incident plane is perpendicular to the connection of the two contacts,whereas the circular photon drag effect(CPDE)dominates the HDPC when the incident plane is parallel to the connection of the two contacts.In addition,the CPGE of the(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplate is regulated by temperature,light power,excitation wavelength,the source–drain and ionic liquid top-gate voltages,and the regulation mechanisms are discussed.It is demonstrated that(Bi_(0.7)Sb_(0.3))_(2)Te_(3)nanoplates may provide a good platform for novel opto-spintronics devices.
文摘本文报道用分子束外延(Molecular Beam Epitaxy:MBE)技术制备了优良的铬(Cr)掺杂硒化铋(Cr-Bi_(2)Se_(3))薄膜样品。通过反射高能电子衍射(Reflective High Energy Electron Diffraction:RHEED)、X射线衍射(X-ray diffraction:XRD)技术和电磁输运系统对Cr-Bi_(2)Se_(3)进行测试。实验结果显示:较低的生长温度下Cr进入Bi_(2)Se_(3)中替代Bi位形成Cr Bi;较高的生长温度下Cr进入Bi_(2)Se_(3)中的范德瓦尔斯间隙形成层间(Interlayer)CrI,这一区别导致Cr-Bi_(2)Se_(3)在生长速率及磁性等方面表现出不同的性质。所以可以通过控制生长温度来调制Cr的掺杂位置,得到更理想的效果。
基金"Development of ecological knowledge-based advanced materials and technologies for multifunctional application" (Grant No.TR34005)"New approach to designing materials for energy conversion and storage" (Grant No.OI172060)"0-3D nanostructures for application in electronics and renewable energy sources:synthesis,characterisation and processing" (Grant No.III45007)
文摘The results of experimental investigation of n-type semiconductor based on Bi2Te3 alloy were presented. This material is used in manufacture of thermoelectric coolers and electrical power generation devices. BizTe2.88Se0.12 solid solution single crystal has been grown using the Czochralski method. Monitoring of structure changes of the sample was carried out by electron microscope. The elemental composition of the studied alloy was obtained by energy dispersive spectrometry （EDS） analysis and empirical formula of the compound was established. X-ray diffraction analysis confirmed that the Bi2Te2.88Se0.12 sample was a single phase with rhombohedral structure. The behavior upon heating was studied using differential thermal analysis （DTA） technique. Changes in physical and chemical properties of materials were measured as a function of increasing temperature by thermogravimetric analysis （TGA）. The lattice parameters values obtained by X-ray powder diffraction analyses of Bi2Te2.88Se0.12 are very similar to BizTe3 lattice constants, indicating that a small portion of tellurium is replaced with selenium. The obtained values for specific electrical and thermal conductivities are in correlation with available literature data. The Vickers microhardness values are in range between HV 187 and HV 39.02 and decrease with load increasing. It is shown that very complex process of infrared thermography can be applied for characterization of thermoelectric elements and modules.
基金the UCLA California NanoSystem Institute(CNSI)Noble Family Innovation Fund for material preparationpartial support from the National Science Foundation through grant number 2329192 for transport studies and analysis.
文摘Copper-doped Bi_(2)Se_(3)(Cu_(x)Bi_(2)Se_(3))is of considerable interest for tailoring its electronic properties and inducing exotic charge correlations while retaining the unique Dirac surface states.However,the copper dopants in Cu_(x)Bi_(2)Se_(3) display complex electronic behaviors and may function as either electron donors or acceptors depending on their concentration and atomic sites within the Bi_(2)Se_(3) crystal lattice.Thus,a precise understanding and control of the doping concentration and sites is of both fundamental and practical significance.Herein,we report a solution-based one-pot synthesis of Cu_(x)Bi_(2)Se_(3) nanoplates with systematically tunable Cu doping concentrations and doping sites.Our studies reveal a gradual evolution from intercalative sites to substitutional sites with increasing Cu concentrations.The Cu atoms at intercalative sites function as electron donors while those at the substitutional sites function as electron acceptors,producing distinct effects on the electronic properties of the resulting materials.We further show that Cu_(0.18)Bi_(2)Se_(3) exhibits superconducting behavior,which is not present in Bi_(2)Se_(3),highlighting the essential role of Cu doping in tailoring exotic quantum properties.This study establishes an efficient methodology for precise synthesis of Cu_(x)Bi_(2)Se_(3) with tailored doping concentrations,doping sites,and electronic properties.
基金financially supported by the Natural Science Foundations of Shandong Province(No.ZR2023ME001)the China Postdoctoral Science Foundation(No.2023M732609)+1 种基金ShangRao City of Jiangxi Province(China)(No.2022A006)Doctoral Research Initiation Fund of Weifang University(No.2023BS01)。
文摘Bi_(2)Se_(3)-based flexible thin film with high thermoelectric performance is promising for the waste heat recovery technology.In this work,a novel post-selenization method is employed to prepare n-type Bi_(2)Se_(3)flexible thin films with highly textured structure.The strengthened texture and Se vacancy optimization can be simultaneously achieved by optimizing the selenization temperature.The highly oriented texture leads to the increased carrier mobility and results in a high electric conductivity of~290.47 S·cm^(-1)at 623 K.Correspondingly,a high Seebeck coefficient(>110μW·K-1)is obtained due to the reduced carrier concentration,induced by optimizing vacancy engineering.Consequently,a high power factor of 3.49μW·cm^(-1)·K^(-2)at 623 K has been achieved in asprepared highly-bendable Bi_(2)Se_(3)flexible thin films selenized at 783 K.This study introduces an effective post-selenization method to tune the texture structure and vacancies of Bi_(2)Se_(3)flexible thin films,and correspondingly achieves high thermoelectric performance.
基金support from the National Key R&D Program of China(No.2019YFA0705201)the National Natural Science Foundation of China(No.62174042)the Heilongjiang Touyan Team.
文摘Self-powered full-spectrum photodetectors(PDs)offer numerous advantages,such as broad application fields,high precision,efficiency,and multi-functionality,which represent a highly promising and potentially valuable class of detectors for future development.However,insensitive response to solar-blind ultraviolet(UV)and complex and expensive preparation processes greatly limit their performance and practical application.In this study,a self-powered full-spectrum Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with high sensitivity for solar-blind UV band prepared by a simple and low-cost two-step synthesis method is presented.Experiments results reveal that the developed PD has an excellent performance,such as high sensitivity from 200 to 850 nm,and a responsivity of 1.38 mA/W as well as a detectivity of 3.22×10^(10) Jones under 254 nm light at zero bias.Additionally,the unencapsulated device displays exceptional stability and imaging capabilities.It is expected that Bi_(2)Se_(3)/a-Ga_(2)O_(3)/p-Si heterojunction PD with a simple and low-cost synthesis method has great potential for self-powered full-spectrum photodetectors.
基金supported by the Hunan Provincial Natural Science Foundation of China(Grant No.2019JJ40032)。
文摘We present a controlled,stepwise formation of layered semiconductor Bi_(2)O_(2)Se thin films prepared via the vapour process by annealing topological insulator Bi_(2)Se3 thin films in low oxygen atmosphere for different reactions.Photodetectors based on Bi_(2)O_(2)Se thin film show a responsivity of 1.7×10^(4) A/W at a wavelength of 980 nm.Field-effect transistors based on Bi_(2)O_(2)Se thin film exhibit n-type behavior and present a high electron mobility of 17 cm^(2)/V·s.In addition,the electrical properties of the devices after 4 months keeping in the air shows little change,implying outstanding air-stability of our Bi_(2)O_(2)Se thin films.From the obtained results,it is evident that low oxygen annealing is a surprisingly effective method to fabricate Bi_(2)O_(2)Se thin films for integrated optoelectronic applications.
基金This work was partially supported by Fundamental and Frontier Research Project of Chongqing(Nos.cstc2019jcyj-msxmX0037 and cstc2020jcyj-msxmX1041)National Natural Science Foundation of China(Nos.61704014 and 52175281)Youth Innovation Promotion Association of CAS(No.2021382).
文摘Recently,two-dimension(2D)materials have fueled considerable interest in the field of gas sensing to cope urgent demands at specific scenarios.Unfortunately,the susceptibility to ambient humidity,and/or fragile operation stability always frustrate their further practicability.To overcome these drawbacks,we proposed one novel flexible gas sensor based on bismuth selenide(Bi_(2)Se_(3))nanoplates for sensitive NO_(2)detection at room temperature.The as-prepared Bi_(2)Se_(3)sensor exhibited favorable sensing performance,including remarkable NO_(2)selectivity,high response of 120%and fast response time of 81 s toward 5ppm NO_(2),an ultralow detection limit of 100 ppb,and nice stability.Besides,the excellent humidity tolerance and mechanical flexibility endowed Bi_(2)Se_(3)sensors with admirable reliability under harsh working conditions.The first-principles calculation further revealed the insights of extraordinary NO_(2)selectivity and the underlying gas-sensing mechanism.
基金supported by the National Natural Science Foundation of China(12074311,11774288,11974279)the Natural Science Foundation of Shaanxi Province(2019JC-25)。
文摘Heterostructures based on new advanced materials offer a cornerstone for future optoelectronic devices with improved photoelectric performance.Band alignment is crucial for understanding the mechanism of charge carrier transportation and interface dynamics in heterostructures.Herein,we grew SnS_(2)/Bi_(2)X_(3)(X=Se,Te)van der Waals heterostructures by combining physical vapor deposition with chemical vapor deposition.The band alignment,measured by high-resolution X-ray photoelectron spectroscopy,suggested the successful design of type-Ⅰ SnS_(2)/Bi_(2)Te_(3) and type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructures.The SnS_(2)/Bi_(2)X_(3) heterostructure greatly improved the photoelectric response of a photoelectrochemical-type photodetector.The photocurrent densities in the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) and type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructure-based devices were more than one order of magnitude higher than those of SnS_(2),Bi_(2)Te_(3),and Bi_(2)Te_(3).The improved photoelectric properties of the SnS_(2)/Bi_(2)X_(3) heterostructures can be explained as follows:(i)the photoexcited electrons and holes are effectively separated in the heterostructures;(ii)the charge-transfer efficiency and carrier density at the interface between the SnS_(2)/Bi_(2)X_(3) heterostructures and the electrolyte are greatly improved;(iii)the formed heterostructures expand the light absorption range.The photoelectric performance was further enhanced by efficient light trapping in the upright SnS_(2).The photoelectric response is higher in the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) heterostructure than in the type-Ⅱ SnS_(2)/Bi_(2)Te_(3) heterostructure due to more efficient charge transportation at the type-Ⅰ SnS_(2)/Bi_(2)Te_(3) heterostructure/electrolyte interface.These results suggest that suitable type-Ⅰ and type-Ⅱ heterostructures can be developed for high-performance photodetectors and other optoelectronic devices.
基金the National Natural Science Foundation of China for the financial support(Nos.51971116,81771981,and 32001005)Shaanxi Provincial Science and Technology Department for financial support(No.2021JM-476)Shaanxi Provincial Administration of Traditional Chinese Medicine for financial support(No.20211-ZZ-JC007).
文摘Harsh photothermal temperatures(>50℃)caused heating damage to the normal tissues and induced thermal resistance in cancer cells,which significantly limited the safety and efficacy of photothermal therapy(PTT)in cancer treatment.Mild hyperthermia(<42℃)combined with chemotherapy might solve this issue.Herein,a novel transition metal dichalcogenides nanostructure,namely,Bi_(2)Se_(3)/MoSe_(2)nanosaucers(BMNSs),was designed to produce mild photo-hyperthermia(mPTT)and combined with chemotherapy to improve the overall antitumor efficacy.The BMNSs were constituted by Bi_(2)Se_(3)hexagonal nanoplates and enclosed with MoSe_(2)nanosheets evenly.While the MoSe_(2)moiety endowed the nanoplatform with excellent photothermal efficacy,the Bi_(2)Se_(3)substrates provided large specific surface area to anchor more doxorubicin(DOX)molecules as chemotherapeutic agent.Under the stimuli of mPTT/tumor acidic microenvironment,the tumor-specific drug release and the enhanced chemotherapy could be realized,showing impressive therapeutic outcomes against 4T1 cells.The synergetic therapeutic mechanism might be attributed to the mPTT induced cell membrane permeability,and interestingly,the expression of heat shock proteins 70 was not elevated obviously after the synergetic therapy,thus to avoid the tumor thermal resistance and further improve the therapeutic effect.The in vivo anti-tumoral performance of the BMNSs was further studied and complete tumor eradication was achieved without any recurrence and biotoxicity.Not only demonstrating a paradigm of high therapeutic efficacy of mild hyperthermia and synergistic chemotherapy for precise cancer therapy,our findings proved that the cancer therapeutic effect can be improved with minimal side effects through exquisite designing of the microstructures and the physiochemical properties of the nanoplatform.
