Van der Waals(vdW)heterojunctions,with their unique electronic and optoelectronic properties,have become promising candidates for photodetector applications.Amplifying the contribution of the depletion region in vdW h...Van der Waals(vdW)heterojunctions,with their unique electronic and optoelectronic properties,have become promising candidates for photodetector applications.Amplifying the contribution of the depletion region in vdW heterojunction,which would enhance both of the collection efficiency and speed of the photogenerated carriers,presents an effective strategy for achieving high performance vdW heterojunction photodetectors.Herein,a fully depleted vdW heterojunction photodetector is built on two-dimensional(2D)semiconductor materials(GaTe and InSe)layered on a pattered bottom electrode in vertical structure,in which the generation and motion of carriers are exclusively achieved in the depletion region.Attributed to the intrinsic built-in electric field,the elimination of series resistance and the depletion region confinement of carriers,the as-fabricated photodetector exhibits prominent photovoltaic properties with a high open-circuit voltage of 0.465 V,as well as photoresponse characteristics with outstanding responsivity,detectivity and photoresponse speed of 63.7 A/W,3.88×10^(13)Jones,and 32.7 ms respectively.The overall performance of this fully depleted GaTe/InSe vdW heterojunctions photodetectors are ranking high among the top level of 2D materials based photodetectors.It indicates the device architecture can provide new opportunities for the fabrication of high-performance photodetectors.展开更多
Although photodetection based on two-dimensional(2D)van der Waals(vdWs)P-N heterojunction has attracted extensive attention recently,their low responsivity(R)due to the lack of carrier gain mechanism in reverse bias o...Although photodetection based on two-dimensional(2D)van der Waals(vdWs)P-N heterojunction has attracted extensive attention recently,their low responsivity(R)due to the lack of carrier gain mechanism in reverse bias or zero bias operation hinders their applications in advanced photodetection area.Here,a black phosphorus/rhodamine 6G/molybdenum disulfide(BP/R6G/MoS_(2))photodiode with high responsivity at reverse bias or zero bias has been achieved by using interfacial charge transfer of R6G molecules assembled between heterojunction layers.The formed vdWs interface achieves high performance photoresponse by efficiently separating the additional photogenerated electrons and holes generated by R6G molecules.The devices sensitized by the dye molecule R6G exhibit enhanced photodetection performance without sacrificing the photoresponse speed.Among them,the R increased by 14.8-20.4 times,and the specific detectivity(D^(*))increased by 24.9-34.4 times.The strategy based on interlayer assembly of dye molecules proposed here may pave a new way for realizing high-performance photodetection based on 2D vdWs heterojunctions with high responsivity and fast response speed.展开更多
Electrochemically producing formate by oxidizing methanol is a promising way to add value to methanol.Noble metal-based electrocatalysts,which have been extensively studied for the methanol oxidation reaction,can cata...Electrochemically producing formate by oxidizing methanol is a promising way to add value to methanol.Noble metal-based electrocatalysts,which have been extensively studied for the methanol oxidation reaction,can catalyze the complete oxidation of methanol to carbon dioxide,but not the mild oxidation to formate.As a result,exploring efficient and earth-abundant electrocatalysts for formate production from methanol is of interest.Herein,we present the electro-oxidation of methanol to formate,catalyzed by iron-substituted lanthanum cobaltite(LaCo_(1-x)Fe_(x)O_(3)).The Fe/Co ratio in the oxides greatly influences the activity and selectivity.This effect is attributed to the higher affinity of Fe and Co to the two reactants:CH3OH and OH,respectively.Because a balance between these affinities is favored,LaCo_(0.5)Fe_(0.5)O_(3) shows the highest formate production rate,at 24.5 mmol h^(-1) g_(oxide)^(-1),and a relatively high Faradaic efficiency of 44.4%in a series of(LaCo_(1-x)Fe_(x)O_(3))samples(x=0.00,0.25,0.50,0.75,1.00)at 1.6 V versus a reversible hydrogen electrode.展开更多
Neutron-transmutation doping(NTD)has been demonstrated for the first time in this work for substitutional introduction of tin(Sn)shallow donors into two-dimensional(2D)layered indium selenide(InSe)to manipulate electr...Neutron-transmutation doping(NTD)has been demonstrated for the first time in this work for substitutional introduction of tin(Sn)shallow donors into two-dimensional(2D)layered indium selenide(InSe)to manipulate electron transfer and charge carrier dynamics.Multidisciplinary study including density functional theory,transient optical absorption,and FET devices have been carried out to reveal that the field effect electron mobility of the fabricated phototransistor is increased 100-fold due to the smaller electron effective mass and longer electron life time in the Sn-doped InSe.The responsivity of the Sn-doped InSe based phototransistor is accordingly enhanced by about 50 times,being as high as 397 A/W.The results show that NTD is a highly effective and controllable doping method,possessing good compatibility with the semiconductor manufacturing process,even after device fabrication,and can be carried out without introducing any contamination,which is radically different from traditional doping methods.展开更多
基金supported by the State Key Research Development Program of China(Grant No.2019YFB2203503)National Natural Science Fund(Grant Nos.61875138,61961136001,62104153,62105211 and U1801254)+3 种基金Natural Science Foundation of Guangdong Province(2018B030306038 and 2020A1515110373)Science and Technology Projects in Guangzhou(no.202201000002)Science and Technology Innovation Commission of Shenzhen(JCYJ20180507182047316 and 20200805132016001)Natural Science Foundation of Jilin Province(Grant No.YDZJ202201ZYTS429)。
文摘Van der Waals(vdW)heterojunctions,with their unique electronic and optoelectronic properties,have become promising candidates for photodetector applications.Amplifying the contribution of the depletion region in vdW heterojunction,which would enhance both of the collection efficiency and speed of the photogenerated carriers,presents an effective strategy for achieving high performance vdW heterojunction photodetectors.Herein,a fully depleted vdW heterojunction photodetector is built on two-dimensional(2D)semiconductor materials(GaTe and InSe)layered on a pattered bottom electrode in vertical structure,in which the generation and motion of carriers are exclusively achieved in the depletion region.Attributed to the intrinsic built-in electric field,the elimination of series resistance and the depletion region confinement of carriers,the as-fabricated photodetector exhibits prominent photovoltaic properties with a high open-circuit voltage of 0.465 V,as well as photoresponse characteristics with outstanding responsivity,detectivity and photoresponse speed of 63.7 A/W,3.88×10^(13)Jones,and 32.7 ms respectively.The overall performance of this fully depleted GaTe/InSe vdW heterojunctions photodetectors are ranking high among the top level of 2D materials based photodetectors.It indicates the device architecture can provide new opportunities for the fabrication of high-performance photodetectors.
基金This work was supported by National Key Research and Development Project(No.2019YFB2203503)the National Natural Science Foundation of China(No.62105211)+8 种基金China Postdoctoral Science Foundation(Nos.2021M702242 and 2022T150431)Natural Science Foundation of Guangdong Province(Nos.2018B030306038 and 2020A1515110373)Guangdong Basic and Applied Basic Research Foundation(No.2022A1515010649)Science and Technology Projects in Guangzhou(No.202201000002)Science and Technology Innovation Commission of Shenzhen(Nos.JCYJ20180507182047316,20200805132016001,and JCYJ20200109105608771)Natural Science Foundation of Jilin Province(No.YDZJ202201ZYTS429)NTUT-SZU Joint Research Program(No.2021008)Authors acknowledge support and funding of King Khalid University through Research Center for Advanced Materials Science(RCAMS)(No.RCAMS/KKU/0010/21)The authors also acknowledge the Photonics Center of Shenzhen University for technical support.
文摘Although photodetection based on two-dimensional(2D)van der Waals(vdWs)P-N heterojunction has attracted extensive attention recently,their low responsivity(R)due to the lack of carrier gain mechanism in reverse bias or zero bias operation hinders their applications in advanced photodetection area.Here,a black phosphorus/rhodamine 6G/molybdenum disulfide(BP/R6G/MoS_(2))photodiode with high responsivity at reverse bias or zero bias has been achieved by using interfacial charge transfer of R6G molecules assembled between heterojunction layers.The formed vdWs interface achieves high performance photoresponse by efficiently separating the additional photogenerated electrons and holes generated by R6G molecules.The devices sensitized by the dye molecule R6G exhibit enhanced photodetection performance without sacrificing the photoresponse speed.Among them,the R increased by 14.8-20.4 times,and the specific detectivity(D^(*))increased by 24.9-34.4 times.The strategy based on interlayer assembly of dye molecules proposed here may pave a new way for realizing high-performance photodetection based on 2D vdWs heterojunctions with high responsivity and fast response speed.
基金This research was supported by the National Research Foundation,Prime Minister's Office,Singapore,under its Campus for Research Excellence and Technological Enterprise(CREATE)programThe work was partially supported by a Singapore Ministry of Education Tier 1 grant(2019-T1-002-125)and Tier 2 grant(MOE-T2EP10220-0001).
文摘Electrochemically producing formate by oxidizing methanol is a promising way to add value to methanol.Noble metal-based electrocatalysts,which have been extensively studied for the methanol oxidation reaction,can catalyze the complete oxidation of methanol to carbon dioxide,but not the mild oxidation to formate.As a result,exploring efficient and earth-abundant electrocatalysts for formate production from methanol is of interest.Herein,we present the electro-oxidation of methanol to formate,catalyzed by iron-substituted lanthanum cobaltite(LaCo_(1-x)Fe_(x)O_(3)).The Fe/Co ratio in the oxides greatly influences the activity and selectivity.This effect is attributed to the higher affinity of Fe and Co to the two reactants:CH3OH and OH,respectively.Because a balance between these affinities is favored,LaCo_(0.5)Fe_(0.5)O_(3) shows the highest formate production rate,at 24.5 mmol h^(-1) g_(oxide)^(-1),and a relatively high Faradaic efficiency of 44.4%in a series of(LaCo_(1-x)Fe_(x)O_(3))samples(x=0.00,0.25,0.50,0.75,1.00)at 1.6 V versus a reversible hydrogen electrode.
基金State Key Research Development Program of China(Grant No.2019YFB2203503)National Natural Science Fund(Grant Nos.61875138,61961136001,62104153,62105211 and U1801254)+2 种基金Natural Science Foundation of Guangdong Province(2018B030306038 and 2020A1515110373)Science and Technology Innovation Commission of Shenzhen(JCYJ20180507182047316 and 20200805132016001)Postdoctoral Science Foundation of China(No.2021M702237)。
文摘Neutron-transmutation doping(NTD)has been demonstrated for the first time in this work for substitutional introduction of tin(Sn)shallow donors into two-dimensional(2D)layered indium selenide(InSe)to manipulate electron transfer and charge carrier dynamics.Multidisciplinary study including density functional theory,transient optical absorption,and FET devices have been carried out to reveal that the field effect electron mobility of the fabricated phototransistor is increased 100-fold due to the smaller electron effective mass and longer electron life time in the Sn-doped InSe.The responsivity of the Sn-doped InSe based phototransistor is accordingly enhanced by about 50 times,being as high as 397 A/W.The results show that NTD is a highly effective and controllable doping method,possessing good compatibility with the semiconductor manufacturing process,even after device fabrication,and can be carried out without introducing any contamination,which is radically different from traditional doping methods.