Covalent organic frameworks（COFs） as an emerging class of porous materials have achieved remarkable progress in recent years.Their high surface area,low mass densities,highly ordered periodic structures,and ease of ...Covalent organic frameworks（COFs） as an emerging class of porous materials have achieved remarkable progress in recent years.Their high surface area,low mass densities,highly ordered periodic structures,and ease of functionalization make COFs exhibit superior potential in gas storage and separation,optoelectronic device and catalysis.This mini review gives a brief introduction of COFs and highlights their applications in electronic and optical fields.展开更多
Photocatalysis shows great promise in the field of solar energy conversion.One of the reasons for this is because it promotes the development of multi-field-coupled catalysis.In order to explore the principles of mult...Photocatalysis shows great promise in the field of solar energy conversion.One of the reasons for this is because it promotes the development of multi-field-coupled catalysis.In order to explore the principles of multi-field-coupled catalytic reactions,an in situ multi-field-coupled characterization technique is required.In this study,we obtained hydrogenated ST-01 TiO2 and observed enhanced catalytic activity by thermal coupled photocatalysis.In situ photoconductivity was employed to understand the activity enhancement.The effects of the reaction temperature,reaction atmosphere,and oxygen vacancy(Ov)on the photoconductivity of TiO2 were studied.After coupling thermal into photoconductivity measurement,highly active Ov-TiO2 displayed rapid decay of photoconductivity in a CO2 atmosphere and slow decay of photoconductivity in a N2 atmosphere.These phenomena revealed that photothermal coupling assisted the detrapping of electrons at the Ov surface and promoted electron transfer to CO2,which clearly explained the high photothermal catalytic activity of Ov-TiO2.This study demonstrated that photoconductivity is a useful tool to help understand photothermal catalytic phenomena.展开更多
利用镀膜技术和硅平面工艺在经过干氧氧化的硅衬底上制备一层钛铌酸锶(Sr NbxTi1-xO3)薄膜,然后制备成平面型薄膜光敏传感器。对钛铌酸锶薄膜的吸收光谱进行测定,得到其禁带宽度为2. 70 e V,对可见光有良好的敏感性。样品在稳定光照下,...利用镀膜技术和硅平面工艺在经过干氧氧化的硅衬底上制备一层钛铌酸锶(Sr NbxTi1-xO3)薄膜,然后制备成平面型薄膜光敏传感器。对钛铌酸锶薄膜的吸收光谱进行测定,得到其禁带宽度为2. 70 e V,对可见光有良好的敏感性。样品在稳定光照下,光电流随照度的增大而增大;温度对光敏特性影响很大,本传感器适用于稳定光照和室温下使用。展开更多
研究了一款光敏电阻型开关,用以实现光控有源频率选择表面(Optically Controlled Active Frequency Selective Surface, OCAFSS)。该开关在LED等光源激励下亮态阻值可小于20Ω,暗态值接近0.2 MΩ,并随着光源强度的变化阻值可调。通过对...研究了一款光敏电阻型开关,用以实现光控有源频率选择表面(Optically Controlled Active Frequency Selective Surface, OCAFSS)。该开关在LED等光源激励下亮态阻值可小于20Ω,暗态值接近0.2 MΩ,并随着光源强度的变化阻值可调。通过对光敏电阻内部结构的分析以及借鉴硅片型光控微波开关的建模经验,使用CST等电磁仿真软件对该开关进行了建模与仿真。经实物加工和测试,所得测试结果与仿真结果一致,显示出该光敏电阻在频段0.1~1 GHz可切换亮/暗状态,其S21参数分别为-3 dB以上和-10 dB以下,对应的传输信号可以通过或被阻挡;但随着频率的升高,开关效果不再明显,当频率大于2 GHz以后,亮暗态S21均在-7 dB以上,不再具备开关性能。对该光敏电阻的开关特性研究表明,可将其使用于特定频段OCAFSS。为验证这一结论的正确性,我们制作了一款该使用频段的吸波型OCAFSS,最终测试结果与预期值符合。展开更多
Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells(PSCs)with widely tunable bandgap have achieved rapid growth in power conversion efficiency,which exceeds 25%now.It is deliberated ...Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells(PSCs)with widely tunable bandgap have achieved rapid growth in power conversion efficiency,which exceeds 25%now.It is deliberated that if a semitransparent solar cell made of wider bandgap materials was placed on top of a narrow bandgap materials-based solar cell such as a silicon solar cell,with proper optical and electrical arrangements,the resultant tandem device consisting of two subcells could more effectively utilize the solar spectrum than a single junction solar cell.In a perovskite/silicon tandem solar cell(PSTSC),a semitransparent PSC with a wider bandgap is placed on top of a narrow bandgap silicon solar cell.The PSC efficiently harvests the higher energy photons in the ultraviolet and visible regions of the solar spectrum while the silicon solar cell can convert the photons of the infrared region to power.The PSTSC is proposed as a potential candidate to overcome the Shockley-Queisser limit of single-junction silicon solar cells.Though the theoretical limit of a PSTSC is calculated as~42%,its actual efficiency achieved until now is less than 30%.Therefore,a great scope of research exists in improving the efficiency of PSTSCs.Current issues of stability and upscaling of the device in PSCs are also a matter of concern for PSTSCs.A tandem device consists of multiple parts,and different configurations can be applied,thus tuning the architecture of the device.Altering various parts may result in significant changes in the efficiency of the device.In this review,competing architectures of otherwise comparable devices are compared in terms of photovoltaic properties.Thus,future directions to improve the efficiency of the device based on architecture design are proposed herein.In particular,the influence of the polarity of PSCs and the surface morphology of silicon solar cells(both front and rear)on determining the properties of the PSTSC are discussed.展开更多
Black phosphorus quantum dots(BPQDs)are synthesized and combined with graphene sheet.The fabricated BPQDs/graphene devices are capable of detecting visible and near infrared radiation.The adsorption efect of BPQDs in ...Black phosphorus quantum dots(BPQDs)are synthesized and combined with graphene sheet.The fabricated BPQDs/graphene devices are capable of detecting visible and near infrared radiation.The adsorption efect of BPQDs in graphene is clarifed by the relationship of the photocurrent and the shift of the Dirac point with diferent substrate.The Dirac point moves toward a neutral point under illumination with both SiO_(2)/Si and Si(3)N_(4)/Si substrates,indicating an anti-doped feature of photo-excitation.To our knowledge,this provides the frst observation of photoresist induced photocurrent in such systems.Without the infuence of the photoresist the device can respond to infrared light up to 980 nm wavelength in vacuum in a cryostat,in which the photocurrent is positive and photoconduction efect is believed to dominate the photocurrent.Finally,the adsorption efect is modeled using a frst-principle method to give a picture of charge transfer and orbital contribution in the interaction of phosphorus atoms and single-layer graphene.展开更多
基金the 973 Program(No.2013CB834704)the National Natural Science Foundation of China(Nos.21471018,21201018,21404010)1000 Plan (Youth) for financial support
文摘Covalent organic frameworks（COFs） as an emerging class of porous materials have achieved remarkable progress in recent years.Their high surface area,low mass densities,highly ordered periodic structures,and ease of functionalization make COFs exhibit superior potential in gas storage and separation,optoelectronic device and catalysis.This mini review gives a brief introduction of COFs and highlights their applications in electronic and optical fields.
基金supported by the Natural Science Foundation of China(51072032,51372036,51102001)the Key Project of Chinese Ministry of Education(113020A)+1 种基金the 111 project(B13013)Jilin Province Science and Technology Development Plan(20180101175JC,20160520170JH)~~
文摘Photocatalysis shows great promise in the field of solar energy conversion.One of the reasons for this is because it promotes the development of multi-field-coupled catalysis.In order to explore the principles of multi-field-coupled catalytic reactions,an in situ multi-field-coupled characterization technique is required.In this study,we obtained hydrogenated ST-01 TiO2 and observed enhanced catalytic activity by thermal coupled photocatalysis.In situ photoconductivity was employed to understand the activity enhancement.The effects of the reaction temperature,reaction atmosphere,and oxygen vacancy(Ov)on the photoconductivity of TiO2 were studied.After coupling thermal into photoconductivity measurement,highly active Ov-TiO2 displayed rapid decay of photoconductivity in a CO2 atmosphere and slow decay of photoconductivity in a N2 atmosphere.These phenomena revealed that photothermal coupling assisted the detrapping of electrons at the Ov surface and promoted electron transfer to CO2,which clearly explained the high photothermal catalytic activity of Ov-TiO2.This study demonstrated that photoconductivity is a useful tool to help understand photothermal catalytic phenomena.
文摘利用镀膜技术和硅平面工艺在经过干氧氧化的硅衬底上制备一层钛铌酸锶(Sr NbxTi1-xO3)薄膜,然后制备成平面型薄膜光敏传感器。对钛铌酸锶薄膜的吸收光谱进行测定,得到其禁带宽度为2. 70 e V,对可见光有良好的敏感性。样品在稳定光照下,光电流随照度的增大而增大;温度对光敏特性影响很大,本传感器适用于稳定光照和室温下使用。
基金supported by the National Key Research and Development Program of China(Grant No.2018YFB1500103)the Joint Funds of the National Natural Science Foundation of China(Grant No.U21A2072)+7 种基金the Natural Science Foundation of Tianjin(Grant No.20JCQNJC02070)China Postdoctoral Science Foundation(Grant No.2020T130317)the Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China(Grant No.B16027)Tianjin Science and Technology Project(Grant No.18ZXJMTG00220)the Key R&D Program of Hebei Province(Grant No.19214301D)the Haihe Laboratory of Sustainable Chemical Transformationsthe Fundamental Research Funds for the Central UniversitiesNankai University。
文摘Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells(PSCs)with widely tunable bandgap have achieved rapid growth in power conversion efficiency,which exceeds 25%now.It is deliberated that if a semitransparent solar cell made of wider bandgap materials was placed on top of a narrow bandgap materials-based solar cell such as a silicon solar cell,with proper optical and electrical arrangements,the resultant tandem device consisting of two subcells could more effectively utilize the solar spectrum than a single junction solar cell.In a perovskite/silicon tandem solar cell(PSTSC),a semitransparent PSC with a wider bandgap is placed on top of a narrow bandgap silicon solar cell.The PSC efficiently harvests the higher energy photons in the ultraviolet and visible regions of the solar spectrum while the silicon solar cell can convert the photons of the infrared region to power.The PSTSC is proposed as a potential candidate to overcome the Shockley-Queisser limit of single-junction silicon solar cells.Though the theoretical limit of a PSTSC is calculated as~42%,its actual efficiency achieved until now is less than 30%.Therefore,a great scope of research exists in improving the efficiency of PSTSCs.Current issues of stability and upscaling of the device in PSCs are also a matter of concern for PSTSCs.A tandem device consists of multiple parts,and different configurations can be applied,thus tuning the architecture of the device.Altering various parts may result in significant changes in the efficiency of the device.In this review,competing architectures of otherwise comparable devices are compared in terms of photovoltaic properties.Thus,future directions to improve the efficiency of the device based on architecture design are proposed herein.In particular,the influence of the polarity of PSCs and the surface morphology of silicon solar cells(both front and rear)on determining the properties of the PSTSC are discussed.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.61922022,62175026,62171094,and 62104026)。
文摘Black phosphorus quantum dots(BPQDs)are synthesized and combined with graphene sheet.The fabricated BPQDs/graphene devices are capable of detecting visible and near infrared radiation.The adsorption efect of BPQDs in graphene is clarifed by the relationship of the photocurrent and the shift of the Dirac point with diferent substrate.The Dirac point moves toward a neutral point under illumination with both SiO_(2)/Si and Si(3)N_(4)/Si substrates,indicating an anti-doped feature of photo-excitation.To our knowledge,this provides the frst observation of photoresist induced photocurrent in such systems.Without the infuence of the photoresist the device can respond to infrared light up to 980 nm wavelength in vacuum in a cryostat,in which the photocurrent is positive and photoconduction efect is believed to dominate the photocurrent.Finally,the adsorption efect is modeled using a frst-principle method to give a picture of charge transfer and orbital contribution in the interaction of phosphorus atoms and single-layer graphene.
