The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied...The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.展开更多
Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and str...Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and structural stability that limit the performance.The core-shell semiconductorgraphene(CSSG)nanoarchitectures may address these issues due to their unique structures with exceptional physical and chemical properties.This review explores recent advances of the CSSG nanoarchitectures in the photocatalytic performance.It starts with the classification of the CSSG nanoarchitectures by the dimensionality.Then,the construction methods under internal and external driving forces were introduced and compared with each other.Afterward,the physicochemical properties and photocatalytic applications of these nanoarchitectures were discussed,with a focus on their role in photocatalysis.It ends with a summary and some perspectives on future development of the CSSG nanoarchitectures toward highly efficient photocatalysts with extensive application.By harnessing the synergistic capabilities of the CSSG architectures,we aim to address pressing environmental and energy challenges and drive scientific progress in these fields.展开更多
The doping of ZnO has attracted lots of attention because it is an important way to tune the properties of ZnO.Postdoping after growth is one of the efficient strategies.Here,we report a unique approach to successfull...The doping of ZnO has attracted lots of attention because it is an important way to tune the properties of ZnO.Postdoping after growth is one of the efficient strategies.Here,we report a unique approach to successfully dope the single crystalline ZnO with Ag by the laser-induced method,which can effectively further post-treat grown samples.Magnetron sputtering was used to coat the Ag film with a thickness of about 50 nm on the single crystalline ZnO.Neodymium-doped yttrium aluminum garnet(Nd:YAG)laser was chosen to irradiate the Ag-capped ZnO samples,followed by annealing at700℃for two hours to form ZnO:Ag.The three-dimensional(3D)information of the elemental distribution of Ag in ZnO was obtained through time-of-flight secondary ion mass spectrometry(TOF-SIMS).TOF-SIMS and core-level x-ray photoelectron spectroscopy(XPS)demonstrated that the Ag impurities could be effectively doped into single crystalline ZnO samples as deep as several hundred nanometers.Obvious broadening of core level XPS profiles of Ag from the surface to depths of hundred nms was observed,indicating the variance of chemical state changes in laser-induced Ag-doped ZnO.Interesting features of electronic mixing states were detected in the valence band XPS of ZnO:Ag,suggesting the strong coupling or interaction of Ag and ZnO in the sample rather than their simple mixture.The Ag-doped ZnO also showed a narrower bandgap and a decrease in thermal diffusion coefficient compared to the pure ZnO,which would be beneficial to thermoelectric performance.展开更多
Deep-ultraviolet(DUV)disinfection technology provides an expeditious and efficient way to suppress the transmission of coronavirus disease 2019(COVID-19).However,the influences of viral variants(Delta and Omicron)and ...Deep-ultraviolet(DUV)disinfection technology provides an expeditious and efficient way to suppress the transmission of coronavirus disease 2019(COVID-19).However,the influences of viral variants(Delta and Omicron)and low temperatures on the DUV virucidal efficacy are still unknown.Here,we developed a reliable and uniform planar light source comprised of 275-nm light-emitting diodes(LEDs)to investigate the effects of these two unknown factors and delineated the principle behind different disinfection performances.We found the lethal effect of DUV at the same radiation dose was reduced by the cryogenic environment,and a negative-U large-relaxation model was used to explain the difference in view of the photoelectronic nature.The chances were higher in the cryogenic environment for the capture of excited electrons within active genetic molecules back to the initial photo-ionised positions.Additionally,the variant of Omicron required a significantly higher DUV dose to achieve the same virucidal efficacy,and this was thanks to the genetic and proteinic characteristics of the Omicron.The findings in this study are important for human society using DUV disinfection in cold conditions(e.g.,the food cold chain logistics and the open air in winter),and the relevant DUV disinfection suggestion against COVID-19 is provided.展开更多
To deal with the invalidation of commonly employed series model and parallel model in capacitance-voltage(C-V)characterization of organic thin films when current injection is significant,a three-element equivalent cir...To deal with the invalidation of commonly employed series model and parallel model in capacitance-voltage(C-V)characterization of organic thin films when current injection is significant,a three-element equivalent circuit model is proposed.On this basis,the expression of real capacitance in consideration of current injection is theoretically derived by small-signal analysis method.The validity of the proposed equivalent circuit and theoretical expression are verified by a simulating circuit consisting of a capacitor,a diode,and a resistor.Moreover,the accurate C-V characteristic of an organic thin film device is obtained via theoretical correction of the experimental measuring result,and the real capacitance is 35.7%higher than the directly measured capacitance at 5-V bias in the parallel mode.This work strongly demonstrates the necessity to consider current injection in C-V measurement and provides a strategy for accurate C-V characterization experimentally.展开更多
By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input ...By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input and output of SGM is established based on systematic design point. Meanwhile, the mathematical expression for SGM is deduced by integrating matrix theory and graph theory; thus, the topological characteristics of the kinematic structure of SGM can be converted into a matrix model, and the topological design problem of SGM into a matrix operation problem. In addition, a brief discussion about the measures for identification of isomorphism of the graph mode is made.展开更多
基金support from the National Key Research and Development Program of China(No.2022YFE0137400)the National Natural Science Foundation of China(Grant No.62274040).
文摘The past decade has witnessed the rapid increasement in power conversion efficiency of perovskite solar cells(PSCs).However,serious ion migration hampers their operational stability.Although dopants composed of varied cations and anions are introduced into perovskite to suppress ion migration,the impact of cations or anions is not individually explored,which hinders the evaluation of different cations and further application of doping strategy.Here we report that a special group of sulfonic anions(like CF_(3)SO_(3)^(-))successfully introduce alkaline earth ions(like Ca^(2+))into perovskite lattice compared to its halide counterparts.Furthermore,with effective crystallization regulation and defect passivation of sulfonic anions,perovskite with Ca(CF_(3)SO_(3))_(2)shows reduced PbI2 residue and metallic Pb0 defects;thereby,corresponding PSCs show an enhanced PCE of 24.95%.Finally by comparing the properties of perovskite with Ca(CF_(3)SO_(3))_(2)and FACF_(3)SO_(3),we found that doped Ca^(2+)significantly suppressed halide migration with an activation energy of 1.246 eV which accounts for the improved operational stability of Ca(CF_(3)SO_(3))_(2-)doped PSCs,while no obvious impact of Ca^(2+)on trap density is observed.Combining the benefits of cations and anions,this study presents an effective method to decouple the effects of cations and anions and fabricate efficient and stable PSCs.
基金supported by the National Natural Science Foundation of China(61974125)the Open Innovation Fund for undergraduate students of Xiamen University(KFJJ-202411).
文摘Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and structural stability that limit the performance.The core-shell semiconductorgraphene(CSSG)nanoarchitectures may address these issues due to their unique structures with exceptional physical and chemical properties.This review explores recent advances of the CSSG nanoarchitectures in the photocatalytic performance.It starts with the classification of the CSSG nanoarchitectures by the dimensionality.Then,the construction methods under internal and external driving forces were introduced and compared with each other.Afterward,the physicochemical properties and photocatalytic applications of these nanoarchitectures were discussed,with a focus on their role in photocatalysis.It ends with a summary and some perspectives on future development of the CSSG nanoarchitectures toward highly efficient photocatalysts with extensive application.By harnessing the synergistic capabilities of the CSSG architectures,we aim to address pressing environmental and energy challenges and drive scientific progress in these fields.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFB3605403)。
文摘The doping of ZnO has attracted lots of attention because it is an important way to tune the properties of ZnO.Postdoping after growth is one of the efficient strategies.Here,we report a unique approach to successfully dope the single crystalline ZnO with Ag by the laser-induced method,which can effectively further post-treat grown samples.Magnetron sputtering was used to coat the Ag film with a thickness of about 50 nm on the single crystalline ZnO.Neodymium-doped yttrium aluminum garnet(Nd:YAG)laser was chosen to irradiate the Ag-capped ZnO samples,followed by annealing at700℃for two hours to form ZnO:Ag.The three-dimensional(3D)information of the elemental distribution of Ag in ZnO was obtained through time-of-flight secondary ion mass spectrometry(TOF-SIMS).TOF-SIMS and core-level x-ray photoelectron spectroscopy(XPS)demonstrated that the Ag impurities could be effectively doped into single crystalline ZnO samples as deep as several hundred nanometers.Obvious broadening of core level XPS profiles of Ag from the surface to depths of hundred nms was observed,indicating the variance of chemical state changes in laser-induced Ag-doped ZnO.Interesting features of electronic mixing states were detected in the valence band XPS of ZnO:Ag,suggesting the strong coupling or interaction of Ag and ZnO in the sample rather than their simple mixture.The Ag-doped ZnO also showed a narrower bandgap and a decrease in thermal diffusion coefficient compared to the pure ZnO,which would be beneficial to thermoelectric performance.
基金supported by the National Key R&D Program of China(2022YFB3605002)the Key Scientific and Technological Program of Xiamen(3502Z20211002).
文摘Deep-ultraviolet(DUV)disinfection technology provides an expeditious and efficient way to suppress the transmission of coronavirus disease 2019(COVID-19).However,the influences of viral variants(Delta and Omicron)and low temperatures on the DUV virucidal efficacy are still unknown.Here,we developed a reliable and uniform planar light source comprised of 275-nm light-emitting diodes(LEDs)to investigate the effects of these two unknown factors and delineated the principle behind different disinfection performances.We found the lethal effect of DUV at the same radiation dose was reduced by the cryogenic environment,and a negative-U large-relaxation model was used to explain the difference in view of the photoelectronic nature.The chances were higher in the cryogenic environment for the capture of excited electrons within active genetic molecules back to the initial photo-ionised positions.Additionally,the variant of Omicron required a significantly higher DUV dose to achieve the same virucidal efficacy,and this was thanks to the genetic and proteinic characteristics of the Omicron.The findings in this study are important for human society using DUV disinfection in cold conditions(e.g.,the food cold chain logistics and the open air in winter),and the relevant DUV disinfection suggestion against COVID-19 is provided.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11874007 and 12074076).
文摘To deal with the invalidation of commonly employed series model and parallel model in capacitance-voltage(C-V)characterization of organic thin films when current injection is significant,a three-element equivalent circuit model is proposed.On this basis,the expression of real capacitance in consideration of current injection is theoretically derived by small-signal analysis method.The validity of the proposed equivalent circuit and theoretical expression are verified by a simulating circuit consisting of a capacitor,a diode,and a resistor.Moreover,the accurate C-V characteristic of an organic thin film device is obtained via theoretical correction of the experimental measuring result,and the real capacitance is 35.7%higher than the directly measured capacitance at 5-V bias in the parallel mode.This work strongly demonstrates the necessity to consider current injection in C-V measurement and provides a strategy for accurate C-V characterization experimentally.
文摘By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input and output of SGM is established based on systematic design point. Meanwhile, the mathematical expression for SGM is deduced by integrating matrix theory and graph theory; thus, the topological characteristics of the kinematic structure of SGM can be converted into a matrix model, and the topological design problem of SGM into a matrix operation problem. In addition, a brief discussion about the measures for identification of isomorphism of the graph mode is made.
