Chase-and-escape motion,which is a typical behavior between a predator and prey,is an important dynamics in animate systems.It has been concerned recently in optics aiming for achieving novel light steering and switch...Chase-and-escape motion,which is a typical behavior between a predator and prey,is an important dynamics in animate systems.It has been concerned recently in optics aiming for achieving novel light steering and switching functions.However,this optical counterpart can be realized in only one dimension because of the challenges in maintaining the chase-and-escape interaction.Herein,we report,both theoretically and experimentally,the optical predator-prey dynamics in two dimensions for the first time.Upon nonreciprocal interaction,two beams can form a localized or oblique spiral chase-and-escape motion,which persists owing to the mutual light confinement.Unusual optical phenomena are observed in these dynamics:the angular momentum is not conserved and the resulting transverse traveling motion can be opposite to the applied initial momentum and enhanced by increasing the internal light interactions.The results can inspire further fundamental studies by exploring analogous animate phenomena in optics that are potentially useful for developing optical intelligence functions.展开更多
In recent years,the development of ultrafast transmission electron microscopy(UTEM)has created new opportunities for studying dynamic processes at the nanoscale with unprecedented temporal resolution.~([1–3])The sign...In recent years,the development of ultrafast transmission electron microscopy(UTEM)has created new opportunities for studying dynamic processes at the nanoscale with unprecedented temporal resolution.~([1–3])The significant advances in femtosecond and even attosecond temporal resolution are achieved through the integration of the pump-probe principle with transmission electron microscopy(TEM).展开更多
It is very important to understand why a small amount of alkali metal doping in Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)solar cells can improve the conversion efficiency.In this work,Na-doped CZTSSe is prepared by a simple soluti...It is very important to understand why a small amount of alkali metal doping in Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)solar cells can improve the conversion efficiency.In this work,Na-doped CZTSSe is prepared by a simple solution method,and then the effects on the surface properties of the absorber layer,the buffer layer growth,and the modifications of the solar cell performance induced by the Na doping are studied.The surface of the absorber layer is more Cu-depletion and less roughness due to the Na doping.In addition,the contact angle of the surface increases because of Na doping.As a consequence,the thickness of the CdS buffer layer is significantly reduced and the optical losses in the CdS buffer layer are decreased.The difference of quasi-Fermi levels(EFn-EFp) increases with a small amount of Na doping in the CZTSSe solar cell,so that open circuit voltage(VOC) increased significantly.This work offers new insights into the effects of Na doping on CZTSSe via a solution-based approach and provides a deeper understanding of the origin of the efficiency improvement of Na-doped CZTSSe thin film solar cells.展开更多
The band alignment at the front interfaces is crucial for the performance of Sb_(2)Se_(3) solar cell with superstrate configuration.Herein,a Sn O_(2)/Ti O_(2) thin film,demonstrated beneficial for carrier transport in...The band alignment at the front interfaces is crucial for the performance of Sb_(2)Se_(3) solar cell with superstrate configuration.Herein,a Sn O_(2)/Ti O_(2) thin film,demonstrated beneficial for carrier transport in Sb_(2)Se_(3) device by the first-principle calculation and experiment,is proposed to reduce the parasitic absorption caused by CdS and optimize the band alignment of Sb_(2)Se_(3) solar cell.Thanks to the desirable transmittance of SnO_(2)/TiO_(2) layer,the Sb_(2)Se_(3) solar cell with SnO_(2)/TiO_(2)/(CdS-38 nm) electron transport layer performances better than (CdS-70 nm)/Sb_(2)Se_(3) solar cell.The optimized band alignment,the reduced interface defects and the decreased current leakage of Sb_(2)Se_(3) solar cell enable the short-circuit current density,fill factor,open-circuit voltage and efficiency of the Sb_(2)Se_(3) solar cell increase by 26.7%,112%,33.1%and 250%respectively when comparing with TiO_(2)/Sb_(2)Se_(3) solar cell without modification.Finally,an easily prepared Sn O_(2)/Ti O_(2)/CdS ETL is successfully applied on Sb_(2)Se_(3) solar cell by the first time and contributes to the best efficiency of 7.0%in this work,which is remarkable for Sb_(2)Se_(3) solar cells free of hole transporting materials and toxic CdCl_(2) treatment.This work is expected to provide a valuable reference for future ETL design and band alignment for Sb_(2)Se_(3) solar cell and other optoelectronic devices.展开更多
Cu2ZnSnS（e）4 （CZTS（e）） solar cells have attracted much attention due to the elemental abundance and the non- toxicity. However, the record efficiency of 12.6% for CuzZnSn（S,Se）4 （CZTSSe） solar cells is much ...Cu2ZnSnS（e）4 （CZTS（e）） solar cells have attracted much attention due to the elemental abundance and the non- toxicity. However, the record efficiency of 12.6% for CuzZnSn（S,Se）4 （CZTSSe） solar cells is much lower than that of Cu（In,Ga）See （CIGS） solar cells. One crucial reason is the recombination at interfaces. In recent years, large amount inves- tigations have been done to analyze the interfacial problems and improve the interfacial properties via a variety of methods. This paper gives a review of progresses on interfaces of CZTS（e） solar cells, including： （i） the band alignment optimization at buffer/CZTS（e） interface, （ii） tailoring the thickness of MoS（e）2 interfacial layers between CZTS（e） absorber and Mo back contact, （iii） the passivation of rear interface, （iv） the passivation of front interface, and （v） the etching of secondary phases.展开更多
Interaction with the substrate plays an essential role in determining the structure and electronic property of graphene supported by a surface.We observe a maze-like reconstruction pattern in graphene on flat copper f...Interaction with the substrate plays an essential role in determining the structure and electronic property of graphene supported by a surface.We observe a maze-like reconstruction pattern in graphene on flat copper foil.With functionalized scanning tunneling microscope tips,a triangular three-for-six structure of graphene and a mixed(2√2×√2)R45°reconstruction of a Cu(100)surface are separately visualized at the atomic scale.Substrate-induced changes in the structure and electronic property are further illustrated by micro-Raman spectroscopy and scanning tunneling spectroscopy.This finding suggests a new method to effectively induce partial sp3 hybridization in a single-layer graphene and therefore to tune its electronic property through interaction with the substrate.展开更多
The properties of Raman phonons are very important due to the fact that they can availably reflect some important physical information. An abnormal Raman peak is observed at about 558 cm-1 in In film composed of In/In...The properties of Raman phonons are very important due to the fact that they can availably reflect some important physical information. An abnormal Raman peak is observed at about 558 cm-1 in In film composed of In/InOx core-shell structured nanoparticles, and the phonon mode stays very stable when the temperature changes. Our results indicate that this Raman scattering is attributed to the existence of incomplete indium oxide in the oxide shell.展开更多
The molecular dynamic simulation of lithium niobate thin films deposited on silicon substrate is carried out by using the dissipative particle dynamics method. The simulation results show that the Si （111） surface i...The molecular dynamic simulation of lithium niobate thin films deposited on silicon substrate is carried out by using the dissipative particle dynamics method. The simulation results show that the Si （111） surface is more suitable for the growth of smooth LiNbO3 thin films compared to the Si（100） surface, and the optimal deposition temperature is around 873 K, which is consistent with the atomic force microscope results. In addition, the calculation molecular number is increased to take the electron spins and other molecular details into account.展开更多
基金supported by the National Key R&D Program of China(Grant No.2022YFA1404800)the National Natural Science Foundation of China(Grant Nos.12250009 and 62075105)the 111 Project in China(Grant No.B23045)。
文摘Chase-and-escape motion,which is a typical behavior between a predator and prey,is an important dynamics in animate systems.It has been concerned recently in optics aiming for achieving novel light steering and switching functions.However,this optical counterpart can be realized in only one dimension because of the challenges in maintaining the chase-and-escape interaction.Herein,we report,both theoretically and experimentally,the optical predator-prey dynamics in two dimensions for the first time.Upon nonreciprocal interaction,two beams can form a localized or oblique spiral chase-and-escape motion,which persists owing to the mutual light confinement.Unusual optical phenomena are observed in these dynamics:the angular momentum is not conserved and the resulting transverse traveling motion can be opposite to the applied initial momentum and enhanced by increasing the internal light interactions.The results can inspire further fundamental studies by exploring analogous animate phenomena in optics that are potentially useful for developing optical intelligence functions.
文摘In recent years,the development of ultrafast transmission electron microscopy(UTEM)has created new opportunities for studying dynamic processes at the nanoscale with unprecedented temporal resolution.~([1–3])The significant advances in femtosecond and even attosecond temporal resolution are achieved through the integration of the pump-probe principle with transmission electron microscopy(TEM).
基金supported by the National Key R&D Program of China(2019YFB1503500,2018YFB1500200,2018YEE0203400)the Natural Science Foundation of China(U1902218,11774187)the 111 project(B16027)。
文摘It is very important to understand why a small amount of alkali metal doping in Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)solar cells can improve the conversion efficiency.In this work,Na-doped CZTSSe is prepared by a simple solution method,and then the effects on the surface properties of the absorber layer,the buffer layer growth,and the modifications of the solar cell performance induced by the Na doping are studied.The surface of the absorber layer is more Cu-depletion and less roughness due to the Na doping.In addition,the contact angle of the surface increases because of Na doping.As a consequence,the thickness of the CdS buffer layer is significantly reduced and the optical losses in the CdS buffer layer are decreased.The difference of quasi-Fermi levels(EFn-EFp) increases with a small amount of Na doping in the CZTSSe solar cell,so that open circuit voltage(VOC) increased significantly.This work offers new insights into the effects of Na doping on CZTSSe via a solution-based approach and provides a deeper understanding of the origin of the efficiency improvement of Na-doped CZTSSe thin film solar cells.
基金supported by the National Key R&D Program of China(2019YFB1503500)the National Natural Science Foundation of China(U1902218,11774187)the Postgraduate Education Innovation Project of Tianjin,China(2021YJSB002)。
文摘The band alignment at the front interfaces is crucial for the performance of Sb_(2)Se_(3) solar cell with superstrate configuration.Herein,a Sn O_(2)/Ti O_(2) thin film,demonstrated beneficial for carrier transport in Sb_(2)Se_(3) device by the first-principle calculation and experiment,is proposed to reduce the parasitic absorption caused by CdS and optimize the band alignment of Sb_(2)Se_(3) solar cell.Thanks to the desirable transmittance of SnO_(2)/TiO_(2) layer,the Sb_(2)Se_(3) solar cell with SnO_(2)/TiO_(2)/(CdS-38 nm) electron transport layer performances better than (CdS-70 nm)/Sb_(2)Se_(3) solar cell.The optimized band alignment,the reduced interface defects and the decreased current leakage of Sb_(2)Se_(3) solar cell enable the short-circuit current density,fill factor,open-circuit voltage and efficiency of the Sb_(2)Se_(3) solar cell increase by 26.7%,112%,33.1%and 250%respectively when comparing with TiO_(2)/Sb_(2)Se_(3) solar cell without modification.Finally,an easily prepared Sn O_(2)/Ti O_(2)/CdS ETL is successfully applied on Sb_(2)Se_(3) solar cell by the first time and contributes to the best efficiency of 7.0%in this work,which is remarkable for Sb_(2)Se_(3) solar cells free of hole transporting materials and toxic CdCl_(2) treatment.This work is expected to provide a valuable reference for future ETL design and band alignment for Sb_(2)Se_(3) solar cell and other optoelectronic devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51572132,51372121,and 61674082)the Natural Science Foundation of Key Project of Tianjin City,China(Grant No.16JCZDJC30700)+1 种基金the Yang Fan Innovative and Entrepreneurial Research Team Project of China(Grant No.2014YT02N037)111 Project,China(Grant No.B16027)
文摘Cu2ZnSnS（e）4 （CZTS（e）） solar cells have attracted much attention due to the elemental abundance and the non- toxicity. However, the record efficiency of 12.6% for CuzZnSn（S,Se）4 （CZTSSe） solar cells is much lower than that of Cu（In,Ga）See （CIGS） solar cells. One crucial reason is the recombination at interfaces. In recent years, large amount inves- tigations have been done to analyze the interfacial problems and improve the interfacial properties via a variety of methods. This paper gives a review of progresses on interfaces of CZTS（e） solar cells, including： （i） the band alignment optimization at buffer/CZTS（e） interface, （ii） tailoring the thickness of MoS（e）2 interfacial layers between CZTS（e） absorber and Mo back contact, （iii） the passivation of rear interface, （iv） the passivation of front interface, and （v） the etching of secondary phases.
基金the National Natural Science Foundation of China under Grant Nos 11174347,61027011 and 10974245the National Basic Research Program of China under Grant No 2012CB933002+2 种基金the Chinese Academic of Sciences under Grant No 1731300500030the Robert a Welch Foundation(E-1728)the National Science Foundation(DMR-0907336,ECCS-1240510).
文摘Interaction with the substrate plays an essential role in determining the structure and electronic property of graphene supported by a surface.We observe a maze-like reconstruction pattern in graphene on flat copper foil.With functionalized scanning tunneling microscope tips,a triangular three-for-six structure of graphene and a mixed(2√2×√2)R45°reconstruction of a Cu(100)surface are separately visualized at the atomic scale.Substrate-induced changes in the structure and electronic property are further illustrated by micro-Raman spectroscopy and scanning tunneling spectroscopy.This finding suggests a new method to effectively induce partial sp3 hybridization in a single-layer graphene and therefore to tune its electronic property through interaction with the substrate.
基金Project supported by the National Natural Science Foundation of China （Grant Nos. 11374069 and 61006078）, the National Basic Research Program of China （Grant Nos. 2010CB934102 and 2010CB934101）, and the ＂Strategic Priority Research Program＂ of the Chinese Academy of Sciences （Grant No. XDA09020300）.
文摘The properties of Raman phonons are very important due to the fact that they can availably reflect some important physical information. An abnormal Raman peak is observed at about 558 cm-1 in In film composed of In/InOx core-shell structured nanoparticles, and the phonon mode stays very stable when the temperature changes. Our results indicate that this Raman scattering is attributed to the existence of incomplete indium oxide in the oxide shell.
基金supported by the National Basic Research Program of China(Grant No.2011CB922003)the International S&T Cooperation Program of China(Grant No.2013DFG52660)+1 种基金the Taishan Scholar Construction Project Special Fund,Chinathe Fundamental Research Funds for the Central Universities,China(Grant Nos.65030091 and 65010961)
文摘The molecular dynamic simulation of lithium niobate thin films deposited on silicon substrate is carried out by using the dissipative particle dynamics method. The simulation results show that the Si （111） surface is more suitable for the growth of smooth LiNbO3 thin films compared to the Si（100） surface, and the optimal deposition temperature is around 873 K, which is consistent with the atomic force microscope results. In addition, the calculation molecular number is increased to take the electron spins and other molecular details into account.
