The coupling of charge carrier and phonon transport limits the application of Ag_(2)Se as a low-toxic near-room-temperature thermoelectric material.Strategies that reduce the thermal conductivity via enhanc-ing the ph...The coupling of charge carrier and phonon transport limits the application of Ag_(2)Se as a low-toxic near-room-temperature thermoelectric material.Strategies that reduce the thermal conductivity via enhanc-ing the phonon scattering usually lead to reduced carrier mobility due to high grain boundary potential barrier.In this study,we developed a cell-membrane-mimic grain boundary engineering strategy for de-coupling the charge carrier and phonon scattering through decorating high-dielectric-constant rutile TiO_(2) at Ag_(2)Se grain boundaries to enable the charge carrier/phonon selective permeability.The nano-sized TiO_(2) with high dielectric permittivity can secure the charge carrier transport by shielding the interfacial Coulomb potential to lower the energy barrier of grain boundaries,rendering an enhanced power factor.Additionally,benefited from the enhanced phonon scattering by TiO_(2) nanoparticles,a significantly de-creased lattice thermal conductivity of~0.20 W m^(-1) K^(-1) and a high zT of~0.97 at 390 K are obtained in the Ag_(2)Se-based nanocomposites.This work demonstrates that such cell-membrane-mimic grain bound-ary engineering strategy may shed light on developing high-performance thermoelectric materials.展开更多
Although silver(Ag) substitution offers several benefits in eliminating bulk defects and facilitating interface type inversion for Cu2ZnSn(S,Se)4(CZTSSe) photovoltaic(PV) technology, its further development is still h...Although silver(Ag) substitution offers several benefits in eliminating bulk defects and facilitating interface type inversion for Cu2ZnSn(S,Se)4(CZTSSe) photovoltaic(PV) technology, its further development is still hindered by the fairly low electrical conductivity due to the significant decrease of acceptors amount.In this work, a versatile Li–Ag co-doping strategy is demonstrated to mitigate the poor electrical conductivity arising from Ag through direct incorporating Li via postdeposition treatment(PDT) on top of the Ag-substituted CZTSSe absorber. Depth characterizations demonstrate that Li incorporation increases ptype carrier concentration, improves the carrier collection within the bulk, reduces the defects energy level as well as inverts the electric field polarity at grain boundaries(GBs) for Ag-substituted CZTSSe system. Benefiting from this lithium-assisted complex engineering of electrical performance both in grain interior(GI) and GBs, the power conversion efficiency(PCE) is finally increased from 9.21% to 10.29%. This systematic study represents an effective way to overcome the challenges encountered in Ag substitution,and these findings support a new aspect that the synergistic effects of double cation dopant will further pave the way for the development of high efficiency kesterite PV technology.展开更多
In this work,Ag/Ag_(2)Se composite films with excellent thermoelectric(TE)properties and flexibility are prepared based on a simple one-pot method.By adjusting the nominal ratios of Ag/Se,an optimal Ag/Ag_(2)Se compos...In this work,Ag/Ag_(2)Se composite films with excellent thermoelectric(TE)properties and flexibility are prepared based on a simple one-pot method.By adjusting the nominal ratios of Ag/Se,an optimal Ag/Ag_(2)Se composite film shows a large power factor of~2275 μW m^(-1) K^(-2) at 300 K.Such an outstand-ing TE performance of the composite film is due to the unique microstructure and the synergistic effect between the Ag and Ag_(2)Se.Meanwhile,the composite film also shows outstanding flexibility(~91.8%of the initial electrical conductivity is maintained,and the S is unchanged after 1500 bending cycles with a bending radius of 4 mm).Furthermore,a 4-leg flexible TE generator assembled with the optimal film produces a voltage of 14.06 mV and 4.96 μW at a temperature difference of 30.4 K.This work provides a new inspiration for the preparation of flexible Ag_(2)Se-based films with excellent TE performance near room temperature.展开更多
High-quality II-VI semiconductor ZnSe nanowires were facilely prepared in the oleic acid and oleylamine mixed solution at low temperatures of 130°C-200°C through an Ag2Se-catalyzed growth mechanism. Oleylami...High-quality II-VI semiconductor ZnSe nanowires were facilely prepared in the oleic acid and oleylamine mixed solution at low temperatures of 130°C-200°C through an Ag2Se-catalyzed growth mechanism. Oleylamine served as an effective reducing agent and a surfactant in the synthesis. Many of the resultant nanowires were terminated by an Ag2Se catalyst particle at one of their ends, confirming that the nanowire growth followed a catalytic mechanism. The crystal structure of Ag2Se catalyst was examined, which exhibited a metastable tetragonal phase, not the common orthorhombic phase. Meanwhile, the optical properties of as-synthesized ZnSe nanowire solid powder were evaluated by the UV-Visible diffuse reflectance and photoluminescence spectroscopy and a significant blue shift was observed compared to the bulk ZnSe with a band gap of 2.7 eV. This work would provide an alternative and effective catalytic route for the preparation of one-dimensional (1D) nanostructures of ZnSe and other metal selenides.展开更多
The environmentally friendly Cu_(2)ZnSn(S,Se)_(4)(CZTSSe) compounds are promising direct bandgap materials for application in thin film solar cells, but the spontaneous surface defects disordering would lead to large ...The environmentally friendly Cu_(2)ZnSn(S,Se)_(4)(CZTSSe) compounds are promising direct bandgap materials for application in thin film solar cells, but the spontaneous surface defects disordering would lead to large open-circuit voltage deficit(V_(oc,deficit)) and significantly limit kesterite photovoltaics performance,primarily arising from the generated more recombination centers and insufficient p to n conversion at p-n junction. Herein, we establish a surface defects ordering structure in CZTSSe system via local substitution of Cu by Ag to suppress disordered Cu_(Zn) defects and generate benign n-type Zn_(Ag) donors. Taking advantage of the decreased annealing temperature of Ag F post deposition treatment(PDT), the high concentration of Ag incorporated into surface absorber facilitates the formation of surface ordered defect environment similar to that of efficient CIGS PV. The manipulation of highly doped surface structure could effectively reduce recombination centers, increase depletion region width and enlarge the band bending near p-n junction. As a result, the Ag F-PDT device finally achieves maximum efficiency of 12.34% with enhanced V_(oc) of 0.496 V. These results offer a new solution route in surface defects and energy-level engineering, and open the way to build up high quality p-n junction for future development of kesterite technology.展开更多
As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities...As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities and long lifespan.However,the lack of high-rate anodes that can match the high-power-density cathode hinders the commercial application of SICs.In this work,heterostructured Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite is pre-pared by chemical vapor deposition(CVD)method and investigated as the anode for SICs.Through heterointerface manipulation,Fe/FeSe_(2)/Fe_(3)Se_(4)demonstrates better sodium ion storage performances than the pure FeSe_(2)and FeSe_(2)/Fe_(3)Se_(4).It can deliver a specific capacity of 484.8 mAh·g^(-1)after 100 cycles at 0.5 A·g^(-1),as well as a good capacity retention.The excellent performance of Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components,where FeSe_(2)and Fe_(3)Se_(4) are responsible for offering a high capacity and metallic Fe can server as mini-current collectors,effec-tively accelerating the electron and charge transfer behavior.Meanwhile,the heterointerface significantly facilitates the sodium ion fast transport,and retards the structural variation during cycling.FeSe-1000//activated carbon(AC)SIC affords a high energy density of 112 Wh·kg^(-1)at 107.5 W·kg^(-1),its power density can achieve 10,750 W·kg^(-1)with remained energy density of 44.2 Wh·kg^(-1),as well as an outstanding cycling stability,demonstrating this effective heterointerface engineered anode strategy for high-performance SICs.展开更多
Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass pl...Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass plate (CGP) substrate by the decomposition of polyethylene glycol (PEG) mixing in titanium hydroxide sol at 450℃. Then,the TiO2/Ag2Se interface composite film was fabricated by interface reaction of AgNO3 with NaSeSO3 on the activated surface of porous TiO2 film. The results of SEM and XRD analyses indicated that the porous TiO2 layer was made up of the anatase crystal,and the Ag2Se layer was made up of congregative small particles that have low-temperature α-phase structure. Due to its efficient charge separation for the photo-induced electron-hole pairs,the TiO2/Ag2Se interface composite film as-prepared has good photovoltaic property and high photocurrent response for visible light,which have been confirmed by the photoelectrochemical measurements.展开更多
Engineering the electronic properties of catalysts to target intermediate adsorption energy as well as harvest high selectivity represents a promising strategy to design advanced electrocatalysts for efficient CO_(2)e...Engineering the electronic properties of catalysts to target intermediate adsorption energy as well as harvest high selectivity represents a promising strategy to design advanced electrocatalysts for efficient CO_(2)electroreduction.Herein,a synergistical tuning on the electronic structure of the Cd Se nanorods is proposed for boosting electrochemical reduction of CO_(2).The synergy of Ag doping coupled with Se vacancies tuned the electronic structure of the CdSe nanorods,which shows the metalloid characterization and thereby the accelerated electron transfer of CO_(2)electroreduction.Operando synchrotron radiation Fourier transform infrared spectroscopy and theoretical simulation revealed that the Ag doping and Se vacancies accelerated the CO_(2)activation process and lowered the energy barrier for the conversion from CO_(2)to;COOH;as a result,the performance of CO_(2)electroreduction was enhanced.The as-obtained metalloid Ag-doped CdSe nanorods exhibited a 2.7-fold increment in current density and 1.9-fold Faradaic efficiency of CO compared with the pristine CdSe nanorod.展开更多
基金National Natural Science Foundation of China(Nos.12074015,52002254,52272160)Sichuan Science and Technology Program(No.2023YFG0220)+3 种基金Fundamental Research Funds for the Central Universities(No.YJ202242)Research Funding from West China School/Hospital of Stomatology Sichuan University,(No.QDJF2022-2)State Key Laboratory for Mechanical Behavior of Materials(No.20232509)fund of the State Key Laboratory of Solidifica-tion Processing in NPU(No.SKLSP202315).
文摘The coupling of charge carrier and phonon transport limits the application of Ag_(2)Se as a low-toxic near-room-temperature thermoelectric material.Strategies that reduce the thermal conductivity via enhanc-ing the phonon scattering usually lead to reduced carrier mobility due to high grain boundary potential barrier.In this study,we developed a cell-membrane-mimic grain boundary engineering strategy for de-coupling the charge carrier and phonon scattering through decorating high-dielectric-constant rutile TiO_(2) at Ag_(2)Se grain boundaries to enable the charge carrier/phonon selective permeability.The nano-sized TiO_(2) with high dielectric permittivity can secure the charge carrier transport by shielding the interfacial Coulomb potential to lower the energy barrier of grain boundaries,rendering an enhanced power factor.Additionally,benefited from the enhanced phonon scattering by TiO_(2) nanoparticles,a significantly de-creased lattice thermal conductivity of~0.20 W m^(-1) K^(-1) and a high zT of~0.97 at 390 K are obtained in the Ag_(2)Se-based nanocomposites.This work demonstrates that such cell-membrane-mimic grain bound-ary engineering strategy may shed light on developing high-performance thermoelectric materials.
基金the National Natural Science Foundation of China(61874159,61974173,51702085,51802081 and 21603058)the Joint Talent Cultivation Funds of NSFC-HN(U1704151)the Science and Technology Innovation Talents in Universities of Henan Province(18HASTIT016)。
文摘Although silver(Ag) substitution offers several benefits in eliminating bulk defects and facilitating interface type inversion for Cu2ZnSn(S,Se)4(CZTSSe) photovoltaic(PV) technology, its further development is still hindered by the fairly low electrical conductivity due to the significant decrease of acceptors amount.In this work, a versatile Li–Ag co-doping strategy is demonstrated to mitigate the poor electrical conductivity arising from Ag through direct incorporating Li via postdeposition treatment(PDT) on top of the Ag-substituted CZTSSe absorber. Depth characterizations demonstrate that Li incorporation increases ptype carrier concentration, improves the carrier collection within the bulk, reduces the defects energy level as well as inverts the electric field polarity at grain boundaries(GBs) for Ag-substituted CZTSSe system. Benefiting from this lithium-assisted complex engineering of electrical performance both in grain interior(GI) and GBs, the power conversion efficiency(PCE) is finally increased from 9.21% to 10.29%. This systematic study represents an effective way to overcome the challenges encountered in Ag substitution,and these findings support a new aspect that the synergistic effects of double cation dopant will further pave the way for the development of high efficiency kesterite PV technology.
基金National Natural Science Foundation of China (Nos. 92163118 and 51972234).
文摘In this work,Ag/Ag_(2)Se composite films with excellent thermoelectric(TE)properties and flexibility are prepared based on a simple one-pot method.By adjusting the nominal ratios of Ag/Se,an optimal Ag/Ag_(2)Se composite film shows a large power factor of~2275 μW m^(-1) K^(-2) at 300 K.Such an outstand-ing TE performance of the composite film is due to the unique microstructure and the synergistic effect between the Ag and Ag_(2)Se.Meanwhile,the composite film also shows outstanding flexibility(~91.8%of the initial electrical conductivity is maintained,and the S is unchanged after 1500 bending cycles with a bending radius of 4 mm).Furthermore,a 4-leg flexible TE generator assembled with the optimal film produces a voltage of 14.06 mV and 4.96 μW at a temperature difference of 30.4 K.This work provides a new inspiration for the preparation of flexible Ag_(2)Se-based films with excellent TE performance near room temperature.
文摘High-quality II-VI semiconductor ZnSe nanowires were facilely prepared in the oleic acid and oleylamine mixed solution at low temperatures of 130°C-200°C through an Ag2Se-catalyzed growth mechanism. Oleylamine served as an effective reducing agent and a surfactant in the synthesis. Many of the resultant nanowires were terminated by an Ag2Se catalyst particle at one of their ends, confirming that the nanowire growth followed a catalytic mechanism. The crystal structure of Ag2Se catalyst was examined, which exhibited a metastable tetragonal phase, not the common orthorhombic phase. Meanwhile, the optical properties of as-synthesized ZnSe nanowire solid powder were evaluated by the UV-Visible diffuse reflectance and photoluminescence spectroscopy and a significant blue shift was observed compared to the bulk ZnSe with a band gap of 2.7 eV. This work would provide an alternative and effective catalytic route for the preparation of one-dimensional (1D) nanostructures of ZnSe and other metal selenides.
基金supported by the National Natural Science Foundation of China(61874159,62074052,61974173,52072327,51702085 and 51802081)the Joint Talent Cultivation Funds of NSFC-HN(U1704151 and U1904192)+1 种基金the Zhongyuan Thousand Talents(Zhongyuan Scholars)Program of Henan Province(202101510004)the Science and Technology Innovation Talents in Universities of Henan Province(21HASTIT023)。
文摘The environmentally friendly Cu_(2)ZnSn(S,Se)_(4)(CZTSSe) compounds are promising direct bandgap materials for application in thin film solar cells, but the spontaneous surface defects disordering would lead to large open-circuit voltage deficit(V_(oc,deficit)) and significantly limit kesterite photovoltaics performance,primarily arising from the generated more recombination centers and insufficient p to n conversion at p-n junction. Herein, we establish a surface defects ordering structure in CZTSSe system via local substitution of Cu by Ag to suppress disordered Cu_(Zn) defects and generate benign n-type Zn_(Ag) donors. Taking advantage of the decreased annealing temperature of Ag F post deposition treatment(PDT), the high concentration of Ag incorporated into surface absorber facilitates the formation of surface ordered defect environment similar to that of efficient CIGS PV. The manipulation of highly doped surface structure could effectively reduce recombination centers, increase depletion region width and enlarge the band bending near p-n junction. As a result, the Ag F-PDT device finally achieves maximum efficiency of 12.34% with enhanced V_(oc) of 0.496 V. These results offer a new solution route in surface defects and energy-level engineering, and open the way to build up high quality p-n junction for future development of kesterite technology.
基金financially supported by the Natural Science Foundation of Hebei Province of China(Nos.E2021202011 and E2018202123)Jian-Hua Research Foundation of Hebei University of Technology(No.HB1921)+4 种基金High-strength,Highprecision,Superconducting Rail Transit Aluminum Research and Development and Industrialization Projects(No.2019TSLH0110)"One Belt,One Road"Technology Innovation Cooperation Project of Tianjin(No.18PTZWHZ00220)Ministry of Science and Higher Education of the Russian Federation as part of World-class Research Center program(No.075-15-2020-934)Foundation of Strengthening Program(No.2019-JCJQ-142-00)the Exchange Project of the Third Meeting of the Science and Technology Cooperation Subcommittee of the China-Ukraine Intergovernmental Cooperation Committee(No.CU03-11).
文摘As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities and long lifespan.However,the lack of high-rate anodes that can match the high-power-density cathode hinders the commercial application of SICs.In this work,heterostructured Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite is pre-pared by chemical vapor deposition(CVD)method and investigated as the anode for SICs.Through heterointerface manipulation,Fe/FeSe_(2)/Fe_(3)Se_(4)demonstrates better sodium ion storage performances than the pure FeSe_(2)and FeSe_(2)/Fe_(3)Se_(4).It can deliver a specific capacity of 484.8 mAh·g^(-1)after 100 cycles at 0.5 A·g^(-1),as well as a good capacity retention.The excellent performance of Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components,where FeSe_(2)and Fe_(3)Se_(4) are responsible for offering a high capacity and metallic Fe can server as mini-current collectors,effec-tively accelerating the electron and charge transfer behavior.Meanwhile,the heterointerface significantly facilitates the sodium ion fast transport,and retards the structural variation during cycling.FeSe-1000//activated carbon(AC)SIC affords a high energy density of 112 Wh·kg^(-1)at 107.5 W·kg^(-1),its power density can achieve 10,750 W·kg^(-1)with remained energy density of 44.2 Wh·kg^(-1),as well as an outstanding cycling stability,demonstrating this effective heterointerface engineered anode strategy for high-performance SICs.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 20875001, 20775001, 50532030 & 20771001)Innovation Foundation of Anhui Province (Grant No. 2006KJ007TD)
文摘Coupling TiO2 with a narrow band gap semiconductor acting as the photosensitizer has attracted much attention in solar energy exploitation. In this work,the porous TiO2 film was first formed on the conducting glass plate (CGP) substrate by the decomposition of polyethylene glycol (PEG) mixing in titanium hydroxide sol at 450℃. Then,the TiO2/Ag2Se interface composite film was fabricated by interface reaction of AgNO3 with NaSeSO3 on the activated surface of porous TiO2 film. The results of SEM and XRD analyses indicated that the porous TiO2 layer was made up of the anatase crystal,and the Ag2Se layer was made up of congregative small particles that have low-temperature α-phase structure. Due to its efficient charge separation for the photo-induced electron-hole pairs,the TiO2/Ag2Se interface composite film as-prepared has good photovoltaic property and high photocurrent response for visible light,which have been confirmed by the photoelectrochemical measurements.
基金supported by the National Natural Science Foundation of China(12025505 and 21873050)China Ministry of Science and Technology(2017YFA0208300)+1 种基金the Open Fund Project of State Key Laboratory of Environmentally Friendly Energy Materials(20KFHG08)the Youth Innovation Promotion Association CAS(CX2310007007 and CX2310000091)。
文摘Engineering the electronic properties of catalysts to target intermediate adsorption energy as well as harvest high selectivity represents a promising strategy to design advanced electrocatalysts for efficient CO_(2)electroreduction.Herein,a synergistical tuning on the electronic structure of the Cd Se nanorods is proposed for boosting electrochemical reduction of CO_(2).The synergy of Ag doping coupled with Se vacancies tuned the electronic structure of the CdSe nanorods,which shows the metalloid characterization and thereby the accelerated electron transfer of CO_(2)electroreduction.Operando synchrotron radiation Fourier transform infrared spectroscopy and theoretical simulation revealed that the Ag doping and Se vacancies accelerated the CO_(2)activation process and lowered the energy barrier for the conversion from CO_(2)to;COOH;as a result,the performance of CO_(2)electroreduction was enhanced.The as-obtained metalloid Ag-doped CdSe nanorods exhibited a 2.7-fold increment in current density and 1.9-fold Faradaic efficiency of CO compared with the pristine CdSe nanorod.
