Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the d...Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.展开更多
Cd_(1-x)Zn_(x)S thin films were deposited by chemical bath deposition(CBD)on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film.The SEM resul...Cd_(1-x)Zn_(x)S thin films were deposited by chemical bath deposition(CBD)on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film.The SEM results show that the thin film surfaces under the cadmium sulfate concentration of 0.005 M exhibit better compactness and uniformity.The distribution diagrams of thin film elements illustrate the film growth rate changes on the trend of the increase,decrease,and increase with the increase of cadmium sulfate concentration.XRD studies exhibit the crystal structure of the film is the hexagonal phase,and there are obvious diffraction peaks and better crystallinity when the concentration is 0.005 M.Spectrophotometer test results demonstrate that the relationship between zinc content x and optical band gap value E_(g) can be expressed by the equation E_(g)(x)=0.59x^(2)+0.69x+2.43.Increasing the zinc content can increase the optical band gap,and the absorbance of the thin film can be improved by decreasing the cadmium sulfate concentration,however,all of them have good transmittance.At a concentration of 0.005 M,the thin film has good absorbance in the 300-800 nm range,80%transmittance,and band gap value of 3.24 eV,which is suitable for use as a buffer layer for solar cells.展开更多
Polycrystalline ZnS films were prepared by pulsed laser deposition （PLD） on quartz glass substrates under different growth conditions at different substrate temperatures of 20, 200, 400, and 600 ℃, which is a suita...Polycrystalline ZnS films were prepared by pulsed laser deposition （PLD） on quartz glass substrates under different growth conditions at different substrate temperatures of 20, 200, 400, and 600 ℃, which is a suitable alternative to chemical bath deposited （CBD） CdS as a buffer layer in Cu（In,Ga）Se2 （CIGS） solar cells. X-ray diffraction studies indicate the films are polycrystalline with zinc-blende structure and they exhibit preferential orientation along the cubic phase β-ZnS （111） direction, which conflicts with the conclusion of wurtzite structure by Murali that the ZnS films deposited by pulse plating technique was polycrystalline with wurtzite structure. The Raman spectra of grown films show Al mode at approximately 350 cm^-1, generally observed in the cubic phase β-ZnS compounds. The planar and the cross-sectional morphology were observed by scanning electron microscopic. The dense, smooth, uniform grains are formed on the quartz glass substrates through PLD technique. The grain size of ZnS deposited by PLD is much smaller than that of CdS by conventional CBD method, which is analyzed as the main reason of detrimental cell performance. The composition of the ZnS films was also measured by X-ray fluorescence. The typical ZnS films obtained in this work are near stoichiometric and only a small amount of S-rich. The energy band gaps at different temperatures were obtained by absorption spectroscopy measurement, which increases from 3.2 eV to 3.7 eV with the increasing of the deposition temperature. ZnS has a wider energy band gap than CdS （2.4 eV）, which can enhance the blue response of the photovoltaic cells. These results show the high-quality of these substitute buffer layer materials are prepared through an all-dry technology, which can be used in the manufacture of CIGS thin film solar cells.展开更多
High power conversion efficiency(PCE)flexible perovskite solar cells(FPSCs)are highly desired power sources for aerospace crafts and flexible electronics.However,their PCEs still lag far behind their rigid counterpart...High power conversion efficiency(PCE)flexible perovskite solar cells(FPSCs)are highly desired power sources for aerospace crafts and flexible electronics.However,their PCEs still lag far behind their rigid counterparts.Herein,we report a high PCE FPSC by controllable growth of a SnO_(2)electron transport layer through constant pH chemical bath deposition(CBD).The application of SnSO_(4)as tin source enables us to perform CBD without strong acid,which in turn makes it applicable to acid-sensitive flexible indium tin oxide.Furthermore,a mild and controllable growth environment leads to uniform particle growth and dense SnO_(2)deposition with full coverage and reproducibility,resulting in a record PCE of up to 25.09%(certified 24.90%)for FPSCs to date.The as-fabricated FPSCs exhibited high durability,maintaining over 90% of their initial PCE after 10000 bending cycles.展开更多
This research paper reports the fabrication and evaluation of titanium dioxide(TiO_(2))-and zinc oxide(ZnO)-based dye-sensitized solar cells with anthocyanin dye extracted from pomegranate.TiO_(2) and ZnO were synthes...This research paper reports the fabrication and evaluation of titanium dioxide(TiO_(2))-and zinc oxide(ZnO)-based dye-sensitized solar cells with anthocyanin dye extracted from pomegranate.TiO_(2) and ZnO were synthesized using the hydrothermal synthesis and chemical bath deposition techniques,respectively.The scanning electron microscopy analysis showed that TiO_(2) had nanopillars made up of nano rods with dimensions of 111.866,90.521,and 81.908 nm,while ZnO had hexagonal patterned nanorods with lengths of 283.294 nm and diameters of 91.782 nm.The absorption spectra of the pomegranate dye were analysed and the strongest absorp-tion peak was found to be at 520 nm,which corresponds to the existing anthocyanin pigment.The band gap of pomegranate dye was noted down to be 2.45 eV.The performance of the dye-sensitized solar cells was evaluated using one sun illumination(100 mW/cm^(2))where the dye-sensitized solar cell with TiO_(2) nanopillars achieved an improved efficiency of 0.46%whereas the dye-sensitized solar cell with ZnO nanorods showed a considerably reduced efficiency of 0.42%.展开更多
As a convenient,low-cost and up-scalable solution route,chemical bath deposition(CBD)has exhibited impressive advantages in fabricating electron transporting materials like SnO_(2),achieving record efficien-cies for r...As a convenient,low-cost and up-scalable solution route,chemical bath deposition(CBD)has exhibited impressive advantages in fabricating electron transporting materials like SnO_(2),achieving record efficien-cies for regular n-i-p perovskite solar cells(PSCs).However,for the hysteresis-free and potentially more stable inverted p-i-n PSCs,CBD processing is rarely studied to improve the device performance.In this work,we first present a CBD planar NiO x film as the efficient hole transport layer for the inverted per-ovskite solar cells(IPSCs).The morphologies and semiconducting properties of the NiO x film can be ad-justed by varying the concentration of[Ni(H 2 O)x(NH 3)6-x]2+cation via in-situ monitoring of the CBD re-action process.The characterizations of ultraviolet photoelectron spectroscopy,transient absorption spec-troscopy,time-resolved photoluminescence suggest that the CBD planar NiO x film possesses enhanced conductivity and aligned energy band levels with perovskite,which benefits for the charge transport in the IPSCs.The devices based on planar NiO x at 50°C and low nickel precursor concentration achieved an enhanced efficiency from 16.14%to 18.17%.This work established an efficient CBD route to fabricate planar NiO x film for PSCs and paved the way for high performance PSCs with CBD-prepared hole transporting materials.展开更多
Insertion of a C-containing layer in a metal/Ge structure,using a chemical bath,enabled the Schottky barrier height（SBH） to be modulated.Chemical baths with 1-octadecene,1-hexadecene,1-tetradecene,and 1- dodecene we...Insertion of a C-containing layer in a metal/Ge structure,using a chemical bath,enabled the Schottky barrier height（SBH） to be modulated.Chemical baths with 1-octadecene,1-hexadecene,1-tetradecene,and 1- dodecene were used separately with Ge substrates.An ultrathin C-containing layer stops the penetration of free electron wave functions from the metal to the Ge.Metal-induced gap states are alleviated and the pinned Fermi level is released.The SBH is lowered to 0.17 eV.This new formation method is much less complex than traditional ones,and the result is very good.展开更多
Titanium oxide thin films were prepared on self-assembled monolayers-coated silicon substrate using layer-by-layer self-assembly method and chemical bath deposition from an aqueous solution. The effects of temperature...Titanium oxide thin films were prepared on self-assembled monolayers-coated silicon substrate using layer-by-layer self-assembly method and chemical bath deposition from an aqueous solution. The effects of temperature on structural properties, thickness and morphologies of titanium oxide thin films were investigated. The results show that the absorption peak of peroxo complexes of titanium at 410 nm decreases gradually with increasing the temperature. The deposited films consisting of titanium oxide nanocrystals are believed to be fully amorphous by XRD. Titanium oxide thin films fabricated at 60 °C for 2 h are continuous, dense and homogeneous with a size in the range of 20-40 nm by SEM. The chemical compositions of deposited thin films were studied by EDS, and the mole ratio of O to Ti is 2.2：1.展开更多
The Zn(O,S)thin film is considered a most promising candidate for a cadmium-free buffer layer of the Cu(In,Ga)Se_(2)(CIGS)thin-film solar cell due to its advantages of optical responses in the short-wavelength region ...The Zn(O,S)thin film is considered a most promising candidate for a cadmium-free buffer layer of the Cu(In,Ga)Se_(2)(CIGS)thin-film solar cell due to its advantages of optical responses in the short-wavelength region and adjustable bandgap.In this paper,the thin-film growth mechanism and process optimization of Zn(O,S)films fabricated using the chemical bath deposition method are sys-tematically investigated.The thickness and quality of Zn(O,S)films were found to be strongly affected by the concentration variation of the precursor chemicals.It was also revealed that different surface morphologies of Zn(O,S)films would appear if the reaction time were changed and,subsequently,the optimum reaction time was defined.The film-growth curve suggested that the growth rate varied linearly with the deposition temperature and some defects appeared when the temperature was too high.In addition,to further improve the film quality,an effective post-treatment approach was proposed and the experimental results showed that the microstructure of the Zn(O,S)thin film was improved by an ammonia etching process followed by an annealing process.For com-parison purposes,both Zn(O,S)-based and CdS-based devices were fabricated and characterized.The device with a Zn(O,S)-CIGS solar cell after post-treatment showed near conversion efficiency comparable to that of the device with the CdS-CIGS cell.展开更多
Self-cleaning surfaces have received a great deal of attention recently,both in theoretical studies and commercial applications.The self-cleaning surface of lotus leaf is hydrophobic and rough,showing a micro-and nano...Self-cleaning surfaces have received a great deal of attention recently,both in theoretical studies and commercial applications.The self-cleaning surface of lotus leaf is hydrophobic and rough,showing a micro-and nano-scale morphology.The micro-reliefs of lotus leaf were mimicked using polyvinylidene fluoride(PVDF)film and nano-scale peaks on the top of the micro-reliefs were implemented by the reaction between methyltrichlorosilane and the reactive groups of PVDF film treated by oxygen plasma.A lotus-leaf-like surface of the PVDF film was clearly observed by scanning electronic microscopy(SEM)and atomic force microscope(AFM).Elemental composition analysis by X-ray photoelectron spectroscopy(XPS)revealed that the material of the nanostructure of PVDF film was polymethylsiloxane.The superhydrophobic property of the mimicked self-cleaning surface was validated by the water contact angle and sliding angle on the lotus-leaf-like PVDF film,which were 156.6° and 4°,respectively.In this case,water droplets can easily move across the PVDF film surface,carrying dirt particles away,leaving no contamination.展开更多
文摘Recent efforts have focused on the fabrication and application of three- dimensional （3-D） nanoarchitecture electrodes, which can exhibit excellent electrochemical performance. Herein, a novel strategy towards the design and synthesis of size- and thickness-tunable two-dimensional （2-D） MnO2 nanosheets on highly conductive one-dimensional （l-D） backbone arrays has been developed via a facile, one-step enhanced chemical bath deposition （ECBD） method at a low temperature （-50 ℃）. Inclusion of an oxidizing agent, BrO3-, in the solution was crucial in controlling the heterogeneous nucleation and growth of the nanosheets, and in inducing the formation of the tailored and uniformly arranged nanosheet arrays. We fabricated supercapacitor devices based on 3-D MnO2 nanosheets with conductive Sb-doped SnO2 nanobelts as the backbone. They achieved a specific capacitance of 162 F·g-1 at an extremely high current density of 20 A·g% and good cycling stability that shows a capacitance retention of -92% of its initial value, along with a coulombic efficiency of almost 100% after 5,000 cycles in an aqueous solution of I M Na2SO4. The results were attributed to the unique hierarchical structures, which provided a short diffusion path of electrolyte ions by means of the 2-D sheets and direct electrical connections to the current collector by 1-D arrays as well as the prevention of aggregation by virtue of the well-aligned 3-D structure.
基金This work was supported by the Tianjin Municipal Education Commission,Horizontal subject(grant number 70304901).
文摘Cd_(1-x)Zn_(x)S thin films were deposited by chemical bath deposition(CBD)on the glass substrate to study the influence of cadmium sulfate concentration on the structural characteristics of the thin film.The SEM results show that the thin film surfaces under the cadmium sulfate concentration of 0.005 M exhibit better compactness and uniformity.The distribution diagrams of thin film elements illustrate the film growth rate changes on the trend of the increase,decrease,and increase with the increase of cadmium sulfate concentration.XRD studies exhibit the crystal structure of the film is the hexagonal phase,and there are obvious diffraction peaks and better crystallinity when the concentration is 0.005 M.Spectrophotometer test results demonstrate that the relationship between zinc content x and optical band gap value E_(g) can be expressed by the equation E_(g)(x)=0.59x^(2)+0.69x+2.43.Increasing the zinc content can increase the optical band gap,and the absorbance of the thin film can be improved by decreasing the cadmium sulfate concentration,however,all of them have good transmittance.At a concentration of 0.005 M,the thin film has good absorbance in the 300-800 nm range,80%transmittance,and band gap value of 3.24 eV,which is suitable for use as a buffer layer for solar cells.
基金ACKNOWLEDGMENTS This work was supported by the National Basic Research Program of China （No.2006CB92200） and the National Natural Science Foundation of China （No.10774136）.
文摘Polycrystalline ZnS films were prepared by pulsed laser deposition （PLD） on quartz glass substrates under different growth conditions at different substrate temperatures of 20, 200, 400, and 600 ℃, which is a suitable alternative to chemical bath deposited （CBD） CdS as a buffer layer in Cu（In,Ga）Se2 （CIGS） solar cells. X-ray diffraction studies indicate the films are polycrystalline with zinc-blende structure and they exhibit preferential orientation along the cubic phase β-ZnS （111） direction, which conflicts with the conclusion of wurtzite structure by Murali that the ZnS films deposited by pulse plating technique was polycrystalline with wurtzite structure. The Raman spectra of grown films show Al mode at approximately 350 cm^-1, generally observed in the cubic phase β-ZnS compounds. The planar and the cross-sectional morphology were observed by scanning electron microscopic. The dense, smooth, uniform grains are formed on the quartz glass substrates through PLD technique. The grain size of ZnS deposited by PLD is much smaller than that of CdS by conventional CBD method, which is analyzed as the main reason of detrimental cell performance. The composition of the ZnS films was also measured by X-ray fluorescence. The typical ZnS films obtained in this work are near stoichiometric and only a small amount of S-rich. The energy band gaps at different temperatures were obtained by absorption spectroscopy measurement, which increases from 3.2 eV to 3.7 eV with the increasing of the deposition temperature. ZnS has a wider energy band gap than CdS （2.4 eV）, which can enhance the blue response of the photovoltaic cells. These results show the high-quality of these substitute buffer layer materials are prepared through an all-dry technology, which can be used in the manufacture of CIGS thin film solar cells.
基金financially supported by the National Key Research and Development Program of China(2022YFB3803304)National Natural Science Foundation of China(U23B20153,U23A20138)+5 种基金Tsinghua University Initiative Scientific Research Program(20221080065,20223080044)Independent Innovative Research Program(ZK20230101)Department of Electrical Engineering,Tsinghua University,State Key Laboratory of Power System and Generation Equipment(Nos.SKLD21Z03 and SKLD20M03)China Postdoctoral Science Foundation(2023M741888)The Chinese Thousand Talents Program for Young ProfessionalsState Grid Corporation of China,National Bio Energy Co.Ltd.,grant no.52789922000D.
文摘High power conversion efficiency(PCE)flexible perovskite solar cells(FPSCs)are highly desired power sources for aerospace crafts and flexible electronics.However,their PCEs still lag far behind their rigid counterparts.Herein,we report a high PCE FPSC by controllable growth of a SnO_(2)electron transport layer through constant pH chemical bath deposition(CBD).The application of SnSO_(4)as tin source enables us to perform CBD without strong acid,which in turn makes it applicable to acid-sensitive flexible indium tin oxide.Furthermore,a mild and controllable growth environment leads to uniform particle growth and dense SnO_(2)deposition with full coverage and reproducibility,resulting in a record PCE of up to 25.09%(certified 24.90%)for FPSCs to date.The as-fabricated FPSCs exhibited high durability,maintaining over 90% of their initial PCE after 10000 bending cycles.
文摘This research paper reports the fabrication and evaluation of titanium dioxide(TiO_(2))-and zinc oxide(ZnO)-based dye-sensitized solar cells with anthocyanin dye extracted from pomegranate.TiO_(2) and ZnO were synthesized using the hydrothermal synthesis and chemical bath deposition techniques,respectively.The scanning electron microscopy analysis showed that TiO_(2) had nanopillars made up of nano rods with dimensions of 111.866,90.521,and 81.908 nm,while ZnO had hexagonal patterned nanorods with lengths of 283.294 nm and diameters of 91.782 nm.The absorption spectra of the pomegranate dye were analysed and the strongest absorp-tion peak was found to be at 520 nm,which corresponds to the existing anthocyanin pigment.The band gap of pomegranate dye was noted down to be 2.45 eV.The performance of the dye-sensitized solar cells was evaluated using one sun illumination(100 mW/cm^(2))where the dye-sensitized solar cell with TiO_(2) nanopillars achieved an improved efficiency of 0.46%whereas the dye-sensitized solar cell with ZnO nanorods showed a considerably reduced efficiency of 0.42%.
基金supported by the National Key Re-search and Development Plan(2017YFE0131900,2019YFE0107200)the National Natural Science Foundation of China(52072284,21875178,91963209)+1 种基金the Science and Technology Department of Hubei Province(2020CFB427)Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory(XHD2020-001).
文摘As a convenient,low-cost and up-scalable solution route,chemical bath deposition(CBD)has exhibited impressive advantages in fabricating electron transporting materials like SnO_(2),achieving record efficien-cies for regular n-i-p perovskite solar cells(PSCs).However,for the hysteresis-free and potentially more stable inverted p-i-n PSCs,CBD processing is rarely studied to improve the device performance.In this work,we first present a CBD planar NiO x film as the efficient hole transport layer for the inverted per-ovskite solar cells(IPSCs).The morphologies and semiconducting properties of the NiO x film can be ad-justed by varying the concentration of[Ni(H 2 O)x(NH 3)6-x]2+cation via in-situ monitoring of the CBD re-action process.The characterizations of ultraviolet photoelectron spectroscopy,transient absorption spec-troscopy,time-resolved photoluminescence suggest that the CBD planar NiO x film possesses enhanced conductivity and aligned energy band levels with perovskite,which benefits for the charge transport in the IPSCs.The devices based on planar NiO x at 50°C and low nickel precursor concentration achieved an enhanced efficiency from 16.14%to 18.17%.This work established an efficient CBD route to fabricate planar NiO x film for PSCs and paved the way for high performance PSCs with CBD-prepared hole transporting materials.
基金supported by the Chinese National Key Basic Research Program(No.2011CBA00602)the National Key Scientific and Technological Projects,China(Nos.2009ZX02035-004-02,2011ZX02708-002)
文摘Insertion of a C-containing layer in a metal/Ge structure,using a chemical bath,enabled the Schottky barrier height（SBH） to be modulated.Chemical baths with 1-octadecene,1-hexadecene,1-tetradecene,and 1- dodecene were used separately with Ge substrates.An ultrathin C-containing layer stops the penetration of free electron wave functions from the metal to the Ge.Metal-induced gap states are alleviated and the pinned Fermi level is released.The SBH is lowered to 0.17 eV.This new formation method is much less complex than traditional ones,and the result is very good.
基金Projects(51204036,51234009)supported by the National Natural Science Foundation of ChinaProject(20110042120014)supported by the Research Fund for the Doctoral Program of Higher Education,China
文摘Titanium oxide thin films were prepared on self-assembled monolayers-coated silicon substrate using layer-by-layer self-assembly method and chemical bath deposition from an aqueous solution. The effects of temperature on structural properties, thickness and morphologies of titanium oxide thin films were investigated. The results show that the absorption peak of peroxo complexes of titanium at 410 nm decreases gradually with increasing the temperature. The deposited films consisting of titanium oxide nanocrystals are believed to be fully amorphous by XRD. Titanium oxide thin films fabricated at 60 °C for 2 h are continuous, dense and homogeneous with a size in the range of 20-40 nm by SEM. The chemical compositions of deposited thin films were studied by EDS, and the mole ratio of O to Ti is 2.2：1.
基金financially supported by National Key R&D Program of China(grant no.2018YFB1500200).
文摘The Zn(O,S)thin film is considered a most promising candidate for a cadmium-free buffer layer of the Cu(In,Ga)Se_(2)(CIGS)thin-film solar cell due to its advantages of optical responses in the short-wavelength region and adjustable bandgap.In this paper,the thin-film growth mechanism and process optimization of Zn(O,S)films fabricated using the chemical bath deposition method are sys-tematically investigated.The thickness and quality of Zn(O,S)films were found to be strongly affected by the concentration variation of the precursor chemicals.It was also revealed that different surface morphologies of Zn(O,S)films would appear if the reaction time were changed and,subsequently,the optimum reaction time was defined.The film-growth curve suggested that the growth rate varied linearly with the deposition temperature and some defects appeared when the temperature was too high.In addition,to further improve the film quality,an effective post-treatment approach was proposed and the experimental results showed that the microstructure of the Zn(O,S)thin film was improved by an ammonia etching process followed by an annealing process.For com-parison purposes,both Zn(O,S)-based and CdS-based devices were fabricated and characterized.The device with a Zn(O,S)-CIGS solar cell after post-treatment showed near conversion efficiency comparable to that of the device with the CdS-CIGS cell.
基金Tianjin Municipal Science and Technology Commission,China(No.06YFJZJC14802)
文摘Self-cleaning surfaces have received a great deal of attention recently,both in theoretical studies and commercial applications.The self-cleaning surface of lotus leaf is hydrophobic and rough,showing a micro-and nano-scale morphology.The micro-reliefs of lotus leaf were mimicked using polyvinylidene fluoride(PVDF)film and nano-scale peaks on the top of the micro-reliefs were implemented by the reaction between methyltrichlorosilane and the reactive groups of PVDF film treated by oxygen plasma.A lotus-leaf-like surface of the PVDF film was clearly observed by scanning electronic microscopy(SEM)and atomic force microscope(AFM).Elemental composition analysis by X-ray photoelectron spectroscopy(XPS)revealed that the material of the nanostructure of PVDF film was polymethylsiloxane.The superhydrophobic property of the mimicked self-cleaning surface was validated by the water contact angle and sliding angle on the lotus-leaf-like PVDF film,which were 156.6° and 4°,respectively.In this case,water droplets can easily move across the PVDF film surface,carrying dirt particles away,leaving no contamination.
