As a hole transport layer, PEDOT:PSS usually limits the stability and efficiency of perovskite solar cells(PSCs) due to its hygroscopic nature and inability to block electrons. Here, a graphene-oxide(GO)-modified PEDO...As a hole transport layer, PEDOT:PSS usually limits the stability and efficiency of perovskite solar cells(PSCs) due to its hygroscopic nature and inability to block electrons. Here, a graphene-oxide(GO)-modified PEDOT:PSS hole transport layer was fabricated by spin-coating a GO solution onto the PEDOT:PSS surface. PSCs fabricated on a GO-modified PEDOT:PSS layer exhibited a power conversion efficiency(PCE) of 15.34%, which is higher than 11.90% of PSCs with the PEDOT:PSS layer.Furthermore, the stability of the PSCs was significantly improved, with the PCE remaining at 83.5% of the initial PCE values after aging for 39 days in air. The hygroscopic PSS material at the PEDOT:PSS surface was partlyremoved during spin-coating with the GO solution, which improves the moisture resistance and decreases the contact barrier between the hole transport layer and perovskite layer. The scattered distribution of the GO at the PEDOT:PSS surface exhibits superior wettability, which helps to form a high-quality perovskite layer with better crystallinity and fewer pin holes. Furthermore, the hole extraction selectivity of the GO further inhibits the carrier recombination at the interface between the perovskite and PEDOT:PSS layers. Therefore, the cooperative interactions of these factors greatly improve the light absorption of the perovskite layer, the carrier transport and collection abilities of the PSCs, and especially the stability of the cells.展开更多
Dip-coated double-wall carbon nanotubes(DWCNTs) and titanium dioxide(TiO2) sol have been prepared and smeared onto the tip of a conductive iron needle which serves as the corona discharge anode in a needle-cylinder co...Dip-coated double-wall carbon nanotubes(DWCNTs) and titanium dioxide(TiO2) sol have been prepared and smeared onto the tip of a conductive iron needle which serves as the corona discharge anode in a needle-cylinder corona system.Compared with the discharge electrode of a CNT-coated needle tip, great advancements have been achieved with the TiO_2/CNT-coated electrode, including higher discharge current, ionic wind velocity, and energy conversion efficiency,together with lower corona onset voltage and power consumption.Several parameters related to the discharge have been phenomenologically and mathematically studied for comparison.Thanks to the morphology reorientation of the CNT layer and the anti-oxidation of TiO_2, better performance of corona discharge induced wind generation of the TiO2/CNT-coated electrode system has been achieved.This novel decoration may provide better thoughts about the corona discharge application and wind generation.展开更多
Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have bee...Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have been formed by a multi-step deposition and natural oxidization of Mg layer. Mg layer thickness,oxygen flow rate and oxidization time were adjusted and the tunnel magnetoresistance(TMR) ratio of optimal MTJs is over 60% at annealing temperature 385. The(001) MgO crystal structure was obtained when the separation distance between MgO target and substrate is less than 6 cm. The TMR ratio of most MgO based MTJs are over 100% at the separation distance of 5 cm and annealing temperature 340. The TMR ratios of MTJs are almost zero when the separation distance ranges from 6 to 10 cm, due to the amorphous nature of the MgO film.展开更多
ZnO thin film was fabricated on tin-doped indium oxide electrode as an electron selective layer of inverted polymer solar cells using magnetron sputtering deposition. Ionic liquid-functionalized carbon nanoparticles(I...ZnO thin film was fabricated on tin-doped indium oxide electrode as an electron selective layer of inverted polymer solar cells using magnetron sputtering deposition. Ionic liquid-functionalized carbon nanoparticles(ILCNs) film was further deposited onto ZnO surfaces by drop-casting ILCNs solution to improve interface properties. The power conversion efficiency(PCE) of inverted polymer solar cells(PSCs)with only ZnO layer was quickly decreased from 2.7% to 2.2% when the thickness of ZnO layer was increased from 15 nm to 60 nm. However, the average PCE of inverted PSCs with ZnO layer modified with ILCNs only decreased from 3.5% to 3.4%, which is comparable to that of traditional PSCs with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) anode buffer layer. The results suggested that the contact barrier between ZnO layer and poly(3-hexylthiophene) and phenyl-C61-butyric acid methylester(P3HT:PCBM)blended film compared to ZnO bulk resistance can more significantly influence the performance of inverted PSCs with sputtered ZnO layer. The vanishment of negative capacitive behavior of inverted PSCs with ILCNs modified ZnO layer indicated ILCNs can greatly decrease the contact barrier of ZnO/P3HT:PCBM interface.展开更多
The poor stability of halide perovskite nanocrystals(NCs)has severely hindered future practical application.Herein,we proposed a facile and effective ligand modification route to synthesize stable CsPbBr_(3) nanocryst...The poor stability of halide perovskite nanocrystals(NCs)has severely hindered future practical application.Herein,we proposed a facile and effective ligand modification route to synthesize stable CsPbBr_(3) nanocrystals by introducing a double-terminal ligand,namely 4,4'-Azobis(4-cyanovalericacid)(CA),to replace the conventional oleic acid(OA)ligand at room temperature.The as-synthesized CsPbBr_(3)-CA not only possesses high photoluminescence quantum yield(72%)related to the reduced trap defects,but also shows significantly improved stability exposure to water,ethanol,light,and/or heat benefiting from the CA ligand anchored to NC surfaces tightly.The photoluminescence intensity of CsPbBr_(3)-CA maintains about 80%and 75%of its initial emission intensity after immersed in water or ethanol for 360 min,respectively,whereas that of the CsPbBr_(3)-OA was quenched completely within a few minutes.Moreover,an all-inorganic white light-emitting diode(LED)covered 126%National Television System Committee(NTSC)standard and 92%Rec.2020 standard was fabricated by combining the green CsPbBr_(3)-CA and commercial red-emitting K2SiF6:Mn4+(KSF)phosphors onto a blue LED chip.Thus,the presented work initiates the development of the room temperature preparation of high quality CsPbBr_(3) and shows prospect for next-generation displays.展开更多
A flexible counter electrode(CE) for dye-sensitized solar cells(DSCs) has been fabricated using a micro-porous polyvinylidene fluoride membrane as support media and sputtered Pt as the catalytic material.Non-conventio...A flexible counter electrode(CE) for dye-sensitized solar cells(DSCs) has been fabricated using a micro-porous polyvinylidene fluoride membrane as support media and sputtered Pt as the catalytic material.Non-conventional structure DSCs have been developed by the fabricated CEs. The Pt metal was sputtered onto one surface of the membrane as the catalytic material. DSCs were assembled by attaching the Ti O2 electrode to the membrane surface without Pt coating. The membrane was with cylindrical pore geometry. It served not only as a substrate for the CE but also as a spacer for the DSC. The fabricated DSC with the flexible membrane CE showed higher photocurrent density than the conventional sandwich devices based on chemically deposited Pt/FTO glass, achieving a photovoltaic conversion efficiency of 4.43%. The results provides useful information in investigation and development of stable, low-cost, simple-design, flexible and lightweight DSCs.展开更多
On the basis of hydrothermal synthesis of Ag-CeO2 microspheres,Ag-CeO2/g-C3N4 composite photocatalyst with heterostructure was prepared by simple solvent evaporation of Ag-CeO2 and g-C3N4.To characterize the compositi...On the basis of hydrothermal synthesis of Ag-CeO2 microspheres,Ag-CeO2/g-C3N4 composite photocatalyst with heterostructure was prepared by simple solvent evaporation of Ag-CeO2 and g-C3N4.To characterize the composition,structure,morphology and light absorption properties of the as-prepared Ag-CeO2/g-C3N4 composites,XRD,FTIR XPS,SEM,TEM,PL,BET and UV-vis DRS were used,respectively.The as-prepared photocatalyst was subjected to photocatalytic degradation of pollutants,and the prepared composite material has excellent photocatalytic activity for photodegradation of methylene blue(MB).The research shows that the photocatalytic properties of Ag-CeO2/g-C3N4 composites were related to the mass ratio of Ag-CeO2 microspheres and g-C3N4 nanosheets.When the ratio of Ag-CeO2 microspheres:g-C3N4 is 1:5,the composites have the highest photocatalytic activity,which was 9.6 and 3.3 times that of single Ag-CeO2 and g-C3N4,respectively.The improvement of photocatalytic activity is attributed to the heterostructure between the composite materials and the addition of noble metal silver,and the degradation of methylene blue by the visible light irradiation material is greatly improved.Finally,an attempt was made to analyze the principle of photocatalytic degradation of pollutants in prepared materials.展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.61275038 and 11274119)
文摘As a hole transport layer, PEDOT:PSS usually limits the stability and efficiency of perovskite solar cells(PSCs) due to its hygroscopic nature and inability to block electrons. Here, a graphene-oxide(GO)-modified PEDOT:PSS hole transport layer was fabricated by spin-coating a GO solution onto the PEDOT:PSS surface. PSCs fabricated on a GO-modified PEDOT:PSS layer exhibited a power conversion efficiency(PCE) of 15.34%, which is higher than 11.90% of PSCs with the PEDOT:PSS layer.Furthermore, the stability of the PSCs was significantly improved, with the PCE remaining at 83.5% of the initial PCE values after aging for 39 days in air. The hygroscopic PSS material at the PEDOT:PSS surface was partlyremoved during spin-coating with the GO solution, which improves the moisture resistance and decreases the contact barrier between the hole transport layer and perovskite layer. The scattered distribution of the GO at the PEDOT:PSS surface exhibits superior wettability, which helps to form a high-quality perovskite layer with better crystallinity and fewer pin holes. Furthermore, the hole extraction selectivity of the GO further inhibits the carrier recombination at the interface between the perovskite and PEDOT:PSS layers. Therefore, the cooperative interactions of these factors greatly improve the light absorption of the perovskite layer, the carrier transport and collection abilities of the PSCs, and especially the stability of the cells.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61504042,61504098,and 61771198)the Natural Science Foundation of Shanghai,China(Grant No.17ZR1447000)the Fundamental Research Funds for the Central Universities,China
文摘Dip-coated double-wall carbon nanotubes(DWCNTs) and titanium dioxide(TiO2) sol have been prepared and smeared onto the tip of a conductive iron needle which serves as the corona discharge anode in a needle-cylinder corona system.Compared with the discharge electrode of a CNT-coated needle tip, great advancements have been achieved with the TiO_2/CNT-coated electrode, including higher discharge current, ionic wind velocity, and energy conversion efficiency,together with lower corona onset voltage and power consumption.Several parameters related to the discharge have been phenomenologically and mathematically studied for comparison.Thanks to the morphology reorientation of the CNT layer and the anti-oxidation of TiO_2, better performance of corona discharge induced wind generation of the TiO2/CNT-coated electrode system has been achieved.This novel decoration may provide better thoughts about the corona discharge application and wind generation.
基金Natural Science Foundation of Shanghai Science and Technology Commission (grant No. 11ZR1411300)Pujiang Talent Program of Shanghai Science and Technology Commission (grant No. 11PJ1402700) for the financial support
文摘Magnetic tunnel junctions(MTJs) based on MgO barrier have been fabricated by sputtering single crystal MgO target and metal Mg target, respectively, using magnetic sputtering system Nordiko 2000. MgO barriers have been formed by a multi-step deposition and natural oxidization of Mg layer. Mg layer thickness,oxygen flow rate and oxidization time were adjusted and the tunnel magnetoresistance(TMR) ratio of optimal MTJs is over 60% at annealing temperature 385. The(001) MgO crystal structure was obtained when the separation distance between MgO target and substrate is less than 6 cm. The TMR ratio of most MgO based MTJs are over 100% at the separation distance of 5 cm and annealing temperature 340. The TMR ratios of MTJs are almost zero when the separation distance ranges from 6 to 10 cm, due to the amorphous nature of the MgO film.
基金supported by National Natural Science Foundation of China (grant Nos.61275038,11274119)Natural Science Foundation of Shanghai Science and Technology Commission (grant No.11ZR1411300)+2 种基金Pujiang Talent Program of Shanghai Science and Technology Commission (grant No.11PJ1402700)Doctoral Fund of Ministry of Education of China (grant No.20110076120017)SRF for ROCS,SEM
文摘ZnO thin film was fabricated on tin-doped indium oxide electrode as an electron selective layer of inverted polymer solar cells using magnetron sputtering deposition. Ionic liquid-functionalized carbon nanoparticles(ILCNs) film was further deposited onto ZnO surfaces by drop-casting ILCNs solution to improve interface properties. The power conversion efficiency(PCE) of inverted polymer solar cells(PSCs)with only ZnO layer was quickly decreased from 2.7% to 2.2% when the thickness of ZnO layer was increased from 15 nm to 60 nm. However, the average PCE of inverted PSCs with ZnO layer modified with ILCNs only decreased from 3.5% to 3.4%, which is comparable to that of traditional PSCs with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) anode buffer layer. The results suggested that the contact barrier between ZnO layer and poly(3-hexylthiophene) and phenyl-C61-butyric acid methylester(P3HT:PCBM)blended film compared to ZnO bulk resistance can more significantly influence the performance of inverted PSCs with sputtered ZnO layer. The vanishment of negative capacitive behavior of inverted PSCs with ILCNs modified ZnO layer indicated ILCNs can greatly decrease the contact barrier of ZnO/P3HT:PCBM interface.
基金supported by the National Natural Science Foundation of China(Nos.61775060,61275100,61761136006,61790583,and 61874043).
文摘The poor stability of halide perovskite nanocrystals(NCs)has severely hindered future practical application.Herein,we proposed a facile and effective ligand modification route to synthesize stable CsPbBr_(3) nanocrystals by introducing a double-terminal ligand,namely 4,4'-Azobis(4-cyanovalericacid)(CA),to replace the conventional oleic acid(OA)ligand at room temperature.The as-synthesized CsPbBr_(3)-CA not only possesses high photoluminescence quantum yield(72%)related to the reduced trap defects,but also shows significantly improved stability exposure to water,ethanol,light,and/or heat benefiting from the CA ligand anchored to NC surfaces tightly.The photoluminescence intensity of CsPbBr_(3)-CA maintains about 80%and 75%of its initial emission intensity after immersed in water or ethanol for 360 min,respectively,whereas that of the CsPbBr_(3)-OA was quenched completely within a few minutes.Moreover,an all-inorganic white light-emitting diode(LED)covered 126%National Television System Committee(NTSC)standard and 92%Rec.2020 standard was fabricated by combining the green CsPbBr_(3)-CA and commercial red-emitting K2SiF6:Mn4+(KSF)phosphors onto a blue LED chip.Thus,the presented work initiates the development of the room temperature preparation of high quality CsPbBr_(3) and shows prospect for next-generation displays.
基金supported by National Natural Science Foundation of China(No.10774046)Shanghai Municipal Science&Technology Committee(No.09JC1404600+1 种基金No.0852nm06100 and No.08230705400)Singapore Ministry of Education innovation fund(MOE IF Funding MOE2008-IF-1-016)
文摘A flexible counter electrode(CE) for dye-sensitized solar cells(DSCs) has been fabricated using a micro-porous polyvinylidene fluoride membrane as support media and sputtered Pt as the catalytic material.Non-conventional structure DSCs have been developed by the fabricated CEs. The Pt metal was sputtered onto one surface of the membrane as the catalytic material. DSCs were assembled by attaching the Ti O2 electrode to the membrane surface without Pt coating. The membrane was with cylindrical pore geometry. It served not only as a substrate for the CE but also as a spacer for the DSC. The fabricated DSC with the flexible membrane CE showed higher photocurrent density than the conventional sandwich devices based on chemically deposited Pt/FTO glass, achieving a photovoltaic conversion efficiency of 4.43%. The results provides useful information in investigation and development of stable, low-cost, simple-design, flexible and lightweight DSCs.
基金Project supported by the National Natural Science Foundation of China(51478285,21407111)Natural Science Foundation of Jiangsu Province(BK20180971,BK20180103)
文摘On the basis of hydrothermal synthesis of Ag-CeO2 microspheres,Ag-CeO2/g-C3N4 composite photocatalyst with heterostructure was prepared by simple solvent evaporation of Ag-CeO2 and g-C3N4.To characterize the composition,structure,morphology and light absorption properties of the as-prepared Ag-CeO2/g-C3N4 composites,XRD,FTIR XPS,SEM,TEM,PL,BET and UV-vis DRS were used,respectively.The as-prepared photocatalyst was subjected to photocatalytic degradation of pollutants,and the prepared composite material has excellent photocatalytic activity for photodegradation of methylene blue(MB).The research shows that the photocatalytic properties of Ag-CeO2/g-C3N4 composites were related to the mass ratio of Ag-CeO2 microspheres and g-C3N4 nanosheets.When the ratio of Ag-CeO2 microspheres:g-C3N4 is 1:5,the composites have the highest photocatalytic activity,which was 9.6 and 3.3 times that of single Ag-CeO2 and g-C3N4,respectively.The improvement of photocatalytic activity is attributed to the heterostructure between the composite materials and the addition of noble metal silver,and the degradation of methylene blue by the visible light irradiation material is greatly improved.Finally,an attempt was made to analyze the principle of photocatalytic degradation of pollutants in prepared materials.