Significant interest has been focused on graphene materials for their unique properties as Hydrogen storage materials. The development of their abilities by modifying their configuration with doped or decorated transi...Significant interest has been focused on graphene materials for their unique properties as Hydrogen storage materials. The development of their abilities by modifying their configuration with doped or decorated transition metals </span><span style="font-family:Verdana;">was also of great interest. In this work</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> using the DFT/B3LYP/6-31G/LanL2DZ</span><span style="font-family:Verdana;"> level of theory, graphene sheet (GS) as one of the materials of interest was doped with two transition metals, Osmium (Os) and Tungsten (W). Two active sites on the GS were tested (C4 and C16) resulted into adsorbed systems, H2@C4-GS and H2@C16-GS. C16 position showed the largest adsorption energy compared to that at C4. Therefore, C4 was replaced by the two metals and two adsorbed systems were formed</span><span style="font-family:Verdana;">: </span><span style="font-family:Verdana;">H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS and H2@W-GS. The binding energy of H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS was found to be greater than that of H2@W-GS.展开更多
In organic solar cells(OSCs),it is an effective way to improve the power conversion efficiency(PCE)by adding a guest component with appropriate absorption and energy levels in the host system.Herein,a new nonfullerene...In organic solar cells(OSCs),it is an effective way to improve the power conversion efficiency(PCE)by adding a guest component with appropriate absorption and energy levels in the host system.Herein,a new nonfullerene acceptor(NFA)named TBF-2Cl was developed by the strategy of expanding theπconjugated core of 2,2’-(((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b’]dithiophene-2,7-diyl)bis(methaneylylidene))bis(5,6-dichloro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(IDT-4Cl)with two benzene rings.With increase of benzene units,TBF-2Cl exhibits higher lowest unoccupied molecular orbital(LUMO)level of-3.75 eV than that of one benzene unit based NFA IDT-4Cl and fluorene core based NFA F-2Cl,which facilitates enhancing the open-circuit voltage(V_(oc))of ternary devices.Moreover,TBF-2Cl film shows a medium optical bandgap with the absorption range from 500-800 nm,being well complementary with the wide bandgap polymer donor D18 and narrow bandgap NFA CH-6F.Accordingly,a remarkable PCE of 18.92%with a high short-circuit current density(J_(sc))of 27.40 mA·cm^(-2),a fill factor(FF)of 0.749,especially an outstanding V_(oc) of 0.922 V was achieved for the optimal ternary device based on D18:TBF-2Cl:CH-6F,surpassing the binary counterpart(17.08%).The findings provide insight into the development of new guest acceptors for obtaining more efficient OSCs.展开更多
Imide-based conjugated molecules have emerged as a highly promising class of building blocks for constructing n-type semiconducting materials with lowlying lowest unoccupied molecular orbitals and exceptional stabilit...Imide-based conjugated molecules have emerged as a highly promising class of building blocks for constructing n-type semiconducting materials with lowlying lowest unoccupied molecular orbitals and exceptional stability.Although imides,such as naphthalene diimides,perylene diimides and their lateral fused analogs,have been synthesized extensively,the design and synthesis of largerπ-extended molecules incorporating more than two imide groups are desirable but still very challenging.Herein,we report the synthesis of an unprecedented electron-deficient bisanthene tetraimide(ATI)containing a bisantheneconjugated core and four five-membered imide groups,which was successfully achieved via a combined approach of solution and on-surface synthesis.The chemical structures,electronic states,formation mechanism and aromaticity of ATI were systematically investigated by scanning tunneling microscopy,noncontact atomic force microscopy,scanning tunneling spectroscopy,and density functional theory calculations.展开更多
Organic cathodes for alkali-metal-ion batteries attract great attentions in recent years,but the ion storage sites are limited to some finite functional groups.This is because an organic cathode must have proper lowes...Organic cathodes for alkali-metal-ion batteries attract great attentions in recent years,but the ion storage sites are limited to some finite functional groups.This is because an organic cathode must have proper lowest unoccupied molecular orbitals(LUMO) to accept electrons at high potential.Herein,a novel type of organophosphate-based cathode has successfully been explored by tuning the LUMO energy level of organophosphates through metal ions with an inert electron pair.For the first time,the P=O of phytate(PA),N,N,N’,N’-ethylenediaminetetrakis(methylene phytate)(EDTMP),and diethylenetriaminepentakis(methyl phytate)(DTPMP) is activated by lead/bismuth(with 6s2electron pair) to storage Li/Na/K ions reversibly.Typically,density functional theory calculations indicate that the LUMO energy of Bi-PA is greatly reduced from-0.99(PA) to-4.61 eV,which shows the first discharge capacity of 173,182 and 206mAh·g-1and the reversibly capacity of 102,102 and 101mAh·g-1with the discharge platform of 2.4,2.1 and 2.4 V for Li/Na/K-ion battery cathodes,respectively.Similarly,with proper LUMO energy level,Pb-PA(-4.63 eV),Pb-EDTMP(-3.71 eV),and Pb-DTPMP(-4.45 eV) all exhibit admirable performance.This unique strategy of organic materials to alkali-metal-ion battery cathodes offers a new avenue for future energy storage systems.展开更多
To increase the current density of the hole only device, 1, 4, 5, 8, 9, 11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) material has been inserted in the device at the indium tin oxide (ITO)/organic interface. Since ...To increase the current density of the hole only device, 1, 4, 5, 8, 9, 11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) material has been inserted in the device at the indium tin oxide (ITO)/organic interface. Since HATCN molecule can withdraw electrons, it can alter electronic properties of the electrodes and hence inserted between the organic/metal interfaces. This paper deals with the optimization of the thickness of organic-metal layers to enhance the efficiency. Also, efforts have been made to increase the current density and reduce the operating voltage of the device. The material 2, 7-bis [N, N-bis (4- methoxy-phenyl) amino]-9, 9-spirobifluorene (Meo-Spiro-TPD) is used to simulate the hole only device because it is a thermally stable hole transport material. Simulated results shows that better current density values can be achieved compared to fabricated one by optimizing the organic metal layer thickness. The best optimized layer thickness of 22 nm for Alq3, 25 nm for *CBP doped with Ir(ppy)3, 9 nm for Meo-Spiro TPD and 4 nm for HAT-CN which results in current density of 0.12 A/cm2 with a reduction in operating voltage by approximately 2 V.展开更多
文摘Significant interest has been focused on graphene materials for their unique properties as Hydrogen storage materials. The development of their abilities by modifying their configuration with doped or decorated transition metals </span><span style="font-family:Verdana;">was also of great interest. In this work</span><span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> using the DFT/B3LYP/6-31G/LanL2DZ</span><span style="font-family:Verdana;"> level of theory, graphene sheet (GS) as one of the materials of interest was doped with two transition metals, Osmium (Os) and Tungsten (W). Two active sites on the GS were tested (C4 and C16) resulted into adsorbed systems, H2@C4-GS and H2@C16-GS. C16 position showed the largest adsorption energy compared to that at C4. Therefore, C4 was replaced by the two metals and two adsorbed systems were formed</span><span style="font-family:Verdana;">: </span><span style="font-family:Verdana;">H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS and H2@W-GS. The binding energy of H</span><sub><span style="font-family:Verdana;vertical-align:sub;">2</span></sub><span style="font-family:Verdana;">@Os-GS was found to be greater than that of H2@W-GS.
基金supported by the National Natural Science Foundation of China(No.52173010)Jining University(Nos.2022HHKJ11,2019BSZX01).
文摘In organic solar cells(OSCs),it is an effective way to improve the power conversion efficiency(PCE)by adding a guest component with appropriate absorption and energy levels in the host system.Herein,a new nonfullerene acceptor(NFA)named TBF-2Cl was developed by the strategy of expanding theπconjugated core of 2,2’-(((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b’]dithiophene-2,7-diyl)bis(methaneylylidene))bis(5,6-dichloro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(IDT-4Cl)with two benzene rings.With increase of benzene units,TBF-2Cl exhibits higher lowest unoccupied molecular orbital(LUMO)level of-3.75 eV than that of one benzene unit based NFA IDT-4Cl and fluorene core based NFA F-2Cl,which facilitates enhancing the open-circuit voltage(V_(oc))of ternary devices.Moreover,TBF-2Cl film shows a medium optical bandgap with the absorption range from 500-800 nm,being well complementary with the wide bandgap polymer donor D18 and narrow bandgap NFA CH-6F.Accordingly,a remarkable PCE of 18.92%with a high short-circuit current density(J_(sc))of 27.40 mA·cm^(-2),a fill factor(FF)of 0.749,especially an outstanding V_(oc) of 0.922 V was achieved for the optimal ternary device based on D18:TBF-2Cl:CH-6F,surpassing the binary counterpart(17.08%).The findings provide insight into the development of new guest acceptors for obtaining more efficient OSCs.
基金support from the National Natural Science Foundation of China(grant nos.22161132026,21790053,51821002,and 21602225)the Suzhou Key Laboratory of Surface and Interface Intelligent Matter(grant no.SZS2022011)+2 种基金the Collaborative Innovation Center of Suzhou Nano Science and Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the 111 project.
文摘Imide-based conjugated molecules have emerged as a highly promising class of building blocks for constructing n-type semiconducting materials with lowlying lowest unoccupied molecular orbitals and exceptional stability.Although imides,such as naphthalene diimides,perylene diimides and their lateral fused analogs,have been synthesized extensively,the design and synthesis of largerπ-extended molecules incorporating more than two imide groups are desirable but still very challenging.Herein,we report the synthesis of an unprecedented electron-deficient bisanthene tetraimide(ATI)containing a bisantheneconjugated core and four five-membered imide groups,which was successfully achieved via a combined approach of solution and on-surface synthesis.The chemical structures,electronic states,formation mechanism and aromaticity of ATI were systematically investigated by scanning tunneling microscopy,noncontact atomic force microscopy,scanning tunneling spectroscopy,and density functional theory calculations.
基金financially supported by the Science and Technology Commission of Shanghai Municipality (No. 22ZR1471300)the National Science Foundation of China (Nos. 21871008,51922103 and 21801247)+1 种基金the Key Research Program of Chinese Academy of Sciences (No.QYZDJ-SSW-JSC013)China Postdoctoral Science Foundation (Nos.2020M671242 and 2021T140688)。
文摘Organic cathodes for alkali-metal-ion batteries attract great attentions in recent years,but the ion storage sites are limited to some finite functional groups.This is because an organic cathode must have proper lowest unoccupied molecular orbitals(LUMO) to accept electrons at high potential.Herein,a novel type of organophosphate-based cathode has successfully been explored by tuning the LUMO energy level of organophosphates through metal ions with an inert electron pair.For the first time,the P=O of phytate(PA),N,N,N’,N’-ethylenediaminetetrakis(methylene phytate)(EDTMP),and diethylenetriaminepentakis(methyl phytate)(DTPMP) is activated by lead/bismuth(with 6s2electron pair) to storage Li/Na/K ions reversibly.Typically,density functional theory calculations indicate that the LUMO energy of Bi-PA is greatly reduced from-0.99(PA) to-4.61 eV,which shows the first discharge capacity of 173,182 and 206mAh·g-1and the reversibly capacity of 102,102 and 101mAh·g-1with the discharge platform of 2.4,2.1 and 2.4 V for Li/Na/K-ion battery cathodes,respectively.Similarly,with proper LUMO energy level,Pb-PA(-4.63 eV),Pb-EDTMP(-3.71 eV),and Pb-DTPMP(-4.45 eV) all exhibit admirable performance.This unique strategy of organic materials to alkali-metal-ion battery cathodes offers a new avenue for future energy storage systems.
文摘To increase the current density of the hole only device, 1, 4, 5, 8, 9, 11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) material has been inserted in the device at the indium tin oxide (ITO)/organic interface. Since HATCN molecule can withdraw electrons, it can alter electronic properties of the electrodes and hence inserted between the organic/metal interfaces. This paper deals with the optimization of the thickness of organic-metal layers to enhance the efficiency. Also, efforts have been made to increase the current density and reduce the operating voltage of the device. The material 2, 7-bis [N, N-bis (4- methoxy-phenyl) amino]-9, 9-spirobifluorene (Meo-Spiro-TPD) is used to simulate the hole only device because it is a thermally stable hole transport material. Simulated results shows that better current density values can be achieved compared to fabricated one by optimizing the organic metal layer thickness. The best optimized layer thickness of 22 nm for Alq3, 25 nm for *CBP doped with Ir(ppy)3, 9 nm for Meo-Spiro TPD and 4 nm for HAT-CN which results in current density of 0.12 A/cm2 with a reduction in operating voltage by approximately 2 V.
