In inverted perovskite solar cells (PSCs),effective modification of the interface between the metalcathode and electron transport layer (ETL) is crucial forachieving high performance and stability. Herein, sulfonatedb...In inverted perovskite solar cells (PSCs),effective modification of the interface between the metalcathode and electron transport layer (ETL) is crucial forachieving high performance and stability. Herein, sulfonatedbathocuproine, commonly known as disodium bathocuproinedisulfonate (BCDS), was employed as a cathode buffer layerto address the interfacial issues at the [6,6]-phenyl-C61-butyricacid methyl ester (PCBM)/Ag interface. BCDS possesses theability to form coordinate bonds with Ag electrodes. Theutilization of the BCDS buffer layer enhanced the chargeextraction capability at the cathode interface whilesimultaneously achieving interfacial defect passivation,improving interfacial contact and increasing the built-in electricfield. Consequently, a power conversion efficiency (PCE) of25.06% was achieved. Furthermore, owing to the excellent filmforminguniformity of BCDS on PCBM, the stability of thedevice was also improved. After storage in dry air for morethan 2000 h, the device maintained 96% of its initial efficiency. This work underscores the remarkable potential of tailoringcoordination groups to enhance charge extraction efficiency at the ETL-cathode interface, unveiling a promising newfrontier in buffer layer development and performance optimization strategies for PSCs.展开更多
Birefringent crystals are crucial for the miniaturization of optical devices.Phosphate crystals,characterized by their highly symmetrical tetrahedral structures,exhibit excellent stability and wide optical bandgaps.Ho...Birefringent crystals are crucial for the miniaturization of optical devices.Phosphate crystals,characterized by their highly symmetrical tetrahedral structures,exhibit excellent stability and wide optical bandgaps.However,their intrinsic symmetry typically results in low birefringence,with most phosphate compounds having birefringence values below 0.1.Efforts to enhance birefringence by introducing highly anisotropic ions and groups have been impeded by the tetrahedral coordination of phosphate,which often leads to the cancellation of anisotropic effects.To address this challenge,we propose an approach that leverages the synergistic modification of multiple functional groups to disrupt the anisotropic cancellation in phosphate crystals and significantly enhance their birefringence.Specifically,we incorporate Te(IV),which features stereo-chemically active lone pairs,and Hg(II),known for its high polarizability and deformability,into the phosphate system.We synthesized a novel phosphate compound,Hg_(2)(HTe_(2)O_(5))(PO_(4)),which exhibits a calculated birefringence of 0.162 at 546 nm and a measured birefringence of 0.168 at 546 nm.This value is comparable to that of the commercial birefringent material CaCO_(3)(Δn=0.172@546 nm)and surpasses most previously reported phosphate materials.Additionally,Hg_(2)(HTe_(2)O_(5))(PO_(4))demonstrates a wide bandgap and excellent stability.Using the PAWED method,we determined that the significant birefringence of Hg_(2)(HTe_(2)O_(5))(PO_(4))is primarily due to the combined contributions of the HgO7 polyhedra(19.86%),PO_(4) tetrahedra(29.17%),and Te_(2)O_(5) groups(47.40%).Our work demonstrates that the synergistic modification of multiple functional groups is an effective strategy for enhancing the birefringence of tetrahedral compounds,providing a new pathway for the development of high-performance birefringent materials.展开更多
The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits ...The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits moderate photocatalytic activity due to insufficient active sites.In this study,cyano‐modified porous g‐C_(3)N_(4)nanosheets(MCN‐0.5)were synthesized through molecular self‐assembly and alkali‐assisted strategies.The cyano group acted as the active site of the photocatalytic reaction,because the good electron‐withdrawing property of the cyano group promoted carrier separation.Benefiting from the effect of the active sites,MCN‐0.5 exhibited significantly enhanced photocatalytic activity for CO2 reduction under visible light irradiation.Notably,the photocatalytic activity of MCN‐0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid(HCl)treatment,further verifying the role of cyano groups as active sites.The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction.Furthermore,the controlled experiments showed that g‐C_(3)N_(4)grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity,which proved the versatility of the strategy for enhancing the activity of g‐C_(3)N_(4)via cyano group modification.In situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO2 reduction by cyano‐modified g‐C_(3)N_(4).This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.展开更多
Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to ...Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs＇ Brunauer-EmmettTeller（BET） surface area, surface groups, and silver coating morphology were characterized by N2 adsorption, elemental analysis（EA）, X-ray photoelectron spectroscopy（XPS）, and scanning electron microscopy（SEM）, respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO3 treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, Na OH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while Na OH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag（NH3）2]NO3 concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on Na OH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.展开更多
In the present investigation, novel poly（amid-imide）/zinc oxide nanocomposites（PAI/Zn O NCs） containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles（Zn ...In the present investigation, novel poly（amid-imide）/zinc oxide nanocomposites（PAI/Zn O NCs） containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles（Zn O NPs） were successfully prepared via the ex situ method. Poly（amid-imide）（PAI） was prepared by direct polycondensation of 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole（DCA） with 5-（2-benzimidazole）-1,3-phenylenediamine（DAMI） and provided the polymeric matrix with well-designed groups. The surface of Zn O NPs was functionalized with 3-aminopropyltriethoxysilane（APS） coupling agent to have a better dispersion and enhancing possible interactions of NPs with functional groups of polymer matrix. The amount of APS bonded to the Zn O surface was determined by thermogravimetric analysis. PAI/Zn O nanocomposites were characterized by Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, and scanning electron microscopy（SEM）. SEM analysis showed that the modified Zn O nanoparticles were homogeneously dispersed in polymer matrix. In addition, TGA data indicated an enhancement of thermal stability of the nanocomposite compared with the neat polymer.展开更多
基金supported financially by the National Key R&D Program of China(No.2023YFE0111500)the National Natural Science Foundation of China(Nos.62204222,52103237,52321006,T2394480 and T2394484).
文摘In inverted perovskite solar cells (PSCs),effective modification of the interface between the metalcathode and electron transport layer (ETL) is crucial forachieving high performance and stability. Herein, sulfonatedbathocuproine, commonly known as disodium bathocuproinedisulfonate (BCDS), was employed as a cathode buffer layerto address the interfacial issues at the [6,6]-phenyl-C61-butyricacid methyl ester (PCBM)/Ag interface. BCDS possesses theability to form coordinate bonds with Ag electrodes. Theutilization of the BCDS buffer layer enhanced the chargeextraction capability at the cathode interface whilesimultaneously achieving interfacial defect passivation,improving interfacial contact and increasing the built-in electricfield. Consequently, a power conversion efficiency (PCE) of25.06% was achieved. Furthermore, owing to the excellent filmforminguniformity of BCDS on PCBM, the stability of thedevice was also improved. After storage in dry air for morethan 2000 h, the device maintained 96% of its initial efficiency. This work underscores the remarkable potential of tailoringcoordination groups to enhance charge extraction efficiency at the ETL-cathode interface, unveiling a promising newfrontier in buffer layer development and performance optimization strategies for PSCs.
基金supported by the National Natural Science Foundation of China(Grant No.:22475215 and 22031009)the Natural Science Foundation of Fujian Province(Grant No.:2023J01216,2024J010039)+1 种基金the Self-deployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences(No.CXZX-2022-GH06)We are grateful for the birefringence measurements provided by Dr Hongyuan Sha at FJIRSM.
文摘Birefringent crystals are crucial for the miniaturization of optical devices.Phosphate crystals,characterized by their highly symmetrical tetrahedral structures,exhibit excellent stability and wide optical bandgaps.However,their intrinsic symmetry typically results in low birefringence,with most phosphate compounds having birefringence values below 0.1.Efforts to enhance birefringence by introducing highly anisotropic ions and groups have been impeded by the tetrahedral coordination of phosphate,which often leads to the cancellation of anisotropic effects.To address this challenge,we propose an approach that leverages the synergistic modification of multiple functional groups to disrupt the anisotropic cancellation in phosphate crystals and significantly enhance their birefringence.Specifically,we incorporate Te(IV),which features stereo-chemically active lone pairs,and Hg(II),known for its high polarizability and deformability,into the phosphate system.We synthesized a novel phosphate compound,Hg_(2)(HTe_(2)O_(5))(PO_(4)),which exhibits a calculated birefringence of 0.162 at 546 nm and a measured birefringence of 0.168 at 546 nm.This value is comparable to that of the commercial birefringent material CaCO_(3)(Δn=0.172@546 nm)and surpasses most previously reported phosphate materials.Additionally,Hg_(2)(HTe_(2)O_(5))(PO_(4))demonstrates a wide bandgap and excellent stability.Using the PAWED method,we determined that the significant birefringence of Hg_(2)(HTe_(2)O_(5))(PO_(4))is primarily due to the combined contributions of the HgO7 polyhedra(19.86%),PO_(4) tetrahedra(29.17%),and Te_(2)O_(5) groups(47.40%).Our work demonstrates that the synergistic modification of multiple functional groups is an effective strategy for enhancing the birefringence of tetrahedral compounds,providing a new pathway for the development of high-performance birefringent materials.
文摘The active site amount of photocatalysts,being the key factors in photocatalytic reactions,directly affects the photocatalytic performance of the photocatalyst.Pristine graphitic carbon nitride(g‐C_(3)N_(4))exhibits moderate photocatalytic activity due to insufficient active sites.In this study,cyano‐modified porous g‐C_(3)N_(4)nanosheets(MCN‐0.5)were synthesized through molecular self‐assembly and alkali‐assisted strategies.The cyano group acted as the active site of the photocatalytic reaction,because the good electron‐withdrawing property of the cyano group promoted carrier separation.Benefiting from the effect of the active sites,MCN‐0.5 exhibited significantly enhanced photocatalytic activity for CO2 reduction under visible light irradiation.Notably,the photocatalytic activity of MCN‐0.5 was significantly reduced when the cyano groups were removed by hydrochloric acid(HCl)treatment,further verifying the role of cyano groups as active sites.The photoreduction of Pt nanoparticles provided an intuitive indication that the introduction of cyano groups provided more active sites for the photocatalytic reaction.Furthermore,the controlled experiments showed that g‐C_(3)N_(4)grafted with cyano groups using melamine as the precursor exhibited enhanced photocatalytic activity,which proved the versatility of the strategy for enhancing the activity of g‐C_(3)N_(4)via cyano group modification.In situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations were used to investigate the mechanism of enhanced photocatalytic activity for CO2 reduction by cyano‐modified g‐C_(3)N_(4).This work provides a promising route for promoting efficient solar energy conversion by designing active sites in photocatalysts.
基金Funded by the Interdisciplinary Program of Shanghai Jiao Tong University(YG2016MS24)
文摘Silver coatings on the exterior surface of monolithic activated carbon（MAC） with different morphology were prepared by directly immersing MAC into [Ag（NH3）2]NO3 solution. Acid and base treatments were employed to modify the surface oxygenic groups of MAC, respectively. The MACs＇ Brunauer-EmmettTeller（BET） surface area, surface groups, and silver coating morphology were characterized by N2 adsorption, elemental analysis（EA）, X-ray photoelectron spectroscopy（XPS）, and scanning electron microscopy（SEM）, respectively. The coating morphology was found to be closely related to the surface area and surface functional groups of MAC. For a raw MAC which contained a variety of oxygenic groups, HNO3 treatment enhanced the relative amount of highly oxidized groups such as carboxyl and carbonates, which disfavored the deposition of silver particles. By contrast, Na OH treatment significantly improved the amount of carbonyl groups, which in turn improved the deposition amount of silver. Importantly, lamella silver was produced on raw MAC while Na OH treatment resulted in granular particles because of the capping effect of carbonyl groups. At appropriate [Ag（NH3）2]NO3 concentrations, silver nanoparticles smaller than 100 nm were homogeneously dispersed on Na OH-treated MAC. The successful tuning of the size and morphology of silver coatings on MAC is promising for novel applications in air purification and for antibacterial or aesthetic purposes.
基金financially supported by the Research Council of Hormozgan University
文摘In the present investigation, novel poly（amid-imide）/zinc oxide nanocomposites（PAI/Zn O NCs） containing benzoxazole and benzimidazole pendent groups with different amounts of modified zinc oxide nanoparticles（Zn O NPs） were successfully prepared via the ex situ method. Poly（amid-imide）（PAI） was prepared by direct polycondensation of 2-[3,5-bis（N-trimellitimidoyl）phenyl]benzoxazole（DCA） with 5-（2-benzimidazole）-1,3-phenylenediamine（DAMI） and provided the polymeric matrix with well-designed groups. The surface of Zn O NPs was functionalized with 3-aminopropyltriethoxysilane（APS） coupling agent to have a better dispersion and enhancing possible interactions of NPs with functional groups of polymer matrix. The amount of APS bonded to the Zn O surface was determined by thermogravimetric analysis. PAI/Zn O nanocomposites were characterized by Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, and scanning electron microscopy（SEM）. SEM analysis showed that the modified Zn O nanoparticles were homogeneously dispersed in polymer matrix. In addition, TGA data indicated an enhancement of thermal stability of the nanocomposite compared with the neat polymer.
