Hydrostatic pressure provides an efficient way to tune and optimize the properties of solid materials without chang-ing their composition.In this work,we investigate the electronic,optical,and mechanical properties of...Hydrostatic pressure provides an efficient way to tune and optimize the properties of solid materials without chang-ing their composition.In this work,we investigate the electronic,optical,and mechanical properties of antiperovskite X_(3)NP(X^(2+)=Ca,Mg)upon compression by first-principles calculations.Our results reveal that the system is anisotropic,and the lat-tice constant a of X_(3)NP exhibits the fastest rate of decrease upon compression among the three directions,which is different from the typical Pnma phase of halide and chalcogenide perovskites.Meanwhile,Ca_(3)NP has higher compressibility than Mg_(3)NP due to its small bulk modulus.The electronic and optical properties of Mg_(3)NP show small fluctuations upon compression,but those of Ca_(3)NP are more sensitive to pressure due to its higher compressibility and lower unoccupied 3d orbital energy.For example,the band gap,lattice dielectric constant,and exciton binding energy of Ca_(3)NP decrease rapidly as the pressure increases.In addition,the increase in pressure significantly improves the optical absorption and theoretical conversion effi-ciency of Ca_(3)NP.Finally,the mechanical properties of X_(3)NP are also increased upon compression due to the reduction in bond length,while inducing a brittle-to-ductile transition.Our research provides theoretical guidance and insights for future experi-mental tuning of the physical properties of antiperovskite semiconductors by pressure.展开更多
Since their seminal discovery in 2011,two-dimensional(2D)transition metal carbides/nitrides known as MXenes,that constitute a large family of 2D materials,have been targeted toward various applications due to their ou...Since their seminal discovery in 2011,two-dimensional(2D)transition metal carbides/nitrides known as MXenes,that constitute a large family of 2D materials,have been targeted toward various applications due to their outstanding electronic properties.MXenes functioning as co-catalyst in combination with certain photocatalysts have been applied in photocatalytic systems to enhance photogenerated charge separation,suppress rapid charge recombination,and convert solar energy into chemical energy or use it in the degradation of organic compounds.The photocatalytic performance greatly depends on the composition and morphology of the photocatalyst,which,in turn,are determined by the method of preparation used.Here,we review the four different synthesis methods(mechanical mixing,self-assembly,in situ decoration,and oxidation)reported for MXenes in view of their application as co-catalyst in photocatalysis.In addition,the working mechanism for MXenes application in photocatalysis is discussed and an outlook for future research is also provided.展开更多
Chlorophylls(Chls), and associated chlorophyll derivatives, are one of the oldest, most versatile organic semiconductors found in nature. Herein, we present two easily semi-synthesized chlorophyll derivatives, namely,...Chlorophylls(Chls), and associated chlorophyll derivatives, are one of the oldest, most versatile organic semiconductors found in nature. Herein, we present two easily semi-synthesized chlorophyll derivatives, namely, chlorin e6 trimethyl ester(Ce6Me3) and its copper complex(Cu–Ce6 Me3), as the p-type dopants for organic semiconductors and their impact in organic solar cells(OSCs). In our study, both Chls showed intense Soret and Q y bands in the UV-visible spectra, leading to an effect means for capturing solar light and energy. Chls also exhibited high carrier mobility owing to the partial formation of aggregates through the spin-coating process. Using Chls, we fabricated OSCs in both planar-heterojunction(PHJ) and bulkheterojunction(BHJ) solar cell configurations, together with C70/PC70 BM as electron acceptors. In PHJ solar cells, we received solar power conversion efficiencies(PCEs) of only 0.85% and 0.93% for Cu–Ce6 Me 3-and Ce6Me3-based devices, respectively, with the thickness of the donor layer at 5 nm. In BHJ cells, we achieved much higher PCEs of 1.53% and 2.05% for Cu–Ce6Me3 :PC 70 BM and Ce6Me3 :PC 70 BM respectively, where both blending ratios were set to 1:8. The improvement on PCE in BHJ cells may be attributed to the better charge separation increase at the donor–acceptor interface.展开更多
基金supported by the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant No. KJQN202100626)the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant No. KJQN202200619)+3 种基金supported by Beijing Institute of Technology Research Fund Program for Young Scholars (Grant No. XSQD-202222008)the support from the National Natural Science Foundation of China (Grant No. 12204081)the Natural Science Foundation of Chongqing (Grant No. 2022NSCQ-MSX2540)supported by TianHe Qingsuo Project-spec ial fund project
文摘Hydrostatic pressure provides an efficient way to tune and optimize the properties of solid materials without chang-ing their composition.In this work,we investigate the electronic,optical,and mechanical properties of antiperovskite X_(3)NP(X^(2+)=Ca,Mg)upon compression by first-principles calculations.Our results reveal that the system is anisotropic,and the lat-tice constant a of X_(3)NP exhibits the fastest rate of decrease upon compression among the three directions,which is different from the typical Pnma phase of halide and chalcogenide perovskites.Meanwhile,Ca_(3)NP has higher compressibility than Mg_(3)NP due to its small bulk modulus.The electronic and optical properties of Mg_(3)NP show small fluctuations upon compression,but those of Ca_(3)NP are more sensitive to pressure due to its higher compressibility and lower unoccupied 3d orbital energy.For example,the band gap,lattice dielectric constant,and exciton binding energy of Ca_(3)NP decrease rapidly as the pressure increases.In addition,the increase in pressure significantly improves the optical absorption and theoretical conversion effi-ciency of Ca_(3)NP.Finally,the mechanical properties of X_(3)NP are also increased upon compression due to the reduction in bond length,while inducing a brittle-to-ductile transition.Our research provides theoretical guidance and insights for future experi-mental tuning of the physical properties of antiperovskite semiconductors by pressure.
基金supported by the National Natural Science Foundation of China(No.11574111 and No.11974129 to X.-F.W.)“the Fundamental Research Funds for the Central Universities.”.
文摘Since their seminal discovery in 2011,two-dimensional(2D)transition metal carbides/nitrides known as MXenes,that constitute a large family of 2D materials,have been targeted toward various applications due to their outstanding electronic properties.MXenes functioning as co-catalyst in combination with certain photocatalysts have been applied in photocatalytic systems to enhance photogenerated charge separation,suppress rapid charge recombination,and convert solar energy into chemical energy or use it in the degradation of organic compounds.The photocatalytic performance greatly depends on the composition and morphology of the photocatalyst,which,in turn,are determined by the method of preparation used.Here,we review the four different synthesis methods(mechanical mixing,self-assembly,in situ decoration,and oxidation)reported for MXenes in view of their application as co-catalyst in photocatalysis.In addition,the working mechanism for MXenes application in photocatalysis is discussed and an outlook for future research is also provided.
基金partially supported by the Natural Science Foundation of China (No. 11574111 to X-F.W.)JSPS KAKENHI Grant Number JP16K05826 in Scientific Research (C) (to S.S.)+1 种基金supported by the Natural Science Foundation of Jilin Province (No. 20160101303JC , 20180101238JC , 20170204076GX , 20180101006JC to C.S.)Post-Doctoral Innovative Talent Support Program (BX20180127 to S.W.)
文摘Chlorophylls(Chls), and associated chlorophyll derivatives, are one of the oldest, most versatile organic semiconductors found in nature. Herein, we present two easily semi-synthesized chlorophyll derivatives, namely, chlorin e6 trimethyl ester(Ce6Me3) and its copper complex(Cu–Ce6 Me3), as the p-type dopants for organic semiconductors and their impact in organic solar cells(OSCs). In our study, both Chls showed intense Soret and Q y bands in the UV-visible spectra, leading to an effect means for capturing solar light and energy. Chls also exhibited high carrier mobility owing to the partial formation of aggregates through the spin-coating process. Using Chls, we fabricated OSCs in both planar-heterojunction(PHJ) and bulkheterojunction(BHJ) solar cell configurations, together with C70/PC70 BM as electron acceptors. In PHJ solar cells, we received solar power conversion efficiencies(PCEs) of only 0.85% and 0.93% for Cu–Ce6 Me 3-and Ce6Me3-based devices, respectively, with the thickness of the donor layer at 5 nm. In BHJ cells, we achieved much higher PCEs of 1.53% and 2.05% for Cu–Ce6Me3 :PC 70 BM and Ce6Me3 :PC 70 BM respectively, where both blending ratios were set to 1:8. The improvement on PCE in BHJ cells may be attributed to the better charge separation increase at the donor–acceptor interface.
