In-situ topotactic construction of novel rod-like Bi_(2)S_(3)/Bi_(5)O_(7)I p-n heterojunctions with highly enhanced photocatalytic activities

In this work,a novel Bi_(2)S_(3)/Bi_(5)O_(7)I p-n heterojunction with three-dimensional rod-like nanostructure was successfully constructed through an in-situ topotactic ion exchange approach.A possible evolution mech-anism from Bi_(5)O_(7)I nanobelts(NBs)into Bi_(2)S_(3)/Bi_(5)O_(7)I rod-like heterostructures(BSI RHs)was proposed,depicting the self-assembly process of internal Bi_(5)O_(7)I NBs and outside networks interwoven by Bi_(2)S_(3)nanorods(NRs),which abided by the Ostwald ripening and epitaxial growth.Owing to the formation of p-n heterojunction and rich oxygen vacancies(OVs),the visible-light absorption ability and separation of photogenerated charge carriers of BSI RHs were highly promoted,leading to a greatly improved photocatalytic ability than that of Bi_(2)S_(3)and Bi_(5)O_(7)I.BSI-1 exhibited the strongest photocatalytic performance,and almost all rhodamine B(RhB)and Pseudomonas aeruginosa(P.aeruginosa)can be thoroughly removed within 90 min.Moreover,a possible photocatalytic mechanism of BSI RHs was proposed based on the tests of active species trapping,electron spin resonance(ESR),photoelectrochemistry(PEC),and photoluminescence(PL)combined with the density functional theory(DFT)simulated computation,vali-dating the dominating roles of·O_(2)^(−)and h+during the photocatalytic process.This work is expected to motivate further efforts for developing novel heterostructures with highly efficient photocatalytic performances,which presents a promising application prospect in the fields of energy and environment.

Flexoelectricity Driven Fano Resonance in Slotted Carbon Nanotubes for Decoupled Multifunctional Sensing

Multifunctionality,interference-free signal readout,and quantum effect are important considerations for flexible sensors equipped within a single unit towards further miniaturization.To address these criteria,we present the slotted carbon nanotube(CNT)junction features tunable Fano resonance driven by flexoelectricity,which could serve as an ideal multimodal sensory receptor.Based on extensive ab initio calculations,we find that the effective Fano factor can be used as a temperature-insensitive extrinsic variable for sensing the bending strain,and the Seebeck coefficient can be used as a strain-insensitive intrinsic variable for detecting temperature.Thus,this dual-parameter permits simultaneous sensing of temperature and strain without signal interference.We further demonstrate the applicability of this slotted junction to ultrasensitive chemical sensing which enables precise determination of donor-type,acceptor-type,and inert molecules.This is due to the enhancement or counterbalance between flexoelectric and chemical gating.Flexoelectric gating would preserve the electron–hole symmetry of the slotted junction whereas chemical gating would break it.As a proof-of-concept demonstration,the slotted CNT junction provides an excellent quantum platform for the development of multistimuli sensation in artificial intelligence at the molecular scale.

Dual response of graphene-based ultra-small molecular junctions to defect engineering

It has been reported that N and B doping induce a quasi-bound state that suppresses the conduction in graphene nanoribbon （GNR）-based junctions, while an H defect or a pyridine-like N-atom （PN） substitution at the edge of the GNR does not affect the transmission close to the Fermi energy. However, these results may vary when the size of the functional unit of the GNR junction decreases to a molecular level. In this study, a defect is introduced to a test-bed architecture consisting of a polyacene bridging two zigzag GNR electrodes, which changes the molecular state alignment and coupling to the electrode states, and varies the equivalence between two eigen-channels at the Fermi level. It is revealed that B and N atom substitution, and H defects play a dual role in the molecular conductance, whereas the PN substitution acts as an ineffective dopant. The results obtained from density functional theory combined with the non-equilibrium Green＇s function method aid in determining the optimal design for the GNR-based ultra-small molecular devices via defect engineering.

1D Bi_(2)S_(3) nanorods modified 2D BiOI nanoplates for highly efficient photocatalytic activity:Pivotal roles of oxygen vacancies and Z-scheme heterojunction

In this study,a novel Bi_(2)S_(3)/BiOI Z-scheme photocatalyst with 3D porous hierarchical network-like heterostructure(BSBI NHs)and rich oxygen vacancies(OVs)was fabricated by a facile ion exchange method followed by the in-situ growth process.A possible formation mechanism of BSBI NHs was studied,showing the self-assembled process of in-situ interwoven growth of 1D Bi_(2)S_(3) nanorods(NRs)on the surface of 2D BiOI disk-like nanoplates(NPs),which followed the Ostwald ripening and epitaxial growth.The modification of BiOI NPs by Bi_(2)S_(3) NRs brought about the formation of Z-scheme heterojunction and massive OVs,which improved the visible-light response property and promoted the separation of photoexcited charge carriers of BSBI NHs.BSBI NHs exhibited a significantly enhanced photocatalytic activity compared with Bi_(2)S_(3) and BiOI,and BSBI-1 can remove almost all bacteria and Rhodamine B(RhB)after 60 min visible light illumination.In addition,the photocatalytic mechanism was studied and speculated based on the tests of active species capture,electron spin resonance(ESR),and density functional theory(DFT)simulation calculation,proving the primary roles of·OH,·O_(2)^(-)and h^(+)during the photocatalytic reaction.This work provides new insights into the design and exploitation of novel heterojunctions with highly efficient photocatalytic performances for environmental remediation applications.

Flexoelectricity Driven Fano Resonance in Slotted Carbon Nanotubes for Decoupled Multifunctional Sensing

Mulifunctionality,interference fre signal readout,and quantum eft are important considerations for flexible sensors equipped within a single unit towards further miniaturization.To address these criteria,we present the slotted carbon nanotube(CNT)junction features lunable Fano resonance driven by flexoelectricity,which could serve as an ideal multimodal sensory receptor.Based on extensive ab initio calculations,we find that the efective Fano factor can be used as a temperature insensitive extrinsic variable for sensing the bending strain,and the Seebeck cefficient can be used as a strain-insensitive intrinsic variable for detecting temperalure.Thus,this dual parameter permits simultaneous sensing of temperature and strain without signal interference.We further demonstrale the applcability of this slotted junction to ultrasensitive chemical sensing which enables precise determination of donor type.acceptor type.and inert molecules.This is due to the enhancement or counterbalance between flexoelectric and chemical gating.Flexoelectric gating would preserve the electron-hole symmetry of the slotted junction whereas chemical gating would break it.As a proof-of-concept demonstration,the slotted CNT junction provides an excellent quantum platform for the development of mulistimuli sensation in artificial itelligence at the molecular scale.