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Improving the sensitivity of MoS2-based photodetectors by constructing semiconductor heterostructures remains a challenge. To address this issue, the effects of interlayer spacing and vertical external electric fields on the interfacial interactions and electronic properties of Zr2CO2/MoS2 heterostructures were investigated systematically by first-principles calculations. The results indicate that a stable interface with van der Waals interactions can form between Zr2CO2 and MoS2, which complies with the type-II mechanism. By applying a vertical external electric field to the Zr2CO2/MoS2 heterostructure or changing the interlayer spacing between the Zr2CO2 and MoS2 monolayers, both the band gap and heterostructure type at the Zr2CO2/MoS2 interface can be modulated efficiently. It is remarkable that the band alignment of the Zr2CO2/MoS2 heterostructure is more sensitive to the external electric field than to the interlayer spacing. When the electric field is from −0.5 to 0.5 V Å−1, the energy band of the Zr2CO2/MoS2 heterostructure changes from 0.2 to 0.3 eV with a 0.1 V Å−1 increase of electric field. The redistribution of charge density with the external electric field and interlayer coupling is revealed to account for the tunable energy bands. Therefore, the Zr2CO2/MoS2 heterostructures with van der Waals interactions possess great potential to be used in high-performance photodetectors. [ABSTRACT FROM AUTHOR]

Two dimensional (2D) heterojunction based on g‐C3N4 and CuInS2(CIS) nanosheets has been successfully constructed with the assistance of biomolecules L‐cysteine. We demonstrated that a typical p–n junction charges transfer mode of CIS/PCN (protonated g‐C3N4) can be switched to Z‐scheme transfer mode through the integration of Au by weakening the role of built‐in electric field. The morphology of CIS/Au/PCN can be well adjusted through the formation of Au−S covalent bond and the electrostatic adsorption between Au and PCN during the hydrothermal process. Furthermore, the intimate interface contact inside CIS/Au/PCN heterojunction was indeed constructed, which may promote the charges separation and transfer process at the interface as evidenced by ESR spectra and time‐resolved PL spectra. Under visible light illumination, the CIS/Au/PCN exhibited an enhanced CO (19.46 μmol/g) and CH4 (1.18 μmol/g) yield in CO2 reduction, which was about 5.04 times and 2.03 times higher than pure PCN. The composite heterojunction also showed excellent photocatalytic activity for tetracycline degradation with a 87 % degradation efficiency in 1 hour, which was 2.07 times higher than pure PCN. The experimental and theoretical calculation results demonstrated that an all‐solid‐state Z‐scheme heterojunction was formed in the CIS/Au/PCN system, which was different from the typical p–n junction charges transfer mechanism in CIS/PCN. [ABSTRACT FROM AUTHOR]

Very recently, a new kind of 2D transition metal nitride, MoSi 2 N 4 , has been attracting considerable attention due to its successful synthesis and outstanding properties. To further explore its novel properties and applications for nanodevices, we have proposed a van der Waals (vdW) heterostructure composed of MoSi 2 N 4 and Blue Phosphorus (BlueP) monolayers and systematically studied its electronic properties with first-principles calculations. The results show that the heterostructure exhibits a type-II band alignment, with the conduction band minimum (CBM) and valence band maximum (VBM) located in BlueP and MoSi 2 N 4 layers, respectively. Furthermore, the electronic properties of heterostructure are not sensitive to different stacking patterns while can be significantly modulated by applying an external electric field or a biaxial strain. When applying the electronic field, the band gap shows linear variation with the electric field, and a semiconductor-to-metal transition is observed under the strong electric field. When applying the biaxial strain, the band alignment can be transformed from type-II to type-I. This work provides theoretical guidance for design of flexible nano-electronic and optoelectronic devices based on the BlueP/MoSi 2 N 4 heterostructure. • The BlueP/MoSi 2 N 4 heterostructure exhibits a type-II band alignment. • The electronic properties of heterostructure are not sensitive to diverse stacking patterns. • The electronic properties of heterostructure can be tuned by external electric field or biaxial strain. • A semiconductor-to-metal transition takes place when applying a strong electric field. • Band alignment transition from type-II to type-I has been observed under the effect of biaxial strain. [ABSTRACT FROM AUTHOR]

• Charge redistribution on the interface formed an interfacial internal electric field. • SnO x decreased work function of Sn-BiOCl and improved its photocatalytic reducibility. • Oxygen vacancies and internal electric field synergistically improved light absorption and charge separation. • Photodegradation activity of Sn-BiOCl increased 14 times higher than that of BiOCl. Solar-to-chemical energy conversion is valuable and sustainable strategy for energy and environmental crisis through photocatalysis. The amorphous SnO x modified BiOCl (Sn-BiOCl) full-spectrum-responsive catalysts were designed and synthesized through solvothermal method. The introduced Sn regulates the growth of BiOCl to form ultrathin nanosheets with surface oxygen vacancies. And the surface modification of SnO x induces interfacial internal electric field via charge redistribution on the interface of BiOCl and SnO x to accelerate the photogenerated charge separation. The modification of SnO x decreased work function of Sn-BiOCl and thus elevated its conduction band and valence band simultaneously, leading enhanced photocatalytic reducibility with the improved generation rate of ·O 2 −. The surface SnO x and oxygen vacancies of Sn-BiOCl broadened light absorption range and enhanced photocatalytic performance synergistically, resulting in 14-fold increased photodegradation rate of phenol compared with pure BiOCl under full spectrum. This method is also able to expand to other metal ions (such as Fe3+, In3+ and Sb3+). This work provides a valuable concept in structure regulating for enhanced photocatalytic performance in the removal of organic pollutants by interfacial internal electric field and surface oxygen vacancies. [ABSTRACT FROM AUTHOR]