Strain Engineering The Electronic And Photocatalytic Properties Of Ws2/Blue Phosphene Van Der Waals Heterostructures

The effects of -8-8% in-plane uniaxial and biaxial strains on the electronic and photocatalytic activity of tungsten disulfide/blue phosphene (WS2/BlueP) are investigated within the framework of first-principles calculations. The most energetically stable configuration of WS2/BlueP exhibits type I band alignment with a direct band gap of 1.779 eV. Compared with WS2 and BlueP, WS2/BlueP has the strongest absorption in the entire visible light region with a red-shifted absorption edge. The in-plane -8-8% uniaxial and biaxial strains cause elastic deformation of the heterostructures. The strains can affect the band gap, band edge arrangement, band type (type-I, type-II, Z-scheme) and electron transition type (direct, indirect) of WS2/BlueP. The -2% uniaxial (or biaxial) strain can engineer the band gap to reach the maximum and achieve full water decomposition. At pH = 0, only the -2% and -4% uniaxial and -2% biaxial strained WS2/BlueP (Z-scheme) heterostructures are thermodynamically feasible, while at pH = 7, all the strained heterostructures are viable for photocatalytic water decomposition. The -2% uniaxial and biaxial strained WS2/BlueP heterostructures at pH = 0 and pH = 7 are proved to be potential candidates for achieving full water decomposition. The lower potential determining step, higher electro-chemical driving forces and lower effective mass of carriers can promote the transition performance and improve the photocatalytic efficiency. Therefore, the in-plane uniaxial and biaxial strains can effectively adjust the electronic and photocatalytic performances of the heterostructures.