Two-dimensional Janus monolayers Al2XYZ (X/Y/Z = S, Se, Te, X ≠ Y ≠ Z): first-principles insight into the photocatalytic and highly adjustable piezoelectric properties

First-principles calculations show that the photocatalytic water decomposition reaction of Janus monolayers Al 2 XYZ (X/Y/Z = S, Se, Te, X ≠ Y ≠ Z) can be carried out spontaneously under an applied potential. The Janus monolayers have highly adjustable piezoelectric properties.