Band Structure Engineering of 2D Heterotriangulene Polymers by Incorporating Acetylenic Linkages for Photocatalytic Hydrogen Production

By performing first-principles calculations, we propose to introduce acetylenyl (−CC−) into the honeycomb kagome lattices of heterotriangulenes (HT)-based two-dimensional (2D) polymers to construct 2D HT-polyynes with tunable electronic and optical properties for photocatalysis. It is found that the band gap can be effectively reduced to a moderate value of around 2.00 eV by increasing the number of −CC– (n = 1, 2, 3) in the skeletons, contributing to enhanced light-harvesting ability in the visible range of the spectrum. Interestingly, the band edges of 2D HT-polyynes shift upward after incorporating with −CC– and then shift downward when the number of incorporated −CC– increases from 1 to 2 and 3. Possessing moderate band gap and matching band-edge alignments, high carrier mobility, and pronounced light-harvesting capability, the designed 2D HT-polyynes are predicted to be potential candidates for photocatalytic hydrogen production.