K4Cu3(C3N3O3)2X (X = Cl, Br): strong anisotropic layered semiconductors containing mixed p–p and d–p conjugated π-bonds

Abstract

2D materials are gaining more and more interest owing to their promising applications in future electronic industry. Here, two new quasi-2D metal cyanurates, K₄Cu₃(C₃N₃O₃)₂X (X = Cl, Br), were grown and characterized for the first time. They belong to the trigonal Pm1 space group and feature an infinite layer, constructed by p–p conjugation in the (C₃N₃O₃) planar six-membered-rings and d–p conjugation in the N–Cu–N linear chains. Moreover, they are indirect semiconductors with suitable bandgaps of 3.5 eV, locating between g-C₃N₄ and h-BN. The electronic states and anisotropic optical responses were also studied through theoretical calculations.