Bandgap modification in 0D tellurium iodide perovskite derivatives incorporation of polyiodide species.

Halide perovskites provide a versatile platform for exploring the effect of non-covalent interactions, including halogen bonding, on material properties such as band gap, luminescence, and frontier orbital landscape. Herein we report six new zero-dimensional tellurium iodide perovskite derivatives, consisting of [TeI] octahedra charge balanced by one of several X-Py cations (X = H, Cl, Br, I, and Py = pyridinium). These compounds also feature robust halogen bonding between [TeI] octahedra and polyiodides in the form of I (1-4), I (5), or adjacent octahedra (4 and 6).