Synthesis and soft crystal structure-induced broad emission of (NH 3 C 6 H 12 NH 3 )InBr 5 ·2H 2 O.

We report a simple synthesis of a new lead-free zero-dimensional (0D) hybrid halide compound, (5P1)InBr 5 ·2H 2 O [(5P1) = NH 3 C 6 H 12 NH 3 ], which hosts isolated and distorted octahedra of [InBr 5 (H 2 O)] 2- , surrounded by bulky asymmetric organic cations [(5P1) 2+ ] and H 2 O molecules. The hybrid crystals exhibit broad self trapped excitonic (STE) emission due to strong anharmonic soft structure.