Structural diversity and photoluminescence enhancement of indium-based hybrid metal halides

Low-dimensional organic-inorganic metal halides have attracted increasing attention for their diverse structure and excellent photoelectric properties. Here, we report two zero-dimensional indium-based halides, (C3H12N2)3In2Cl12 center dot 2 H2O ([C3H12N2]2+ is N-methylethylenediamine cation) with space group of P-1 and (C3H12N2)2InCl7 with space group of P21/c. Upon UV excitation, 1 %Sb doped (C3H12N2)3In2Cl12 center dot 2 H2O exhibits luminescence centering at 588 nm with a full width at half-maximum of 149 nm (0.527 eV), as well as a large Stokes shift of 262 nm (1.69 eV) with photoluminescence quantum yields as high as 56 %. The broad emission originates from the electron transitions of the Sb3+ 5s2 lone pair. 1 %Sb doped (C3H12N2)3In2Cl12 center dot 2 H2O exhibits more intense, broader emission and larger Stokes shift than that of 1 %Sb doped (C3H12N2)2InCl7 which is due to that the crystalline water increases the hydrogen bonding and leading to more distorted [SbCl6]3- octahedra. This work unveiled the relationship between structure and photoluminescence properties, and provide new types of organic-inorganic metal halides for potential application in light-emitting diodes.