Synthetic Control of Excited-State Dynamics in Low Dimensional Metal Halide Hybrids

Organic metal halide hybrids have recently emerged as a highly promising class of functional materials for a variety of optoelectronic applications. The exceptional structural tunability has been demonstrated for this class of materials with different types of crystallographic structures. Using appropriate organic moieties and metal halide salts, organic metal halide hybrids with three- (3D), two- (2D), one- (1D), and zero-dimensional (0D) structures at the molecular level have been developed and studied. Despite the remarkable progress realized in the 3D and 2D metal halide structures, 1D and 0D structures with unique properties were left significantly underexplored. Lowering the dimensionality to 0D with the individual polyhedral metal halides separated from each other allows the bulk crystals to exhibit intrinsic properties (e.g. efficient Stokes-shifted broadband emissions) of their building blocks, which is significantly different from their counterparts with higher dimensionalities. We have demonstrated the capability to synthetically control the photophysical properties of this class of 0D hybrids by different strategies, such as tuning of their compositions, metal halide geometries, and molecular environments. The excitement about the recent developments lies not only in the specific achievements but also in what these materials represent in terms of a new paradigm in materials design. The application of low dimensional hybrids as single-component phosphor in optically pumped white LEDs will also be discussed.