All-in-One: Achieving Robust, Strongly Luminescent and Highly Dispersible Hybrid Materials by Combining Ionic and Coordinate Bonds in Molecular Crystals.

Extensive research has been pursued to develop low-cost and high-performance functional inorganic-organic hybrid materials for clean/renewable energy related applications. While great progress has been made in the recent years, some key challenges remain to be tackled. One major issue is the generally poor stability of these materials, which originates from relatively fragile/weak bonds between inorganic and organic constituents. Herein, we report a unique "all-in-one" (AIO) approach in constructing robust structures with desired properties. Such approach allows formation of both ionic and coordinate bonds within a molecular cluster, which greatly enhances structural stability while maintaining the molecular identity of the cluster and its high luminescence. The novel AIO structures are composed of various anionic (CuI) clusters and cationic N-ligands. They exhibit high luminescence efficiency, significantly improved chemical, thermal and moisture stability, and excellent solution processability. Both temperature dependent photoluminescence experiments and DFT calculations are performed to investigate the luminescence origin and emission mechanism of these materials, and their suitability as energy-saving LED lighting phosphors is assessed. This study offers a new material designing strategy that may be generalized to many other material classes.