A Family of Highly Efficient CuI-Based Lighting Phosphors Prepared by a Systematic, Bottom-up Synthetic Approach

Copper­(I) iodide (CuI)-based inorganic–organic
hybrid materials
in the general chemical formula of CuI­(L) are well-known for their
structural diversity and strong photoluminescence and are therefore
considered promising candidates for a number of optical applications.
In this work, we demonstrate a systematic, bottom-up precursor approach
to developing a series of CuI­(L) network structures built on CuI rhomboid
dimers. These compounds combine strong luminescence due to the CuI
inorganic modules and significantly enhanced thermal stability as
a result of connecting individual building units into robust, extended
networks. Examination of their optical properties reveals that these
materials not only exhibit exceptionally high photoluminescence performance
(with internal quantum yield up to 95%) but also that their emission
energy and color are systematically tunable through modification of
the organic component. Results from density functional theory calculations
provide convincing correlations between these materials’ crystal
structures and chemical compositions and their optophysical properties.
The advantages of cost-effective, solution-processable, easily scalable
and fully controllable synthesis as well as high quantum efficiency
with improved thermal stability, make this phosphor family a promising
candidate for alternative, RE-free phosphors in general lighting and
illumination. This solution-based precursor approach creates a new
blueprint for the rational design and controlled synthesis of inorganic–organic
hybrid materials.