Highly Luminescent Copper Iodide Cluster Based Inks with Photoluminescence Quantum Efficiency Exceeding 98%

Highly
luminescent inks are desirable for various applications
such as decorative coating, art painting, and anticounterfeiting,
to name a few. However, present inks display low photoluminescent
efficiency requiring a strong excitation light to make them glow.
Here, we report a highly luminescent ink based on the copper-iodide/1-Propyl-1,4-diazabicyclo[2.2.2]­octan-1-ium
(Cu4I6(pr-ted)2) hybrid cluster with
a quantum efficiency exceeding 98%. Under the interaction between
the Cu4I6(pr-ted)2 hybrid cluster
and polyvinylpyrrolidone (PVP), the highly luminescent Cu4I6(pr-ted)2/PVP ink can be facilely prepared
via the one-pot solution synthesis. The obtained ink exhibits strong
green light emission that originates from the efficient phosphorescence
of Cu4I6(pr-ted)2 nanocrystals. Attractively,
the ink displays high conversion efficiency for the ultraviolet light
to bright green light emission due to its wide Stokes shift, implying
great potential for anticounterfeiting and luminescent solar concentrator
coating.