Metal halide clusters emit highly efficient blue light

A single-crystalline assembly of clusters emits at an 83% photoluminescence quantum efficiency at 470 nm.

A research team from Florida State University (Tallahassee, FL) and the University of Southern California (Los Angeles, CA) has discovered that a certain organic-inorganic compound containing zero-dimensional molecular clusters emits a highly efficient blue light.1 Associate Professor of Chemistry and Biochemistry Biwu Ma has been working with an emerging class of functional materials that are organic-inorganic metal halide hybrids. A typical metal halide hybrid contains metal and halogen, and another component that can be either organic or inorganic.

Ma describes these metal halide hybrids as materials built from Lego-like pieces because they can be assembled by using the same chemical building blocks -- metal halide octahedrons. In the structure, lead chloride tetrahedrons and face-sharing lead chloride trimer clusters crystallize together with organic cations to form a periodical zero-dimensional structure.

Previously, Ma's group has reported metal halide layers, wires, and tubes using these building blocks. The newly developed single crystalline assembly of metal halide clusters has a highly efficient blue emission -- the essential color for solid-state lighting and full-color display applications. It has a photoluminescence quantum efficiency (PLQE) of around 83% at 470 nm, meaning that it could potentially be developed for use in photon-related technologies like lasers or light-emitting diodes.

"It has fantastic photophysical properties," Ma says. "This quantum efficiency is actually among the highest values reported to date for single crystalline blue light emitters."

The work is supported by the National Science Foundation and the Air Force Office of Scientific Research.



1. Chenkun Zhou et al., Journal of the American Chemical Society (2018); doi: 10.1021/jacs.8b07731.

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