Unlocking Multicolor Emissions in the Crystalline State through Dimerization and Configurational Transformation of a Single Fluorophore

Multicolor luminescent materials with tunable properties
hold great
promise for a wide range of applications in materials science. Unfortunately,
the conventional approach to achieving multicolor emissions by blending
multiple types of fluorophores is hindered by limitations, notably,
spectral instability, aggregation-caused quenching, and energy transfer.
The pursuit of multicolor emissions from a single type of fluorophore
in the solid state has, until now, remained a formidable challenge.
In this study, we have introduced N,N′-diphenyl
dihydrodibenzo[a,c]-phenazines (DPAC),
augmented with two o-carboranyl units, to create
a novel fluorophore CbDPAC. The CbDPAC crystal exhibits three distinct
emission bands peaking at 405, 470, and 620 nm, respectively, arising
from a rich intermolecular interaction network that generates novel
emission centers, such as conformational isomers and excimers. This
work inspires the rational molecular engineering of smart fluorophores
with tailorable properties and inaugurates diverse possibilities for
stimuli-responsive luminescent technologies.