Solid-state organic materials that exhibit intense luminescence
have been attracting considerable interest in various fields.1−7
Among such materials, those displaying color-tunable emissions8−
16 are especially targeted in order for possible
applications such as new types of light sources, photoelectronic
materials, and sensor devices. The ability to tune the
luminescence properties of these materials by exploiting
molecular packing effects, rather than synthetic modifications
of chemical structure, has been studied extensively,15,16
although for the most part, the range of emission colors has
been limited. A straightforward and effective way to achieve
considerable variation in emission color is to combine materials
with differing luminescence bands. This approach has already
been applied for most known white-light-luminescent materials
using species that exhibit short-wavelength and long-wavelength
visible luminescence.17,18 However, the design of such
multicomponent solid-phase systems can be fraught with
complications arising from unfavorable resonance energy
transfer and intermolecular interactions among other factors.19
The above-discussed problems can be circumvented by lowenergy
emission called the excited-state intramolecular proton