TUNABLE EMISSION IN POLY(4-VINYLPYRIDINE)-BASED GEL

We have discovered a new class of smart-gels, poly(4-vinylpyridine) (P VPy) swollen with pyridine (Py), that following photoexcitation (395, 455, 557 nm) emits three independent colors: blue, green, and red (477 , 527, 585 nm, respectively). These excitation wavelengths also induce d large reversible changes in pH and electrical conductivity. The prim ary photoexcitation paths within this photo-active gel are singlet-exc itons. The origin of this phenomenon is attributed to the combined pro perties of weak coupling via hydrogen-bonding and high polarizability. Our preliminary model suggests, that C-H ... N based Py associates ar e formed during the gelation process. Photoexcitation leads to proton transfer within three different kinds of assemblies and to a solid-sta te-like electronic behavior of the gel. This system, i.e. a photocondu cting transparent organic gel with multiple color emission, is very at tractive for a wide range of promising applications in the field of op toelectronic devices such as organic LED's and 3D holography.