Photoluminescence from amino-containing polymer in the presence of CO2: carbamato anion formed as a fluorophore.
Organic photoluminescent materials are important to many applications especially for diagnosis and detection, and most of organic photoluminescent materials contain fluorophores with extended conjugated structures. Recently some of amino-containing polymers without fluorophores with extended conjugated structure are observed to be photoluminescent, and one possible cause of the photoluminescence is oxidation of the amines. Here we show that photoluminescence can be produced by exposing a typical amino-containing polymer, polyethylenimine, to carbon dioxide. We demonstrate that carbamato anion formed via the reaction between the amine and carbon dioxide is a fluorophore; and the loosely-bound protonated water molecule can increase UV absorption but reduce the photoluminescence emission. Also carbamato anion shows solvent- and excitation wavelength-dependent emission of photoluminescence. The photoluminescence profile of carbamoto anion was discussed. These results will facilitate the understanding of photoluminescence observed from amino-containing materials and the design of new fluorophores.
Institute of Materials Research and Engineering, A *STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602.
Xiaoyong
X
Pan
Guan
G
Wang
Chee Leng
CL
Lay
Beng Hong
BH
Tan
Chaobin
C
He
Ye
Y
Liu