Sensitization of LnIII (Ln = Eu, Tb, Tm) Ion Luminescence by Functionalized Polycarbonate‐Based Materials and White Light Generation

Abstract

We prepared pyridine‐2,6‐bis(ethyl)ester [BEP] and pyridine‐2,6‐bis(diethylamide) [BDP] polymers with polycarbonate backbones by ring‐opening polymerization of the pyridine‐bis(ethyl)ester and pyridine‐bis(diethylamide) units appended to a cyclic carbonate via a glycol chain. The polymers were characterized by FTIR, NMR, UV/Vis absorption and fluorescence spectroscopy, as well as SEC, powder XRD, DSC, and TGA. The measured glass transition temperature (Tg) of the BEP polymer was shifted from –32 °C to –7 and –8 °C after coordination of the EuIII and TbIII ions, respectively. Similarly, the Tg of the BDP polymer was shifted from –13 °C to –9 and –10 °C after coordination of EuIII and TbIII ions, respectively. Both polymers sensitized LnIII‐centered emission; the BEP polymer was the most efficient at sensitizing LnIII‐centered luminescence with an emission efficiency of 30 and 31 % for the EuIII and TbIII systems, respectively, compared to the 2 % determined for both the EuIII and TbIII BDP systems. Blue emission was observed when TmIII was used, and a system with the composition BEP1Eu1.8Tb28 led to a material with CIE coordinates (0.31, 0.33), typical of white light.