Luminescent and thermal properties of a novel red-emitting silicon fluoride acrylate-Eu(III) copolymer for white LEDs

A red-emitting silicon fluoride acrylate (SFA)-Eu(III) copolymer was prepared based on water-in-oil emulsion polymerization method. Its photoluminescence including the temporal decay was studied in addition to the thermal properties. Of the emissions due to the D-5(0) --> F-7(J) (J = 0-4) transitions of Eu3+ ions, an intense red emission due to D-5(0) --> F-7(2) transition was observed at 618 nm under the 395 nm excitation, together with a weak D-5(0) --> F-7(0) emission at 580 nm. Compared with some commercial phosphor, the SFA-Eu(III) copolymer also have a higher QE value. From the optical properties it was suggested that Eu3+ ions were located at the disordered non-inversion Eu3+ sites in the copolymer. The glass transition temperature (T-g) was estimated about -51.5 degrees C from a differential scanning calorimetric curve, while chemical decomposition was estimated to start from 385 degrees C from a thermogravimetry analysis curve. Taking into account the thermal stability in a wide temperature range from -51.5 degrees C to 385 degrees C, the SFA-Eu(III) copolymer is expected to act as a potential red component for near-UV excited white LEDs. (C) 2014 Elsevier B.V. All rights reserved.