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

• We firstly developed a red-emitting silicon fluoride acrylate-Eu(III) copolymer.
• SFA-Eu(III) copolymer can be excited by wavelength in near-UV and blue regions.
• Eu3+ ions occupy several disordered crystallographic sites in the copolymer.
• SFA-Eu(III) copolymer displays an ideal thermal stability and cold endurance.
• SFA-Eu(III) copolymer could be a potential red material to be used 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 5D0 → 7FJ (J = 0–4) transitions of Eu3+ ions, an intense red emission due to 5D0 → 7F2 transition was observed at 618 nm under the 395 nm excitation, together with a weak 5D0 → 7F0 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 (Tg) was estimated about −51.5 °C from a differential scanning calorimetric curve, while chemical decomposition was estimated to start from 385 °C from a thermogravimetry analysis curve. Taking into account the thermal stability in a wide temperature range from −51.5 °C to 385 °C, the SFA-Eu(III) copolymer is expected to act as a potential red component for near-UV excited white LEDs.

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