荧光素基 PGMA 的合成及其发光性能.

Fluorescein（ Flu） was introduced into poly(glycidyl methacrylate) (PGMA) chains by atomic transfer radical polymerization (ATRP) and fluorescein-based PGMA (Flu-PGMA) was prepared by using traditional fluorescein with aggregation induced quenching (ACQ) effect as initiator and glycidyl methacrylate (GMA) as monomer. The thermal and fluorescence properties of Flu-PGMA were characterized by differential scanning calorimetric, thermogravimetric analysis, steady-state and transient-state fluorescence spectrometers, and the device properties of white light-emitting diodes (LEDs) were investigated by PR655 spectrometer. The results showed that PGMA could overcome the ACQ effect of fluorescein, and the number-average molecular weight was 2.64×10 4and polydispersity of Flu-PGMA was 1.5. The glass transition temperature and thermal decomposition temperature of Flu-PGMA could reach up to 79.8 °C and 280 °C, and its excellent thermal properties satisfy the needs of a phosphor. In addition, the Flu-PGMA presented excellent visible light transmittance of 64%–68% in a wavelength range of 400–800 nm. The solid-state fluorescence quantum yield of Flu-PGMA could reach up to 14.27%. The photoluminescence spectra exhibited excitation-independent characteristics and the strongest emission peak was located at 550 nm, which belongs to yellow emission. The average fluorescence decay lifetime fitted by biexponential function was 4.55 ns. When it was applied as a single-phase solid phosphor, a white LED with a color rendering index of 84 was fabricated under the excitation of 460 nm InGaN blue chip at a driving voltage of 2.7 V, which is higher than that of fluorescein-based LEDs reported at present. The correlated color temperature was 9 455 K and the color coordinates were located at (0.289, 0.282), which belongs to the white gamut. [ABSTRACT FROM AUTHOR]