Red-emitting Eu3+-activated TiO2phosphors with excellent color purity of 99.9% have been successfully synthesized by a facile sol-gel method. PLE spectrum demonstrates that the obtained products have absorption bands ranging from 370 to 540 nm, with the highest band peaking at 464 nm. Under the blue excitation of 464 nm, the characteristic emissions of Eu3+ ions corresponding to the 5D0 → 7FJ transitions are observed, with the dominant emission peak at 614 nm. The optimal annealing temperature and dopant concentration are 5 h at 500 °C and 1.3 mol%, respectively. The PL quenching mechanism is attributed to the dipole-quadrupole interaction. The Judd-Ofelt analysis is carried out to explore the local structure environment around the Eu3+ ions. It is found that the highest asymmetry of the local environment surrounding Eu3+ ions and the strongest covalence Eu-O bond is attained at the annealing temperature of 500 °C and the activation energy is determined to be 0.385 eV. The fluorescence lifetime of the 614 nm emission was found to be 0.44 ms. These results indicate that the Eu3+-doped TiO2 phosphor may be a promising red-emitting phosphor for white light-emitting diodes.
Tạp chí khoa học Trường Đại học Cần Thơ
Lầu 4, Nhà Điều Hành, Khu II, đường 3/2, P. Xuân Khánh, Q. Ninh Kiều, TP. Cần Thơ
Điện thoại: (0292) 3 872 157; Email: tapchidhct@ctu.edu.vn
Chương trình chạy tốt nhất trên trình duyệt IE 9+ & FF 16+, độ phân giải màn hình 1024x768 trở lên