Luminescent properties of Sr2MgSi2O7:Eu~(2+) as blue phosphor for NUV light-emitting diodes

摘要

Akermanite phosphor Sr2MgSi2O7:Eu~(2+) was synthesized by solid-state reaction under a H2-N2 atmosphere, and its photo-physical behaviors were systematically characterized by photoluminescence excitation and emission spectra, concentration quenching, and thermal quenching process. This phosphor is efficiently excited in the wavelength range of 300-420 nm, which matches to a near UV-emitting InGaN chip, and emits strong and wide band blue light peaking at 470 nm. The relationship between emission peak wavelength and Eu~(2+) occupied sites was illuminated through Van Uitert's equation. The concentration quenching mechanism was verified to be a dipole-dipole interaction and the critical energy-transfer distance was confirmed as around 13 A through both calculated crystal structure method and experimental spectral method. The activation energy for thermal quenching was calculated to be 0.4044 eV. Phosphor-converted LED was fabricated with Sr2MgSi2O7:0.06Eu~(2+) and 395 nm-emitting InGaN chip and exhibited strong wide band blue emission. These results indicate that Sr2MgSi2O7:Eu~(2+) is a promising candidate as a blue component for near UV-based multi-phosphor-converted white LEDs.