A thermally stable narrow-band green phosphor Na2MgAl10O17: Eu2+, Mn2+ for NUV LED application

Abstract

Thermally stable narrow-band green phosphor is important for phosphor-converted light emitting diodes (pc-LEDs). Herein, an efficient and stable Na2MgAl10O17: Eu2+, Mn2+ green phosphor is obtained using Eu2+-Mn2+ energy transfer strategy. The Mn2+ activator could be effectively sensitized by the addition of Eu2+ with significant UV absorption enhancement, then generates a bright green emission with peak at 515 nm and FWHM of 40 nm. The internal and external quantum efficiencies of optimal phosphor Na2MgAl10O17: 0.15Eu2+, 0.50Mn2+ are measured as 69.5 and 30.8 %, respectively. It is found that Na2MgAl10O17: Eu2+, Mn2+ phosphor shows good chemical and thermal stability, i.e. maintains no quenching after H2O/HCl soaking and keeps 90 % of RT intensity at 200 °C. By using Na2MgAl10O17: Eu2+, Mn2+ as converted phosphor, single-chromatic and white pc-LEDs were fabricated, which simultaneously achieve green and white emission with high brightness. Our results show that this Na2MgAl10O17: Eu2+, Mn2+ is a potential candidate as a thermally stable green phosphor for white LEDs.