Local structure and luminescent properties of Cs2KGaF6:Mn4+ phosphor for backlight white LEDs

作者：Li, Jing; Wang, Yuanjing^*; Zhe, Haifeng; Zhou, Yayun; Zhou, Qiang; Wang, Zhengliang^*

来源：Journal of Alloys and Compounds, 2021, 881: 160624.

DOI：10.1016/j.jallcom.2021.160624

• Red phosphor
• Mn4+-doped
• White light-emitting diodes
• Display
• Luminescence

Narrow-band red-emitting phosphors are worth investigating and developing to enhance their luminescence efficiency for white light-emitting diodes (WLEDs) and broaden the color gamut of backlight displays. Herein, a novel red-emitting fluoride phosphor Cs2KGaF6:Mn4+ (CKGFM) was synthesized, which presents sharp red emission bands, short fluorescence lifetime (tau = 3.81 ms) and high external quantum efficiency (EQE = 43%). To better understand Mn4+ incorporation in CKGFM, density functional theory (DFT) energetic calculations were performed to compare the charge compensation probabilities of an Mn4+ substituted at a Ga3+ or K+ site. The temperature-dependent luminescence trend shows that the CKGFM phosphor has good thermal stability in the temperature range of 15-120 degrees C, indicating its potential in backlight LEDs. The as-prepared CKGFM phosphor was used to fabricate one white light-emitting diode (WLED) with beta-SiAlON:Eu2+ green phosphor and blue InGaN LED chip, which shows a high luminous efficiency of 106.30 lm.W-1 and a National Television Standards Committee (NTSC) value of 114.6%. The present study provides detailed insights into the local structure of Mn4+ substituted in fluoride red-emitting phosphors and helps to realize better Mn4+ emission for WLEDs.

• 单位
  云南大学