A color tunable and white light emitting Ca2Si5N8:Ce3+, Eu2+ phosphor via efficient energy transfer for near-UV white LEDs. Issue 19 (4th May 2018)

• Record Type: Journal Article
• Authors: Li, Chao; Zheng, Hongwei; Wei, Hengwei; Qiu, Shijie; Xu, Ling; Wang, Xiaoming; Jiao, Huan
• Is Part Of: Dalton transactions. Volume 47:Issue 19(2018)
• Page Start: 6860
• Page End: 6867
• Publication Date: 2018-05-04
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt01430b
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Achieving tunable color and white light emission in a single phase phosphor is a challenging issue. Abstract : Achieving tunable color and white light emission in a single phase phosphor is a challenging issue. Here, a series of Ce 3+ –Eu 2+ co-doped Ca2 Si5 N8 phosphors were successfully synthesized by a high temperature solid state method. Luminescence properties, energy transfer (ET) and thermal quenching of the as-synthesized samples were investigated in detail. The emission color of as-prepared Ca1.94 Na0.03 Si5 N8 :0.03Ce 3+, y Eu 2+ (0.0000 ≤ y ≤ 0.0035) could be tuned from blue to white light and eventually to orange via ET by changing the Ce 3+ /Eu 2+ ratio. ET efficiency from Ce 3+ to Eu 2+ could reach up to 68.0% and the ET mechanism was demonstrated to be a non-radiative dipole–dipole interaction. More importantly, when y = 0.0012, approximate standard white light was generated with CIE coordinates of (0.335, 0.341). A photoluminescence (PL) mechanism was proposed to understand PL properties and thermal properties of the as-prepared phosphors. Additionally, the achieved white light phosphor Ca1.9388 Na0.03 Si5 N8 :0.03Ce 3+, 0.0012Eu 2+ had good thermal stability, exhibiting about 75% at 150 °C and 64% at 200 °C of the emission intensity at 25 °C, respectively. The chromaticity shifts of Ca1.9388 Na0.03 Si5 N8 :0.03Ce 3+, 0.0012Eu 2+ were 0.0032 at 150 °C and 0.0152 at 200 °C, respectively, which were only 27% and 42% of the commercial white-emitting phosphor mixture at the corresponding temperature. Furthermore, a proof-of-concept white LED was fabricated by combining the single component phosphor Ca1.9388 Na0.03 Si5 N8 :0.03Ce 3+, 0.0012Eu 2+ with a near UV LED chip. All results demonstrate the promising application of the Ca2 Si5 N8 :Ce 3+, Eu 2+ single phosphor for near-UV white LEDs.