Broadband NIR Garnet Phosphors with Improved Thermal Stability via Energy Transfer

Abstract

Near-infrared (NIR) phosphor-converted lightemitting diodes (pc-LEDs) have attracted more and more attention because of their many potential optical applications. However, high-performance broadband NIR phosphors are still rare. Here, we demonstrated that Cr 3+ -to-Yb 3+ energy transfer (ET) is an effective strategy to boost the properties of NIR luminescence materials in Ca 2 LaZr 2 Ga 2.8 Al 0.2 O 12 : Cr 3+ ,Yb 3+ (CZGG: Cr 3+ , Yb 3+ ). In addition to the enrichment of shortwave NIR emission in 900−1100 nm, the overall thermal stability of CZGG: Cr 3+ , Yb 3+ can be improved by leveraging high-efficiency ET from Cr 3+ to Yb 3+ , ascribed to the fast ET from Cr 3+ to its nearest Yb 3+ as well as the superior thermal stability of Yb 3+ . Additionally, an NIR pc-LED device was packaged via combining CZGG: Cr 3+ , Yb 3+ with a blue LED chip to demonstrate its possible application in compact nonvisible light sources.

Rapid Discovery of Efficient Long-Wavelength Emission Garnet:Cr NIR Phosphors via Multi-Objective Optimization

“…IQE/EQE values of published Cr 3+ -doped garnet NIR materials with different emission wavelengths. (1) Y 3 Al 5 O 12 :Cr, (2) Lu 3 Ga 5 O 12 :Cr, (3) Y 3 Ga 5 O 12 :Cr, (4) Gd 3 Ga 5 O 12 :Cr, (5) Lu 3 Sc 2 Ga 3 O 12 :Cr, (6) Gd 2.4 Lu 0.6 Ga 4 AlO 12 :Cr, (7) Gd 3 Al 2 Ga 3 O 12 :Cr, (8) Y 3 Sc 2 Ga 3 O 12 :Cr, (9) Y 2 CaAl 4 SiO 12 :Cr, (10) CaLu 2 Mg 2 Si 3 O 12 :Cr, (11) Ca 3 Ga 2 Ge 3 O 12 :Cr, (12) Gd 3 Sc 2 Ga 3 O 12 :Cr, (13) Gd 3 Sc 1.5 Al 0.5 Ga 3 O 12 :Cr, (14) Gd 3 Y 0.5 In 0.5 Ga 4 O 12 :Cr, (15) Gd 3 Mg 0.5 Al 1.5 Ga 2.5 Ge 0.5 O 12 :Cr (this work), (16) Ca 3 Sc 2 Si 3 O 12 :Cr, (17) Ca 2 YHf 2 Al 3 O 12 :Cr, (18) Ca 2 LuZr 2 Al 3 O 12 :Cr, (19) Sr 3 Y 2 Ge 3 O 12 :Cr, (20) Ca 3 Y 2 Ge 3 O 12 :Cr, (21) Gd 3 Zn 0.8 Ga 3.4 Ge 0.8 O 12 :Cr, (22) La 3 Sc 2 Ga 3 O 12 :Cr, (23) Ca2LaZr 2 Ga 2.8 Al 0.2 O 12 :Cr, (24) Gd 3 MgScGa 2 SiO 12 :Cr, (25) Ca 4 ZrGe 3 O 12 :Cr …”

Achieving stable photoluminescence by double thiacalix[4]arene-capping: the lanthanide-oxo cluster core matters

“…In additional to moisture stability, the thermal stability of phosphors is another important aspect that is critical for practical applications (the operation temperature of an LED device can reach 150 C). [59][60][61][62] Before analyzing the luminescent stability at high temperature, we rst look at the structural stability of 2 and 4 at elevated temperatures by conducting thermogravimetry analysis (TGA). The TGA curve of 2 do not show signicant weight loss until 327 C, which likely because of the decomposition of ligands (Fig.…”

Blue-light-excitable pure and efficient short-wave infrared luminescenceviaCr3+→ Yb3+energy transfer in a KYbP2O7:Cr3+phosphor

“…37,38 In recent years, several Cr 3+ –Yb 3+ co-doped luminescent materials with broadband emission bands have also emerged, such as Lu 2 CaMg 2 Ge 3 O 12 :Cr 3+ ,Yb 3+ (FWMH: 200 nm, IQE of 84.2%), 16 Sr 9 Cr(PO 4 ) 7 :Yb 3+ (FWMH: 200 nm, IQE of 49.2%), 20 and Ca 2 LaZr 2 Ga 2.8 Al 0.2 O 12 :Cr 3+ ,Yb 3+ (FWMH: 200 nm, IQE of 64.5%). 39 However, such broadband NIR luminescence usually requires that the emission bands of Cr 3+ and Yb 3+ exist simultaneously and their luminescence intensities are almost the same when excited by a blue LED. On the other hand, a handful of research works have also been carried out to obtain the dominant Yb 3+ emission by increasing the Yb 3+ doping concentration.…”