High-brightness Eu3+-doped Ca9Gd(PO4)7 red phosphor for NUV light-emitting diodes application

Orange‐Red‐emitting Ca9Gd(PO4)7:Eu3+ Phosphors: Judd‐Ofelt Analysis and Investigation on the Thermal Stability, Quantum Efficiency for WLED

“…Compared with conventional lightings such as incandescent, halogen, xenon, fluorescent lamps, white light emitting diodes (WLED) have the tremendous advantages of compact size, high brightness, lower energy consumption, high reliability, long life time and environment‐friendliness [1–6] . A typical WLED was simply fabricated by combining a 460 nm blue InGaN chip with a cerium(III)‐doped yttrium aluminum garnet yellow phosphor, Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) [7–11] . However, due to the shortage of red spectral component, this type of LED has a low‐quality color rendering index (R a =70–80) and a high correlated color temperature (CCT=4000–7500 K) [7,12–15] .…”

“…A typical WLED was simply fabricated by combining a 460 nm blue InGaN chip with a cerium(III)‐doped yttrium aluminum garnet yellow phosphor, Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) [7–11] . However, due to the shortage of red spectral component, this type of LED has a low‐quality color rendering index (R a =70–80) and a high correlated color temperature (CCT=4000–7500 K) [7,12–15] . Thus, using yellow‐emitting phosphors with a better red contribution to coat is prevalently used for obtaining a high‐R a white light and an efficient CCT.…”

“…12 It is reported that WLED could also be achieved by coating white‐emitting phosphors on a NUV‐LED, [16] i. e., based on Y 2 O 2 S:Eu 3+[17] and NUV InGaN chip 7 or UV LED and RGB (red/blue/green) phosphors. Unfortunately, the biggest drawbacks of Y 2 O 2 S:Eu 3+ phosphor are chemically instable and easy to be aged under UV irradiation [7,18–20] . Hence, the commercial Y 2 O 2 S:Eu 3+ phosphor could not exhibit a good performance under excitation of NUV or blue light irradiation, limiting its application in WLED lighting [21] .…”

“…Phosphates of type A 9 B(PO 4 ) 7 , where A is a bivalent ion, (i.e: Ca, Sr) and B is a trivalent ion (i.e: Sc, La, Y, Gd or Bi), have recently attracted a great of attention due to their excellent conversion efficiency [3,7,22] . These phosphate compounds possess many superior advantages such as high chemical stability, high band‐gap energy and ease to synthesize by a simple and low‐cost method [23] .…”

“…These phosphate compounds possess many superior advantages such as high chemical stability, high band‐gap energy and ease to synthesize by a simple and low‐cost method [23] . Among them, Ca 9 Gd(PO 4 ) 7 is one of the most common A 9 B(PO 4 ) 7 types [7,22,23] . Guo et al.…”