Enhanced red emission and improved thermal quenching of CaAlSiN₃:Eu²⁺ phosphors via boron doping

Abstract

The development of high‐performance phosphors is required for phosphor‐converted white light‐emitting diodes. However, most approaches are unable to achieve optimum emission intensity and thermal quenching simultaneously. Here, a series of CaAlSiN3:Eu2+ (CASN:Eu2+) red‐emitting phosphors doped with B were synthesized using field‐assisted sintering technology. Compared with CASN:Eu2+, the B‐doped phosphor exhibited high external quantum efficiency (EQE) and good thermal quenching performance. With boron doping, the EQE of CaAlSiN3:Eu2+ shows an obvious growth, increasing from 48.83% to 70.68%. Meanwhile, thermal quenching performance has also been greatly improved, which is strongly associated with the band structure of Eu2+ and the crystal structure of CASN. The location of B in the crystal lattice was studied and the mechanism of improving thermal quenching via B doping was discussed in detail. Finally, a white LED fabricated by the combination of a GaN blue chip (450 nm) with the as‐synthesized red phosphors and Y3(Al, Ga)5O12:Ce3+ green phosphors (531 nm), shows a high color rendering index (Ra =91.6). This study offers a novel method to improve luminescence properties of CASN:Eu2+ red‐emitting phosphors, which may broaden their application in solid‐state lighting devices.

Strong f–f excitation in hafnium germanate: Near‐UV LED and cathode beam–pumped red phosphor with thermal robustness

“…White light-emitting diodes (WLEDs) have become a new generation of solid-state lighting sources due to their advantages of energy saving, environmental protection, and long service life. [1][2][3][4][5][6][7][8] The first generation of WLEDs uses a combination of blue LED chips and yellow phosphors, which has the advantages of high brightness and low cost. However, due to the absence of red light in the emission spectrum, this type of WLEDs exhibits poor color rendering and high color temperature.…”

“…White light‐emitting diodes (WLEDs) have become a new generation of solid‐state lighting sources due to their advantages of energy saving, environmental protection, and long service life 1–8 . The first generation of WLEDs uses a combination of blue LED chips and yellow phosphors, which has the advantages of high brightness and low cost.…”