Luminescence color tuning and energy transfer properties in (Sr,Ba)₂LaGaO₅:Bi³⁺,Eu³⁺solid solution phosphors: realization of single-phased white emission for WLEDs

Abstract

Controllable emission tuning from bluish-green to red was achieved by Ba2+/Sr2+ substitution and Bi3+ → Eu3+ energy transfer.

Enhanced Cyan Emission and Optical Tuning of Ca3Ga4O9:Bi3+ for High‐Quality Full‐Spectrum White Light‐Emitting Diodes

“…As presented in Figure a, the emission spectra of CGO:0.02Bi 3+ , 0.07Zn 2+ , n Eu 3+ ( n = 0–0.15) phosphors exhibit both the broad emission band of Bi 3+ and the sharp emission peaks of Eu 3+ ( 5 D 0 → 7 F J , J = 0, 1, 2, 3, and 4). [ 13 ] As Eu 3+ concentration increases, the emission intensity of Bi 3+ monotonically decreases while that of Eu 3+ gradually increases, demonstrating the existence of energy transfer from Bi 3+ to Eu 3+ in CGO:0.02Bi 3+ , 0.07Zn 2+ , n Eu 3+ ( n = 0–0.15) phosphors. The luminescence photographs of these phosphors under 365 nm UV lamp excitation are given in Figure 6b, Supporting Information, which shows the emission tuning from cyan to orange across the white light region.…”

“…[ 10 ] As another activator species, Bi 3+ stands out with broad emission band and nearly no reabsorption problem encountered by rare earth ions because it has characteristic excitation in n‐UV rather than in the visible region, thereby avoiding the visible light reabsorption. [ 11 ] There have been several Bi 3+ doped cyan‐emitting phosphors such as LiGd 5 P 2 O 13 :Bi 3+ , [ 12 ] SrBaLaGaO 5 :Bi 3+ , [ 13 ] and Ba 1.5 Sr 1.5 Sc 4 O 9 :Bi 3+ . [ 14 ] But the excitation energy of LiGd 5 P 2 O 13 :Bi 3+ (λ ex = 290 nm) is too high to match well with the n‐UV chips typically generating light beyond 360 nm.…”

Recent Advances in Bismuth Ion‐Doped Phosphor Materials: Structure Design, Tunable Photoluminescence Properties, and Application in White LEDs

“…Different emission tuning phenomenon occurs in Bi 3+ ‐doped Sr 2− x Ba x LaGaO 5 solid solution phosphors. [ 40 ] As shown in Figure 9d–e, the Bi 3+ emission have a red shift from blue to green when the C h sites (Sr 2+ ) are replaced by the larger Ba 2+ . Here, the crystal field strength is affected by both bond length and lattice distortion.…”

“…Reproduced with permission. [ 40 ] Copyright 2019, Royal Society of Chemistry.…”

“…The similar red‐shift in emission peaks was reported by our group. [ 30,40 ] Figure 13e presents the PL spectra of Sr 3 Sc 4 O 9 :Bi 3+ under different excitation wavelengths ranging from 300 to 342 nm. Because the substitution of Bi 3+ into the Sr 3 Sc 4 O 9 crystal lattice happens at Sr 2+ and Sc 3+ sites simultaneously, the emission peak has a remarkable red‐shift with increasing the excitation wavelength.…”