Visible and Near-Infrared Emission in Ba₃Sc₄O₉:Bi Phosphor: An Investigation on Bismuth Valence Modification

Abstract

Bismuth (Bi)-activated luminescence materials have attracted much attention for their tunable broad emissions ranging from a visible to near-infrared (NIR) region. However, it remains a challenge to regulate the Bi valence state and achieve NIR emission via a facile way. Here, we report the design and preparation of Ba3Sc4O9:Bi phosphors, which emit visible and NIR emissions simultaneously even prepared in the air condition. The self-reduction mechanism of Bi3+ species in Ba3Sc4O9 with a rigid crystal structure is illustrated based on the charge compensation model, and the coexistence of different Bi-active centers, Bi3+ for visible emission, while Bi+ and Bi0 for NIR emission, is confirmed by the spectroscopic data and X-ray photoelectron spectroscopy (XPS) analysis. The enhanced NIR emission was further achieved through controlled reducing treatment and the related mechanism has also been clarified. This work paves a new way to control bismuth valence and tune the emission of Bi-based luminescence materials for emerging photonics applications.

Realization of an Optical Thermometer via Structural Confinement and Energy Transfer

“…All the excitation spectra included a weak band in the range of 227–275 nm and a strong signal between 275 and 392 nm (Figure a). The former is ascribed to the typical transition of 1 S 0 → 1 P 1 , and the latter is related to the 1 S 0 → 3 P 1 transition of Bi 3+ ions. − When the excitation wavelength was monitored at 324 nm, the broad symmetrical PL band in the range of 350–600 nm can be clearly seen, and it originated from the typical transition of Bi 3+ : 3 P 1 → 1 S 0 (Figure b). There are substantial changes in the emission intensity and peak position with varying x content.…”

Metal To Metal Charge Transfer Induced Efficient Yellow/Far‐Red Luminescence in Na2Ca3(Nb, Ta)2O9:Bi3+ toward the Applications of White‐LEDs and Plant Growth Light

“…Bi ion can exist in multiple valence states in solid compounds, which has great influence on the luminescent properties. [23] Therefore, the X-ray photoelectron spectroscopy (XPS) spectra of 1.0 mol% Bi 3+ -doped Na 2 Ca 3 (Nb, Ta) 2 O 9 and α-Bi 2 O 3 as a reference were measured and shown in Figure 2b. They both peak at ≈159.3 and 164.6 eV, which are assigned to the 4 f 7/2 and 4 f 5/2 structure of Bi 3+ , respectively, implying the state of trivalence.…”

Persistent phosphors for luminous paints: A review

“…Li et al have explored NIR emission in Ba 3 Sc 4 O 9 :Bi phosphor with multiple crystallographic sites feasible for emerging photonic applications. [ 100 ] The self‐reduction mechanism of bismuth ion (Bi 3+ ) in Ba 3 Sc 4 O 9 host possessing a rigid crystal structure is exemplified employing the charge compensation model. The self‐reduction mechanism of Bi 3+ was analysed by the charge compensation model and the rigid crystal structure of the host material.…”

“…Li et al have explored NIR emission in Ba 3 Sc 4 O 9 :Bi phosphor with multiple crystallographic sites feasible for emerging photonic applications. [100] The selfreduction mechanism of bismuth ion (Bi 3+ ) in Ba a multi-spectral excited NIR PP that gets re-charged either by red LED or laser diode array and lasers in the NIR region. [102] 10 | LIMITATIONS AND LATEST TRENDS…”