Deep-ultraviolet transparent monolithic sol–gel derived silica–REPO₄ (RE = Y, La–Lu except Pm) glass-ceramics: characterization of the crystal structure and ultraviolet absorption edge, and application to narrow-band UVB phosphors

Abstract

Silica–REPO4 glass-ceramics with high deep-ultraviolet transparency (left) and a silica–(Gd,Pr)PO4 phosphor promising as a narrow-band ultraviolet B phosphor (right) have been developed.

Energy Transfer and Quenching in Sol–Gel‐Derived Silica Glass Green Phosphors Doped with Tb3+ and Ce3+ Ions: Distinct Difference between P‐ and Al‐Codoped Glasses

“…Figure shows transmission electron microscope (TEM) images and corresponding energy dispersive X‐ray spectrometry (EDS) mapping images. In the (Tb,Ce)−P‐codoped glasses, nanoparticles with diameters of ≈5 − 10 nm, attributed to (Tb,Ce)PO 4 nanocrystals, [ 41,42,44 ] were seen. The average diameter of the (Tb,Ce)PO 4 nanocrystals was insensitive to z P / z RE .…”

“…Figure shows absorption factor ( f A ), IQE, and external quantum efficiency (EQE) of all samples under excitation 290 nm, calculated from the PL spectra shown in Figure 5 following the procedure reported in previous studies. [ 41–44 ] In the (Tb,Ce)−P‐codoped glasses, f A was ≳0.95 and IQE and EQE increased with an increase in z P / z RE . The best IQE and EQE recorded at z P / z RE = 2 were ≈0.99 and ≈0.95, respectively.…”

“…We have developed cosolvent‐free sol–gel processes to prepare RE − P‐ and RE − Al‐codoped silica glasses without using alcohols, organic solvents, and other nonessential additives. [ 39–46 ] The RE − P‐codoped silica glasses prepared in this way at P to RE molar ratio at ≳1 [ 40 ] are transparent glass‐ceramics containing REPO 4 nanocrystals with diameters of ≈5–10 nm. [ 41–44 ] The concentration of RE ions in REPO 4 crystals is as high as 1.3–1.6 × 10 22 cm −3 , [ 47,48 ] and the small distances between adjacent RE ions (≈0.4 nm) enable rapid energy transfer between them.…”

“…[ 39–46 ] The RE − P‐codoped silica glasses prepared in this way at P to RE molar ratio at ≳1 [ 40 ] are transparent glass‐ceramics containing REPO 4 nanocrystals with diameters of ≈5–10 nm. [ 41–44 ] The concentration of RE ions in REPO 4 crystals is as high as 1.3–1.6 × 10 22 cm −3 , [ 47,48 ] and the small distances between adjacent RE ions (≈0.4 nm) enable rapid energy transfer between them. In silica−(Tb,Ce)PO 4 glass‐ceramics, excitation into the 4f–5d transition of Ce 3+ ions induces bright green PL from the 4f–4f transitions of Tb 3+ ions.…”

Temperature dependence of narrow-band UVB photoluminescence of silica–(Gd,Pr)PO4 transparent glass-ceramic phosphors

“…with the 6 P 7/2 → 8 S 7/2 4f-4f transition. In several inorganic rare-earth (RE) compounds doped with both Gd 3+ and Pr 3+ ions, including REPO 4 [4][5][6][7][8], BaRE 4 Si 5 O 17 [9], RE 3 Al 5 O 12 [10], REBO 3 [11,12], Ca 3 RE 3 (BO 3 ) 5 [12], REF 3 [13], and REAlO 3 [14,15], photoexcitation into the 4f-5d transition of Pr 3+ ions results in an efficient photosensitisation of the UVB PL band of Gd 3+ ions.…”