Structural and thermochemical study of Na2O–ZnO–P2O5 glasses

Structural and emission properties of Eu3+‐doped alkaline earth zinc‐phosphate glasses for white LED applications

“…Among various glass‐forming oxides, phosphate glasses have been extensively investigated due to their unique characteristics like low melting and softening temperature, transparency in the wide spectral region (UV to IR), and high mechanical and thermal stability . Phosphate glasses have tetrahedral structure described by Q n ( n =0‐3) terminology, where n is the number of bridging oxygen per tetrahedron.…”

“…The absorption peaks centered at band 748 and 925 cm −1 are attributed to the symmetric stretching, ʋ s (PO 2 ), and antisymmetric stretching, ʋ as (PO 2 ), of the P–O–P linkages of the bridging oxygen atoms bonded to the phosphorous, respectively . The simultaneous occurrence of bands present at 748 and 925 cm −1 indicate the presence of pyrophosphate structure (P 2 O 7 ) 4− . The band in the region 800‐1400 cm −1 is broad, and this band consists of several peaks.…”

“…However, the hygroscopic nature and poor chemical durability of the phosphate glasses are a major hindrance in their practical applicability for devices. The incorporation of ZnO makes phosphate as moisture resistant due to the formation of P‐O‐Zn bonds and plays the dual role: either as a glass former in fourfold coordination or as a glass modifier in sixfold coordination . ZnO offers special properties that have drawn the significant interest of researchers like low cost, low toxicity, non‐hygroscopic, direct band gap, and intrinsic emitting property and large exciton binding energy .…”

Encapsulation of nitride phosphors into sintered phosphate glass by pressureless firing and hot isostatic pressing

“…The band with the peaks at 890‐928 cm −1 (see arrow marks) belongs to the combined effects of asymmetric vibrations, ν as (P–O–P) of bridging oxygen atoms in phosphate chains, and Zn–O stretching vibration characteristic for [ZnO 6 ] coordination. The shift of absorption peak from 890 cm −1 toward 928 cm −1 with increasing heating temperature may be explained in terms of the replacement of 2Na + by Zn 2+ . The bands with the peaks at 1090 and 1258 cm −1 are ascribed to the asymmetric vibrations, ν as (PO 2 ), and symmetrical stretching vibration, ν s (PO 2 ), of the non‐bridging oxygen atoms in the phosphate chains, respectively.…”

“…Such glass has to possess low T g enough to prevent from thermal degradation of phosphors during processing of the glass. Promising candidates are the phosphate glasses, such as (50‐ x )Na 2 O– x ZnO–50P 2 O 5 whose T g is lowered down to 283°C with Na 2 O content up to 45 mol% . Furthermore, the chemical durability of 10Na 2 O–(55‐ x )ZnO– x B 2 O 3 –35P 2 O 5 glass may be enhanced with B 2 O 3 content, regardless of the increase in T g .…”