Transport properties of silver selenomolybdate glassy ionic conductors

Abstract

Transport properties of silver selenomolybdate glassy ionic conductors have been reported for wide composition and temperature ranges. It has been observed that the transport properties of these glasses depend strongly on the modifier content as well as on the glass formers ratio. A direct correlation between the ion transport and the modification of the glass structure has been predicted. Transport properties of these glasses are also strongly influenced by the existence of dual character of SeO 2 as a glass former and a glass modifier. Structural models for different compositions have also been proposed. V

Dynamics of silver ions in AgI doped Ag2O–SeO2–MoO3 mixed former glasses

“…A minimum in the conductivity is observed for y = 0.5. It has been observed that in undoped 0.3Ag 2 O-0.7(ySeO 2 -(1 À y) MoO 3 ) glasses the conductivity increases with the increase of the SeO 2 content up to y = 0.7 and then the conductivity decreases slightly for y = 0.8 20. From Fig.2(a) and (b) it is clearly seen that the value of the ionic conductivity is less affected by the network structure and is mainly influenced by the AgI content, i.e., the mixed network former effect in these glasses is overridden by the silver ion conductivity of AgI.…”

Mixed Glass Former Effect in Ag2O–SeO2–TeO2 Glasses: Dependence on Characteristic Displacement of Mobile Ions and Relative Population of Bond Vibrations

“…However, for higher mixed former ratio, the SeO 3 2− ions have a tendency to bond with Ag + ions and form isolated Ag 2 SeO 3 crystalline structure, which in turn reduces the availability of the effective nonbridging hopping site. 16 It has been observed in various selenium− borate 38 and selenium−molybdate 16 glasses that, when sufficient Ag + ions are present in the glass structure, a part of SeO 2 participates in the formation of silver−selenite immobile structure. In a few selenite glasses containing Cu 2+ ions, the formation of a composite copper−selenite structure has been observed.…”

“…Initially, the vibration of SeO 3 2– ions is predominant, as the polarizability as well as the availability of the number of nonbridging hopping sites facilitates faster ion conduction. However, for higher mixed former ratio, the SeO 3 2– ions have a tendency to bond with Ag + ions and form isolated Ag 2 SeO 3 crystalline structure, which in turn reduces the availability of the effective nonbridging hopping site . It has been observed in various selenium–borate and selenium–molybdate glasses that, when sufficient Ag + ions are present in the glass structure, a part of SeO 2 participates in the formation of silver–selenite immobile structure.…”

“…14,15 It is clear that a complex scenario is associated with the mixed glass-network former effect. It has been observed in SeO 2 −B 2 O 3 and SeO 2 −MoO 3 mixed former glasses that Se−O clusters depolymerize the borate and molybdate network and create nonbridging oxygen, 16,17 and the availability of more polar clusters facilitates ion migration in these glasses. 17 In TeO 2 −P 2 O 5 glasses some heteroatomic P− O−Te linkages are observed at a lower concentration of tellurium.…”

“…On the other hand, the conductivity for several mixed former glasses, such as Bi 2 O 3 –B 2 O 3 and TeO 2 –B 2 O 3 glasses, passes through a minimum value, instead of a maximum value, with the change in the mixed former ratio. , It is clear that a complex scenario is associated with the mixed glass-network former effect. It has been observed in SeO 2 –B 2 O 3 and SeO 2 –MoO 3 mixed former glasses that Se–O clusters depolymerize the borate and molybdate network and create nonbridging oxygen, , and the availability of more polar clusters facilitates ion migration in these glasses . In TeO 2 –P 2 O 5 glasses some heteroatomic P–O–Te linkages are observed at a lower concentration of tellurium .…”