Naslov
Polaronic conductivity in vanadium phosphate glasses and the effect of molybdenum oxide addition

Autori
Razum, Marta ; Pavić, Luka ; Čižmar, Tihana ; Gajović, Andreja ; Pajić, Damir ; Šantić, Ana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
27th Croatian Meeting of Chemists and Chemical Engineers and 5th Symposium Vladimir Prelog : Book of Abstracts / Marković, Dean ; Meštrović, Ernest ; Namjesnik, Danijel ; Tomašić , Vesna - : Hrvatsko kemijsko društvo, 2021, 257-258

Skup
27. hrvatski skup kemičara i kemijskih inženjera (27HSKIKI) ; 5. simpozij Vladimir Prelog

Mjesto i datum
Veli Lošinj, Hrvatska, 05.10.2021. - 08.10.2021

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
polaronic conductivity ; vanadium phosphate glass ; molybdenum

Sažetak
Electronic conduction has been detected in various melt-quenched oxide glasses which contain transition-metal oxides (TMO) such as V2O5, MoO3, WO3, and Fe2O3. These materials are of great scientific interest due to their potential application in many fields such as photonics, electronic circuit elements, gas sensors, etc. The electronic conductivity in these glasses occurs via small polaron hopping between transition metal ions in different oxidation states and strongly depends on the amount of transition metal oxide and a fraction of transition metal ions in different valence states. Among various TMOs which can be incorporated into oxide glasses, vanadium (V) oxide is especially attractive since it participates in the glass network formation and hence can be added in large amounts. Also, it is interesting to investigate how the addition of a second TMO influences the polaronic conductivity in these glasses due to the possible transfer of electrons via different TM ions as well as modification of the structural network which may or may not favor the transport of polarons. In this study, a series of binary xV2O5–(100–x)P2O5 glasses with a wide range of composition from x = 37 to x = 89 mol%, and ternary (60–x)MoO3–xV2O5– 40P2O5 glasses with x = 10-49 mol%, and binary 60MoO3–40P2O5, were prepared by the melt quenching method. The structure and electrical properties of obtained glass samples were investigated by Raman and impedance spectroscopies. The fraction of V4+ ions, V4+/Vtot (binary system), and the sum fraction of V4+ and Mo5+ ions, (V4++Mo5+)/(V+Mo)tot (ternary system) were determined from the temperature dependence of magnetization, measured with SQUID magnetometer, and analyzed using the Curie constant attributed to the isolated paramagnetic centers V4+ and Mo5+. With the increase of V2O5 content bands attributed to the stretching vibrations of V–O, V–O–P, and V– O–V bonds increase in intensity indicating the formation of mixed vanadium-phosphate glass network and clustering of vanadium units at high V2O5 content. The DC conductivity of glasses in the binary system increases nearly linearly with the increase of V2O5 due to an increase in the concentration of vanadium ions reaching the highest conductivity of 1.03 × 10-4 (Ω cm)-1 at 30 °C for glass with 89 mol% V2O5. On the other hand, the systematic replacement of MoO3 with V2O5 in ternary glass series causes a strong increase in conductivity up to 20 mol% of V2O5 followed by a slight increase for higher V2O5 contents, Figure 1. The comparison of glasses from binary and ternary series with approximately the same amount of V2O5 showed higher conductivity values for glasses with MoO3 which indicates that molybdenum actively participates in the polaron conductivity via the transport of electrons between molybdenum and vanadium ions.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

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