Charge Carrier Dynamics in Materials with Disordered Structures: A Case Study of Iron Phosphate Glasses

Abstract

Materials with disordered structures have a crucial role in the rapid development of new technologies. Improvement of these materials for particular application, as well as preparation of novel composites is based on a thorough understanding of the basic mechanisms of charge carrier transport. Among various classes of structurally disordered materials, a family of iron phosphate glasses attracts special attention due to their unique combination of structural, electrical and mechanical properties. Generally, iron phosphate glasses are electronically conducting glasses with polaronic conduction mechanism where conduction takes place by electrons hopping from Fe2+ to Fe3+. Consequently, polaron transport directly depends on Fe2+/Fe-tot, ratio and overall Fe2O3 content. However, by altering composition (addition of Cr2O3, MoO3, PbO, Na2O) and preparation conditions, the electrical conductivity of iron phosphate based glasses may vary over many orders of magnitude. This paper gives an overview of our recent studies of electronic and ionic transport in iron phosphate based glasses.