Photoionic Effect Imposed by Photoresponsive Local Field in a Tellurate Glass with Lanthanide Ions and Ag Nanoparticles.

Abstract

Understanding the photoionic mechanism in optoelectronic materials offers significant potential for various applications in the fields of laser, data/energy storage, signal processing, and ionic batteries. However, the research on such light-matter interaction using photons of sub-bandgap energy is scarce, especially for those transparent materials with photoactive centers that would generate a local field upon photoillumination. This research investigates the photoionic effect in Yb3+/Er3+ doped tellurate glass with Ag nanoparticles (NPs) embedded. It is found that the photogenerated electric dipole of Yb3+/Er3+ ions and local field of Ag NPs could block the Ag+ migration in an external electric field. The blocking phenomenon of Ag NPs is the so-called Coulomb blocking effect (ascribed to its quantum confinement effect), which would be further enhanced by the additional photoinduced localized surface plasmon resonance (LSPR) effect. Interestingly, the photoresponsive electric dipole of lanthanide ions could cause plasmon oscillation of Ag NPs, resulting in a partial release of the blockade of lanthanide ions and enhanced blockade via quantum confinement of Ag NPs. A model device is proposed according to the photoresistive behavior. The research gives another perspective on the photoionic effect via the photoresponsive local field generated by photoactive centers in optofunctional materials.