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A new phenomenon of a reversible photoinduced coloration caused by light irradiation is discovered and investigated in superionic RbAg 4 I 5 crystals. The reversible photoinduced absorption is found to be a result of irradiation by light with wavelengths in the region from 420 nm to 450 nm. The proposed mechanism of the discovered effect is associated with ambipolar diffusion of screened by mobile ions optically excited electronic carriers. The processes of color centers creation in superionic crystals RbAg 4 I 5 due to additive coloring in iodine vapours, ionic implantation and γ-ray irradiation are considered.

The phenomena of Schottky barrier creation in RbAg4I5 are studied. Luminescence with high spatial resolution is used as a tool for investigation of the process on the blocking electrode-solid electrolyte boundary. The profile of the distribution of electronic centers near the contact region is measured. The presence of electrons and ions in the depletion region at the interface between the RbAg4I5 and the graphite electrode is established and interpreted within the framework of the modified Schottky model. The kinetics of the creation of Schottky barriers is measured and described by taking into account the presence of self-trapped electrons and mobile silver ions in RbAg4I5. It is shown that the small value of the self-trapped electron diffusion coefficient (Dst ≃ 1 × 10−8cm2/sec) limit the kinetics of the process of creation of Schottky barriers.

We have observed a new phenomena of photoinduced transformation of Raman scattering and photoluminescence spectra in RbAg 4 I 5 superionic crystal. A reversible change of the fine structure in Raman spectra at low temperature and reversible change of the concentration of luninescence centers due to irradiation of sample have been studied. Both of these processes are due to the change of local concentration of mobile silver ions in irradiated region of RbAg 4 I 5. The mechanism of interaction between nonequilibrium electrons and silver disordered ionic sublattice has been proposed. The excess concentration of electrons gives rise to diffusion flow of electrons and ions from irradiated region.

The effect has been studied of additive coloring on the magnitude of ion conductivity of RbAg4I5 crystals. It has been found that slight changes of silver stoichiometry of 10−3 at.% can lead to considerable variations of the ionic conductivity Δ[sgrave]i/[sgrave]i ≃ 0.1. The dependence has been observed of the magnitude of ion conductivity on the ratio between the integral intensities of the main bands in the photoluminescence spectrum of the γ-phase of RbAg4I5 which associated with the luminescence centres containing vacancies and interstitials of silver cations.

Onset of electric current has been detected on illuminating the near–contact regions of RbAg4I5 crystals. The spectral and temperature characteristics of this current have been studied. A method is proposed for studying the spectrum of electronic states in the α-phase of the RbAg4I5 crystal. The dependence of the magnitude of the current and its spectral characteristics on the particular region of the RbAg4I5 crystal which is exposed to the light was used for the analysis of the variations in the distribution of defects along the length of the sample and the processes which occur near the electrode-(solid electrolyte) junctions.