RELAXATION PHOTOCURRENT AT THE ELECTRONIC EMISSION FROM LITHIUM INTO THE SURFACE PASSIVATING FILM

The kinetics of the photoeffect in the system lithium/surface passivat ing film/non-aqueous electrolyte solution was studied using the laser pulse method. A theoretical analysis was performed of electron photoem ission kinetics from the metal into an ion-conducting passivating film which, in particular, may have traps. Comparison of experimental and calculated curves showed that the decreasing part of the oscillograms (current-time curves) could be described by the equation of non-statio nary diffusion for concentration of photoemitted electrons, This macro scopic diffusional motion in disordered solids can arise from microsco pic random trapping and detrapping events and the corresponding diffus ion coefficients must be considered as effective ones. The values of e ffective diffusion coefficients of electrons in passivating films form ed at the lithium surface in a 1 M solution of LiClO4, in a mixture of propylene carbonate with dimethoxyethane were determined and were equ al to ca. 10(-14) m(2) s(-1) at 298 K.