Safranine T dye based photo electrochemical solar cell: Effect of electrodes on device mechanism

Abstract

We made two photovoltaic devices using blend of Safranine T dye in a thin film of polyvinyl alcohol mixed with solid electrolyte made by PEO and LiClO4, placed between two electrodes, resulting photo electrochemical cell (PEC) structure. One of the cells made of two ITO coated glass plates as electrodes and the other with ITO and Silver. The current voltage relation of the cells has been measured in the dark. Detail analysis of the dark I-V curve shows two distinct regions below and above certain voltage for the second cell unlike to first cell, which has only one region. I- V curve for the cells indicates trap charge limited (TCL) conduction through exponentially distributed traps. Characteristic trap energy (Et) has been calculated for both the cells. Use of dissimilar electrodes increases efficiency up to one order in magnitude than the other. From photovoltaic current growth nature we discussed the charge transport process through these materials using concept of dispersive transport model.