Dual Liquid Junction Photoelectrochemistry: Part I. Dual-Cuvette and Dual-Thin-Film Cells for Screening and Quantification of Back-Contact Properties.

We explore methods for utilizing electrochemical redox contacts both at the front and back of illuminated semiconductors. A dual cuvette cell utilizes a cuvette/gasket/semiconductor/gasket/cuvette sandwich with rapid stirring and the capability for fourelectrode measurements. Results from the dual-cuvette cell include current density--potential (J-E) scans with a cobaltocene^+/0 back contact to n--Si(111) and a ferrocene^+/0 front contact facing the illumination source, and a logarithmic plot of short-circuit current density vs open-circuit photovoltage for several illumination intensities to quantify the diode ideality factor for this cell. An ITO/liquid/semiconductor/liquid/ITO sandwich in a two-electrode configuration comprises a thin-layer cell. Thin-layer cell results include J--E scans as well as electrochemical impedance/Mott-Schottky analysis of flatband potentials. Results on n--Si(111) electrodes with two liquid junction contacts resemble results from traditional photoelectrochemical cells with a rectifying liquidjunction front contact and a rear metal contact. [ABSTRACT FROM AUTHOR]