Study of the interface changes during operation of nCdTe-electrolyte solar cells

Abstract

Previous work has shown that while nCdTe‐electrolyte solar cells are low cost and efficient, their photocurrent decays after a few hours of operation. We ave systematically analyzed the changes that take place at the interface. Auger spectroscopy measurements have shown out‐diffusion of Cd²⁺ and the formation of a Te layer at the surface. Electroreflectance (ER) and electroluminescence measurements have further shown that this process results in the formation of a p‐type region. The evolution of the ER spectra as the p‐type region develops was followed and fully analyzed. This technique offers the advantage of easy control and optimization of the p‐n junction growth parameter. The influence of the Te layer on the cell performance was determined from spectral response measurements.