Analysis of Root Mean Square Roughness of Microcrystalline Silicon Thin Films Using Scanning Probe Image Processor software

Abstract

Electron transport and recombination has been investigated in dye-sensitized electrochemical solar cells at varying Ti02 film thickness using experimental electrochemical potential technique. Photocurrent transients resulting from small-amplitude square wave modulation of the incident light were analyzed, and the effect of illumination intensity and film thickness studied. Photovoltage decay measurements were studied on solar cells when switched from short-circuit and under illumination to open circuit and dark at varying illumination intensity for different film thickness. The analysis was done for varying film thickness at constant illumination intensity and varying illumination intensity at constant film thickness. The varying film thicknesses in this study were 3.0 um, 6.0 urn, 12.8 urn, 23.5 urn and 25.3 urn while illumination intensities were 0.5, 1.2, 2.4, 5.1, 9.0 and 15.6 rnwcrn", The voltage decay measured (known as open circuit voltage, Vsc) was seen to first rise to a maximum value then followed by decay. The maximum Vsc (Vsc, max) increased with film thickness at constant prior illumination. On the other hand, Vsc, max was found to depend on the prior illumination and exhibited logarithmic increase with light intensity. The time (tmax) to attain Vsc, max varies exponentially with light intensity and closely matches the electron transport time measured by photocurrent decay measurements.