Effect of illumination intensity and temperature on open circuit voltage in organic solar cells

The effect of illumination intensity and temperature on open circuit voltage (V-oc) in organic photovoltaic devices has been investigated. V-oc is observed to saturate at high illumination intensities. The illuminated J-V characteristics at different intensities intersect the dark characteristic at a single point. This intersection point is shown to be equal to the built-in voltage (V-bi) in the sample. A reduction in temperature shows increment in saturated V-oc. This increment in saturated V-oc is attributed to the variation of V-bi with temperature. A model has been presented that explains the observed behavior of V-bi at different temperatures.