Minority carrier lifetime, measurement of solar cell

The experimental technique for determining the minority carrier lifetime within the base region of p-n junction solar cells is presented in this paper. The value of minority carrier lifetime is of tremendous use in estimating the performance of solar cell. The procedure is to illuminate the solar cell with a flash of white light from light source for say, microseconds and then to monitor the decay nature of open circuit voltage (for around few milliseconds). The work is mainly focused on ldquoSmall Signalrdquo open circuit Voltage Decay Method in which the intensity of light is small and the surface of solar cell is illuminated for a very small time in which minority carriers are generated in the base region of the solar cells which start recombining after switching ldquooffrdquo the light source and hence a decay curve of open circuit voltage(Voc) is obtained which is exponential in nature and from the time constant of the decay the minority carrier lifetime can be calculated. Experiment is carried out for five different samples of solar cells.