SASTech - Technical Journal of RUAS

Polycrystalline thin film solar cells made of Copper Indium Gallium Diselenide (CIGS) and CdTe/CdS are attractive for space applications because of their lower cost, flexibility, light weight and high specific power. One of the important requirements of solar cells for space applications is stability against particle irradiation. High energy particle radiation in outer space produces defects in semiconductors that cause a reduction in solar cell power output. The concept of damage equivalent 1 MeV electron fluence requires some method of evaluating the damage effectiveness of electrons of various energies. On the basis of experimental data, one can therefore define a relative damage effectiveness for each electron energy which will be a measure of the ratio of that electron fluence at a given energy to the 1 MeV electron fluence necessary to degrade a solar cell to the same output parameter value. In this paper the results of the study on the effect of 8MeV electron irradiation on the electrical characteristics of CIGS and CdTe/CdS polycrystalline thin-film solar cells is compared and presented. Current-Voltage (I-V) characteristics of the cells under AM 1.5 illumination condition and capacitance-frequency measurements were carried out before and after irradiation. Solar cell parameters like short circuit current (Isc), open circuit voltage (Voc), fill factor (FF), and efficiency () were calculated from these I-V characteristics. It is found that the efficiency of the CIGS and CdTe/CdS solar cells decreases with increase in electron dose. The other cell parameters such as FF and Voc do not seem to be affected much by irradiation.