Temperature Dependence of the IV Parameters from Triple Junction GaInP/InGaAs/Ge Concentrator Solar Cells

Results are reported for the temperature dependence of the IV parameters as a function of concentration level for triple junction (3J), GaInP/GaAs/Ge concentrator solar cells measured outdoors. Each IV parameter was measured in the range from 1 to 950 suns. The temperature coefficient of V_oc, dV_oc/dT, showed an abrupt decrease at low concentration but then decreased slowly at mid concentration for which a steady value was reached at higher concentration. In this latter case, the generation of minority carriers from high injection conditions overcomes the effects of the dark saturation current. The characteristics of the temperature coefficient of J_sc, dJ_sc/dT, however, are primarily dependent on high injection conditions coupled by the influence of the subcell that limits the current in the 3J cell stack. It is suggested the subcell that limits the device current is also influenced by chromatic aberration effects from the Fresnel lens. Values for dV_oc/dT and dJ_sc/dT as a function of the concentration ratio are presented