Quantum efficiency and temperature coefficients of GaInP/GaAs dual-junction solar cell

Abstract

GaInP/GaAs dual-junction solar cell with a conversion efficiency of 25.2% has been fabricated using metalorganic chemical vapor deposition (MOCVD) technique. Quantum efficiencies of the solar cell were measured within a temperature range from 25 to 160°C. The results indicate that the quantum efficiencies of the subcells increase slightly with the increasing temperature. And red-shift phenomena of absorption limit for all subcells are observed by increasing the cell's work temperature, which are consistent with the viewpoint of energy gap narrowing effect. The short-circuit current density temperature coefficients dJ sc/dT of GaInP subcell and GaAs subcell are determined to be 8.9 and 7.4 μA/cm2/°C from the quantum efficiency data, respectively. And the open-circuit cell voltage temperature coefficients dV oc/dT calculated based on a theoretical equation are -2.4 mV/°C and -2.1 mV/°C for GaInP subcell and GaAs subcell. © 2009 Science in China Press and Springer-Verlag GmbH.