Quantum efficiency model driven design for wide band gap gallium phosphide solar cells

The wide band gap of GaP (2.26eV) makes it a very good candidate for the top junction solar cell in a multi-junction solar cell system. A wide band gap solar cell can increase the efficiency of the system by absorbing and converting the high energy photons more efficiently. Quantum efficiency (QE) is a powerful tool in analyzing the solar cell´s performance by identifying the recombination from different regions of a solar cell. In this work, a QE model has been developed in curve fitting the measured QE curve to further analyze the solar cell and improve the solar cell design. With the continuous improved designs based on the QE analysis results, the best reported efficiency of a GaP solar cell has been achieved. This solar cell has an open circuit voltage (Voc) of 1.55V, short circuit current density (Jsc) of 1.97mA/cm², fill factor (FF) of 79.4% and efficiency of 2.42% compared to the previous best reported efficiency of 1.17%.