Research on monolithic AlGaInP/AlGaInAs/GaInAs/Ge quadruple-junction solar cell for high efficiency lattice-matched tandem photovoltaic device

This is the authors' abstract. We don't add key points for this paper.

Lattice-matched AlGaInP/AlGaInAs/GaInAs/GaInNAs(Sb)/Ge five-junction (5J) solar cell can be expected to achieve a practical efficiency high as 36% under the air mass (AM0) spectrum. In this work, AlGaInP/AlGaInAs/GaInAs/Ge quadruple-junction (4J) cells and relevant subcells are investigated as research foundation of Ge-based 5J device. An efficiency of 4J cell is obtained as 30.45% (AM0, 25 °C), with short-circuit current density (JSC), open-circuit voltage (VOC), and fill factor (FF) as 11.78 mA cm−2, 4.131 eV, and 85.5%, respectively. The JSC is close to the demand of 5J device with 36% efficiency, the high VOC and FF indicates a good material quality of 4J solar cell.