Monolithic 24  cm2 flexible triple-junction solar cell encapsulated module based on the ipsilateral electrode welding technology

The inverted metamorphic multi-junction solar cell is anticipated to be widely applied in stratospheric flight because of its exceptional properties of flexibility and light weight. We propose an ipsilateral welding technology based on Ti/Au electrodes to simplify the fabrication process of GaInP/GaAs/InGaAs solar cells and encapsulate large-sized flexible solar cells. After annealing at 200°C for 2 h, the Ti/Au electrode achieved a low specific contact resistivity of 2.9×10 −7 Ω⋅cm 2 . The performance of the ohmic contact remains stable after the thermal cycling tests. The Ti/Au electrode can require less heat input for welding to reduce the risk of microcrack formation of the solar cells. By employment of this electrode, a 24cm 2 solar cell achieved a conversion efficiency of 34.74%. A flexible solar cell module with an efficiency of 32.82% under AM 1.5G illumination was obtained by the ipsilateral electrode welding technology.