Three terminal Si-Si:Ge solar cells

A 3-terminal Si-Si:Ge tandem solar cell, which consists of a top silicon solar cell and a bottom Si:Ge solar cell sharing a common base, has been designed and fabricated. This solar cell is designed to replace standalone Si solar cell and Si:Ge solar cell in a multi-junction solar cell system in order to simplify the module, improve its performance and reduce its cost. Initial results show that both Si solar cells and Si:Ge solar cells in this structure can achieve good performance. The best Si solar cell shows a Voc 598.5mV, Jsc 22.9mA/cm² and FF 77.3% under one sun, best Si:Ge solar cell shows a Voc 189mV and Jsc 3.26mA/cm² below silicon filter. None of these solar cells have anti-reflection coatings.