Brief Outlook on Top Cell Absorber of Silicon-Based Tandem Solar Cells

Silicon (Si) is a low-cost, stable photovoltaic market contributor which is approaching its single-junction theoretical efficiency limit. To further elevate the efficiency of crystalline Si (c-Si) afterward, Si solar cells (SCs) need a proper top cell absorber in Si tandem SCs. Herein, the top cell absorber is studied by evaluating their current state of the art, the existing challenges, and possible future solutions which can enhance their efficiency. The progress of perovskite/Si tandem SC both for monolithic and four terminals is exceptional but still many challenges limit their commercialization. In view of these challenges, the relative's solutions are prescribed in detail to make possible their realization. III-V semiconductors being mature candidates still face a growth/fabrication problem, which makes them a costly option for III-V/Si tandem SCs. Effective growth strategies along with technical solutions are discussed in detail. Emerging chalcogenides are considered the future of tandem technology. Recent developments in the chalcogenides/Si tandem SC are highlighted and the possible options are presented. In the end, a short note is given on the near future tandem materials for Si tandem SCs.