16% efficient silicon/organic heterojunction solar cells using narrow band-gap conjugated polyelectrolytes based low resistance electron-selective contacts

Dopant-free silicon (Si)/organic heterojunction solar cells have drawn much attention due to their immense potential in achieving high power conversion efficiencies. In this paper, Narrow band-gap conjugated polyelectrolyte, PTB7-NBr, is firstly used as cathode interlayer to improve the contact property of n-Si/Al, as well as the electron transporting property, leading to an ultralow contact resistivity of 6.7 ± 0.8 mΩ cm2. N-Si/PEDOT:PSS heterojunction solar cells with remarkable power conversion efficiency of 16.0% is finally achieved by employing n-Si/PTB7-NBr/Al as electron-selective contact.195