Fabrication of asymmetric heterojunction carrier selective c-Si solar cell

In this paper, we report the fabrication of heterojunction carrier selective c-Si solar cell using a hole selective poly – 3,4 ethylene dioxythiophene (PEDOT:PSS) and an electron selective magnesium fluoride (MgF2) layers. Dopant- free asymmetric heterojunction solar cells (DASH cells) based on c-Si have gained considerable attention due to low-cost fabrication methods and ease of fabrication techniques. Carrier selective contact (CSC) based solar cells can reduce the interface recombination by selectively allowing only one type of carriers to pass through the selective layers. Here, solution-processed hole selective PEDOT:PSS was spin-coated on the c-Si, while the electron selective MgF2 layer was deposited by thermal evaporation technique. The conductivity of the PEDOT:PSS film was enhanced using secondary solvent doping with DMSO. The thickness of the MgF2 layer was optimized using the transmission line measurement. The dipole behavior of MgF2 would result in a decrease in the effective work function of the MgF2/metal stack. The as- fabricated solar cell showed a power conversion efficiency of 7.6% with an open-circuit voltage of 550 mV and a short circuit current of 31 mA/cm2.