Achieving low contact resistivity in PEDOT:PSS/n-Si solar cells

Abstract Good conductivity and transparency in the visible spectrum along with low processing temperatures and ease of fabrication make Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) a widely accepted polymer for organic-inorganic hybrid heterojunction solar cells. Although the overall conductivity of the PEDOT:PSS is high, the PSS segregates more at the surfaces of the deposited film. This leads to high contact resistivity of PEDOT:PSS film with metal and silicon. In this report, we explore the effect of the spin coating rates on the contact resistivity of PEDOT:PSS with the metal and silicon and the associated performance of PEDOT:PSS/n-Si solar cells. Two different spin speeds of 1000 rpm and 4000 rpm were used to deposit the PEDOT:PSS films over silicon. The PEDOT:PSS films were also deposited in single- and double-layer forms. We could achieve very low contact resistivity of PEDOT:PSS with silicon through spin speed optimizations. Hence, the overall performance of the PEDOT:PSS/n-Si solar cells improves with the spin speed for both single- and double-layer PEDOT:PSS film depositions.