Contact-printed ultrathin siloxane passivation layer for high-performance Si-PEDOT:PSS hybrid solar cells

Abstract

A simple way for high-performance planar Si-PEDOT:PSS hybrid solar cells have been demonstrated in this work. Contact-printed, hydrophobically-recovered ultrathin siloxane layer has been employed as insertion layers at interfaces in Si-PEDOT:PSS hybrid solar cells. The printing has been done at room ambient in dry state for 5–10min, which has led to <0.5nm thin siloxane layer at interfaces. The printed ultrathin siloxane plays the role of passivation layer and significantly increases the photocurrent by suppressing charge carrier recombination at interfaces, leading to >13% cell efficiency with non-textured planar Si substrate. Interestingly, the layer has been found to be equally effective at both interfaces (‘top’ interface between Si and PEDOT:PSS, and ‘bottom’ interface between Si and bottom electrode), while other insertion layers suggested in literature works at one interface only. Furthermore, the sheet resistance of PEDOT:PSS layer, rather than resistivity or conductivity, has been found to be the relevant characteristics in the hybrid solar cells, because the carrier conduction in 2-dimension is utmost importance in such devices. The suggested method can be a valuable help for low-cost, high-performance Si-PEDOT:PSS hybrid solar cells and can expedite the commercialization of the hybrid photovoltaics in near future.