Manipulating Nanowires in Interconnecting Layer for Efficient Tandem Organic Photovoltaics

Owing to the function of manipulating light absorption distribution, tandem organic solar cells containing multiple sub-cells exhibit high power conversion efficiencies. However, there is a substantial challenge in precisely controlling the inter-subcells carrier migration which determines the balance of charge transport across the entire device. The conductivity of "nanowires"-like conducting channel in interconnecting layer between sub-cells should be improved which calls for fine engineering on the morphology of polyelectrolyte in interconnecting layer. Here, we develop a simple method to effectively manipulating the domains of conductive components in commercially available polyelectrolyte PEDOT:PSS. The use of poor solvent could effectively modify the configuration of polystyrene sulfonic acid and thus the space for conductive components. Based on our strategy, the insulated shells wrapping conductive domains are thinned and the efficiencies of tandem organic solar cells are improved. We believe our method might provide guidance for the manufacture of tandem organic solar cells.