A universal method for constructing high efficiency organic solar cells with stacked structures

Abstract

Constructing organic solar cells with stacked structures by sequential deposition (SD) of donor and acceptor film has great potential in industrial production, since it demonstrated little dependence on the ratio of donor and acceptor materials, solvents, and additives. Herein, we presented an eco-friendly solvents protection (ESP) method for fabricating high-performance OSCs with stacked structures. Several non-aromatic and non-halogenated solvents were employed as protective agents to build SD devices with a configuration of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate (PEDOT:PSS Clevios P VP Al 4083)/donor/protective solvent/acceptor/perylene diimide functionalized with amino N-oxide (PDINO)/Al, which showed that n-octane is the optimal choice for SD devices. Eight different SD systems including fullerene and nonfullerene ones presented comparable photovoltaic performance to their BC counterparts, which proved the universality of this ESP method. Significantly, the devices of ITO/PEDOT:PSS/D18/N3/PDINO/Al with n-octane as the protective solvent achieved a maximum PCE of 17.52%, which is the record efficiency of SD devices. Furthermore, a protective factor (δ) was proposed to demonstrate quantitative relationship between δ and PCE after experimental and theoretical investigation, which presented an idea to understand the mechanism and provide a guideline for solvent choices.