Interpenetrating heterojunction photovoltaic cells based on C60 nano-crystallized thin films

Abstract

An interpenetrating heterojunction (IHJ) structure facilitates efficient charge separation and transport in the active layer of organic photovoltaic cells (OPVs). Additionally, the recombination of generated carriers in IHJs is reduced as these networks exhibit high carrier transport with minimal recombination sites. We have developed a simple method to fabricate nanocrystallized fullerene (C60) films, which are produced by subjecting evaporated C60 films to either solvent spin-coating or solvent vapor annealing (SVA). The size of the rod-shaped nanocrystals in the films were controlled by changing the solvent and annealing time. An 80-nm-diameter size nanocrystallized C60 film that was fabricated using SVA with ethanol was incorporated as an acceptor material in an inverted IHJ OPV cell. Tetraphenyldibenzoperiflanthene (DBP) was evaporated onto the nanocrystallized C60 film as the donor material. The power conversion efficiency of an IHJ OPV cell (ITO/TiOx/nanocrystallized C60 film/DBP/MoO3/Au) increased from 1.79% to 2.12%, when compared with the conventional PHJ OPV cell. © 2016 Elsevier B.V.Embargo Period 24 month