Highly transparent antireflection coatings on fullerene-free organic solar cells using polymeric nanoparticles

Abstract

A simple method is described herein for the preparation of highly transparent antireflection (AR) coatings based on polymeric nanoparticles (NPs) for efficient organic solar cells. The NPs based on poly(styrene-co-acrylic acid) (PS-co-PAA) are synthesized via a straightforward emulsion polymerization process, and air void-containing AR films are deposited onto the glass sides of organic solar cells via spin-casting of the NP solution. Various NP sizes ranging from 42 to 86 nm are used to provide a variety of pore fractions and refractive indices. The AR film with an average particle size of 86 nm is shown to increase the normal-incident 595-nm light transmittance from 92.0 to 98.9%. The AR coatings on solar cells are beneficial for the light absorption of the photoactive layers, thus resulting in enhanced short-circuit current densities of up to ∼26.8 mA cm-2. The power conversion efficiency of the device with the optimum AR coating is increased to 12.8% compared to that of non-AR device (12.0%). This work represents a simple strategy for developing high-performance solar cells.