Controlled dispersion of polystyrene‐capped Au nanoparticles in P3HT:PC61BM and consequences upon active layer nanostructure. Issue 7 (26th November 2015) - Butcher, Dennis P.
ABSTRACT: Numerous recent publications detail higher absorption and photovoltaic performance within organic photovoltaic (OPV) devices which are loaded with Au or Ag nanoparticles to leverage the light management properties of the localized surface plasmon resonance (LSPR). This report details the impact upon film morphology and polymer/nanoparticle interactions caused by incorporation of polystyrene‐coated Au nanoparticles (Au/PS) into the P3HT:PC61 BM bulk heterojunction film. Nanostructural analysis by transmission electron microscopy and X‐ray scattering reveals tunable Au/PS particle assembly that depends upon the choice of casting solvent, polymer chain length, film drying time, and Au/PS particle loading density. This Au/PS particle assembly has implications on the spectral position of the Au nanoparticle LSPR, which shifts from 535 nm for individually dispersed particles in toluene to 650 nm for particles arranged in large clusters within the P3HT:PC61 BM matrix. These results suggest a critical impact from PS/P3HT phase separation, which causes controlled assembly of a separate Au/PS phase in the nanoparticle/OPV composite; controlled Au/PS phase formation provides a blueprint for designing AuNP/OPV hybrid films that impart tunable optical behavior and potentially improve photovoltaic performance. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.2016, 54, 709–720 Abstract : Au nanoparticles with a polymer coating assemble into three‐dimensional ordered structures, dependent upon processing conditions, which impact film structure and the electronic and optical properties when placed into an organic photovoltaic active layer. The accompanying figure provides a three‐dimensional reconstruction of polymer coated Au nanoparticles within the active layer of an organic photovoltaic active layer film.