Ionic silsesquioxane-capped gold nanoparticle powders presenting narrow size distribution were synthesised, characterised and applied in the assembly of organic solar cells. The assembled devices were electrically modelled, and the nanoparticles encapsulated with a charged pendant silsesquioxane were found to provide enhanced photocurrent, and to result in better electrical properties than those capped with bridged double-charged silsesquioxane. Therefore, thinner layers of encapsulation result in higher efficiency. (C) 2017 Elsevier B.V. All rights reserved.