Aim: Increasing the energy conversion effciency of organic nanostructured bulk heterojunction photovoltaic devices, improving the stability of their nanomorphology. Methods: organic multijunction approaches, introduction of metallic nanopartikels or nanoshells for light-scattering and plasmonic effects. The tasks of UGent is modelling: guidelines for nanoparticle size, geometry, coverage, passivation and functionalization device modelling of organic polymer cell structures, single and multi-junction.