https://novaprd-lb.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://novaprd-lb.newcastle.edu.au/vital/access/ /manager/Repository/uon:19913 w=5–72 kg mol⁻¹). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have been used to support the STXM data. We find that unannealed P3HT:PCBM nanoparticles (NPs) exhibit a common core–shell morphology, with a PCBM-rich core and P3HT-rich shell. The morphology of the thermally annealed NP films is highly dependent upon the molecular weight of the P3HT and is determined by PCBM diffusion through the P3HT matrix. Two PCBM diffusion mechanisms operate within this system: (1) at high molecular weights diffusion of molecular PCBM dominates whilst, (2) at low molecular weights diffusion of the PCBM cores is significant. The Stokes–Einstein continuum model for diffusion has been used to determine a threshold molecular weight at which the diffusion of PCBM cores is activated in these films. The calculated value (M_w~38–25 kg mol⁻¹) is shown to agree very well with experimental observations. Finally, a model for the morphological evolution of annealed P3HT:PCBM NP films is developed.]]> Sat 24 Mar 2018 08:03:45 AEDT ]]> https://novaprd-lb.newcastle.edu.au/vital/access/ /manager/Repository/uon:21024 w), was used to prepare P3HT: phenyl C61 butyric acid methyl ester (PCBM) nanoparticulate organic photovoltaic (NP OPV) devices and the effect of this variation on device performance is reported. Power conversion efficiency (PCE) is observed to peak for the mid-range of molecular weights tested, this behaviour varies from the trend generally observed with bulk heterojunction (BHJ) devices, where high molecular weight polymers deliver the highest PCEs. Here we demonstrate that polymer molecular weight affects the electronic, morphological and compositional structure of the nanoparticulate film. Significantly, it is the domain composition that is most highly correlated with device performance and this composition is driven by the PCBM mobility and aggregation within the nanoparticulate structure.]]> Fri 02 Sep 2022 11:14:24 AEST ]]>