https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 Vertical and lateral morphology effects on solar cell performance for thiophene-quinoxaline copolymer: PC₇₀BM blend https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:16996 71-butyric acid methyl ester (PC70BM). We have investigated the lateral morphology using atomic force microscopy (AFM) and scanning transmission X-ray microscopy (STXM), the vertical morphology using dynamic secondary ion mass spectrometry (d-SIMS) and variable-angle spectroscopic ellipsometry (VASE), and the surface composition using near-edge X-ray absorption fine structure (NEXAFS). The lateral phase-separated domains observed in films spincoated from single solvents, increase in size with increasing solvent vapour pressure and decreasing PC70BM solubility, but are not observed when 1-chloronaphthalene (CN) is added. A strongly TQ1-enriched surface layer is formed in all TQ1:PC70BM blend films and rationalized by surface energy differences. The photocurrent and power conversion efficiency strongly increased upon the addition of CN, while the leakage current decreased by one to two orders of magnitude. The higher photocurrent correlates with the finer lateral structure and stronger TQ1-enrichment at the interface with the electron-collecting electrode. This indicates that the charge transport and collection are not hindered by this polymer-enriched surface layer. Neither the open-circuit voltage nor the series resistance of the devices are sensitive to the differences in morphology.]]> Wed 11 Apr 2018 15:49:57 AEST ]]> Diketopyrrolopyrrole-based polymer:fullerene nanoparticle films with thermally stable morphology for organic photovoltaic applications https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:34547 alt-naphthalene}):PC₇₁BM ([6,6]-phenyl C₇₁ butyric acid methyl ester) NP system and then compare the thermal stability of NP and BHJ films to the common poly(3-hexylthiophene) (P3HT): phenyl C₆₁ butyric acid methyl ester (PC₆₁BM) system. We find that material Tg plays a key role in the superior thermal stability of the PDPP-TNT:PC₇₁BM system; whereas for the P3HT:PC₆₁BM system, domain structure is critical.]]> Tue 26 Mar 2019 13:54:33 AEDT ]]> X-ray spectromicroscopy of polymer/ fullerene composites: quantitative chemical mapping https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:994 Sat 24 Mar 2018 08:29:51 AEDT ]]> Nano-domain behaviour in P3HT: PCBM nanoparticles, relating material properties to morphological changes https://nova.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 (Mw~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 ]]> Determining the structural motif of P3HT:PCBM nanoparticulate organic photovoltaic devices https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19663 Sat 24 Mar 2018 08:01:11 AEDT ]]> Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10nm length scales https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:17883 Sat 24 Mar 2018 07:56:19 AEDT ]]> Surfactant-free nanoparticulate organic photovoltaics https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:21317 Sat 24 Mar 2018 07:52:52 AEDT ]]> The role of miscibility in polymer:fullerene nanoparticulate organic photovoltaic devices https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:19348 Sat 24 Mar 2018 07:52:11 AEDT ]]> The effect of mesomorphology upon the performance of nanoparticulate organic photovoltaic devices https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:27964 Sat 24 Mar 2018 07:38:45 AEDT ]]> Probing the origin of photocurrent in nanoparticulate organic photovoltaics https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:26612 Sat 24 Mar 2018 07:34:00 AEDT ]]> Nano-pathways: bridging the divide between water-processable nanoparticulate and bulk heterojunction organic photovoltaics https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:28349 g) and amorphous nature, compared to the commonly applied semicrystalline polymer poly(3-hexylthiophene) (P3HT). This study reports the optimisation of TQ1:PC71BM (phenyl C71 butyric acid methyl ester) NP-OPV device performance by the application of mild thermal annealing treatments in the range of the Tg (sub-Tg and post-Tg), both in the active layer drying stage and post-cathode deposition annealing stage of device fabrication, and an in-depth study of the effect of these treatments on nanoparticle film morphology. In addition, we report a type of morphological evolution in nanoparticle films for OPV active layers that has not previously been observed, that of PC71BM nano-pathway formation between dispersed PC71BM-rich nanoparticle cores, which have the benefit of making the bulk film more conducive to charge percolation and extraction.]]> Sat 24 Mar 2018 07:25:10 AEDT ]]> A multilayered approach to polyfluorene water-based organic photovoltaics https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:23616 Sat 24 Mar 2018 07:13:27 AEDT ]]> Nanomorphology of eco-friendly colloidal inks, relating non-fullerene acceptor surface energy to structure formation https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39326 −2) and eh-IDTBR (18.3 mJ m−2). This article is the first report of a flipped nanoparticle core–shell morphology comprising an NFA-rich shell for the miniemulsion synthesis route. The composition of the shells and cores was able to be controlled by the differential mismatch in the surface energy of the donor and acceptor materials, with ΔGsurface > 0, ΔGsurface = 0, and ΔGsurface < 0 for acceptor core–donor shell, molecularly intermixed, and acceptor shell–donor core, respectively. Accordingly, we introduce an entirely overlooked new figure of merit (FoM) for customizing nanoparticulate colloidal inks: tunable surface energy of non-fullerene-based semiconductors. The establishment of this FoM opens up electroactive material design to a wide range of functional printing applications with varying device and ink structure requirements, thereby reshaping the nanoengineering toolkit for waterborne colloidal dispersions and hence printed electronics.]]> Mon 29 Jan 2024 18:52:33 AEDT ]]> Unravelling donor-acceptor film morphology formation for environmentally-friendly OPV ink formulations https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:46422 rational choice of solvent approach as opposed to the usual trial-and-error methods. We demonstrate here that we can achieve a bicontinuous interpenetrating network with nanoscale phase separation for the chosen donor–acceptor material system poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl]:phenyl-C61 butyric acid methyl ester (TQ1:PC61BM) when processing from green solvent ink formulations. This structure is achieved by first calculating the Hansen solubility parameters (HSP) of the donor and acceptor materials, followed by careful choice of solvents with selective relative solubilities for the two materials based on the desired order of precipitation necessary for forming a nanostructured interdigitated network morphology. We found that the relative distances in Hansen space (Ra) between TQ1 and the primary solvent, on the one hand, and PC61BM and the primary solvent, on the other hand, could be correlated to the donor–acceptor morphology for the formulations based on the solvents d-limonene, anisole, and 2-methyl anisole, as well as the halogenated reference solvent o-dichlorobenzene. This nanostructured blend film morphology was characterised with scanning transmission X-ray microscopy (STXM) and transmission electron microscopy (TEM), and the film surface composition was analysed by near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Hansen solubility theory, based on solution thermodynamics, has been used and we propose an HSP-based method that is a general platform for the rational design of ink formulations for solution-based organic electronics, in particular facilitating the green solvent transition of organic photovoltaics. Our results show that the bulk heterojunction morphology for a donor–acceptor system processed from customised solvent mixtures can be predicted by the HSP-based method with good reliability.]]> Mon 29 Jan 2024 18:05:22 AEDT ]]> Building intermixed donor-acceptor architectures for water-processable organic photovoltaics https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:48733 Mon 29 Jan 2024 18:04:30 AEDT ]]> Manipulating nanoscale structure to control functionality in printed organic photovoltaic, transistor and bioelectronic devices https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:37227 Fri 11 Sep 2020 09:08:48 AEST ]]>