https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47083 Wed 28 Feb 2024 14:49:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:52321 Wed 21 Feb 2024 14:42:46 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:51668 Wed 14 Feb 2024 15:32:22 AEDT ]]> https://ogma.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 ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21974 Wed 11 Apr 2018 09:17:14 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:54536 Tue 27 Feb 2024 20:42:40 AEDT ]]> https://ogma.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 T_g 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 ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37268 Tue 15 Sep 2020 14:57:28 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34668 60 multiadducts (ICxA), through two purification processes: centrifugal and crossflow ultrafiltration. The impact of purification is twofold: firstly, removal of excess sodium dodecyl sulfate (SDS) surfactant from the ink and, secondly, concentration of the photoactive components in the ink. The removal of SDS was studied in detail both by a UV–vis spectroscopy-based method and by surface tension measurements of the nanoparticle ink filtrate; revealing that centrifugal ultrafiltration removed SDS at a higher rate than crossflow ultrafiltration even though a similar filter was applied in both cases (10,000 Da M_w cut-off). The influence of SDS concentration on the aqueous solar nanoparticle (ASNP) inks was investigated by monitoring the surface morphology/topography of the ASNP films using atomic force microscopy (AFM) and scanning electron microscopy (SEM) and photovoltaic device performance as a function of ultrafiltration (decreasing SDS content). The surface morphology/topography showed, as expected, a decreased number of SDS crystallites on the surface of the ASNP film with increased ultrafiltration steps. The device performance revealed distinct peaks in efficiency with ultrafiltration: centrifuge purified inks reached a maximum efficiency at a dilution factor of 7.8 × 10⁴, while crossflow purified inks did not reach a maximum efficiency until a dilution factor of 6.1 × 10⁹. This difference was ascribed to the different wetting properties of the prepared inks and was further corroborated by surface tension measurements of the ASNP inks which revealed that the peak efficiencies for both methods occurred for similar surface tension values of 48.1 and 48.8 mN m⁻¹. This work demonstrates that addressing the surface tension of large-volume ASNP inks is key to the reproducible fabrication of nanoparticle photovoltaic devices.]]> Tue 03 Sep 2019 17:59:41 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31411 70BM formed during the transfer of spin-coated polymer:PC₇₀BM blend films onto Cu-grids lead to an underestimation of PC₇₀BM/polymer concentration ratios. Finally, we show that the selective degradation of one of the components can impair the accurate determination of local blend composition.]]> Sat 24 Mar 2018 08:45:15 AEDT ]]> https://ogma.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://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18538 Sat 24 Mar 2018 07:50:11 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:27964 Sat 24 Mar 2018 07:38:45 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26612 Sat 24 Mar 2018 07:34:00 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29716 -3. By applying the critical radius of nucleation for PCBM and the Stokes-Einstein equation for mobility of PCBM in a P3HT matrix, a model is developed which explains the formation of both crystallites and aggregates.]]> Sat 24 Mar 2018 07:33:24 AEDT ]]> https://ogma.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 T_g (sub-T_g and post-T_g), 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 ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:22221 Sat 24 Mar 2018 07:17:44 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24727 SC and efficiency. Overall, this work shows that the nanoparticle approach provides a new experimental lever for morphology control in OPV devices.]]> Sat 24 Mar 2018 07:10:59 AEDT ]]> https://ogma.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 ΔG_surface > 0, ΔG_surface = 0, and ΔG_surface < 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 ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39622 Mon 29 Jan 2024 18:49:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:52029 Mon 29 Jan 2024 18:35:17 AEDT ]]> https://ogma.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 (R_a) 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 ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48733 Mon 29 Jan 2024 18:04:30 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41163 Mon 29 Jan 2024 17:57:01 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44553 Mon 29 Jan 2024 17:56:34 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37152 Mon 24 Aug 2020 11:10:54 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42346 Mon 22 Aug 2022 13:54:26 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:51565 Mon 11 Sep 2023 14:22:38 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44176 Mon 10 Oct 2022 10:13:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38868 Fri 25 Mar 2022 11:12:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:35933 alt-5,10-bis((2-hexyldecyl)oxy)dithieno[3,2-c:3',2'-h][1,5]naphthyridine-2,7-diyl] (PTNT) and fullerene blend utilizing chloroform as well as a non-chlorinated and environmentally benign solvent, o-xylene, as the miniemulsion dispersed phase solvent. The nanoparticles (NPs) in the solid-state film were found to coalesce and offered a smooth surface topography upon thermal annealing. Organic photovoltaics (OPVs) with photoactive layer processed from the nanoparticle dispersions prepared using chloroform as the miniemulsion dispersed phase solvent were found to have a power conversion efficiency (PCE) of 1.04%, which increased to 1.65% for devices utilizing NPs prepared from o-xylene. Physical, thermal and optical properties of NPs prepared using both chloroform and o-xylene were systematically studied using dynamic mechanical thermal analysis (DMTA) and photoluminescence (PL) spectroscopy and correlated to their photovoltaic properties. The PL results indicate different morphology of NPs in the solid state were achieved by varying miniemulsion dispersed phase solvent.]]> Fri 19 Jun 2020 12:14:42 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42295 Fri 19 Aug 2022 14:58:40 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49941 Fri 16 Jun 2023 09:51:41 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37227 Fri 11 Sep 2020 09:08:48 AEST ]]> https://ogma.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 ]]>