https://ogma.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:35266 Wed 24 May 2023 12:22:28 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33914 Wed 23 Jan 2019 11:42:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33910 oc of 1.07 V. The obtained performance is one of the highest performances in inverted perovskite layouts. The cut‐price and straightforward synthesis with elegant scale up makes these classes of materials important for the industry to produce high‐throughput printed perovskite solar cells for large area applications.]]> Wed 23 Jan 2019 10:40:21 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17010 Wed 11 Apr 2018 13:30:41 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:17005 61-butyric acid methyl ester (PCBM) and P3HT:indene-C₆₀ bisadduct (ICBA) polymer solar cells, with Ca/Al and Ca/Ag cathodes and indium tin oxide/poly(ethylene-dioxythiophene):polystyrene sulfonate anode have been investigated. Degradation occurs via a combination of three primary pathways: (1) cathodic oxidation, (2) active layer phase segregation, and (3) anodic diffusion. Fully degraded devices were subjected to thermal annealing under inert atmosphere. Degraded solar cells possessing Ca/Ag electrodes were observed to regenerate their performance, whereas solar cells having Ca/Al electrodes exhibited no significant regeneration of device characteristics after thermal annealing. Moreover, the solar cells with a P3HT:ICBA active layer exhibited enhanced regeneration compared to P3HT:PCBM active layer devices as a result of reduced changes to the active layer morphology. Devices combining a Ca/Ag cathode and P3HT:ICBA active layer demonstrated ∼50% performance restoration over several degradation/regeneration cycles.]]> Wed 11 Apr 2018 10:49:00 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:21726 Wed 11 Apr 2018 09:48:50 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38133 -1 cm2 V^-1 s^-1) and significant reduction in solid-state emission quenching compared to pristine CDs; hence, it is used here as an emitting layer in both indium tin oxide (ITO)-coated glass and ITO-coated flexible poly(ethylene terephthalate) (PET) substrate OLED devices, without any hole-injection layer. The flexible OLED device exhibits a stable, voltage-independent blue/cyan emission with a record maximum luminescence of 350 cd m^-2, whereas the OLED device based on the rigid glass substrate shows a maximum luminescence of 700 cd m^-2. This work sets up a platform to develop next-generation OLED displays using CD emitters derived from the biowaste material.]]> Wed 04 Aug 2021 15:14:40 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42357 Wed 01 May 2024 16:22:39 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41883 −1 in the electrochemically doped state, whereas PTII-DT thin film prevents the macroscopic charge transport due to a large-scale crystalline disorientation. Upon evaluating both polymers as active conjugated materials in light-emitting electrochemical cells, they both exhibit emission under efficient electron/hole doping conditions.]]> Wed 01 May 2024 16:09:55 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41142 2 V⁻¹ s⁻¹, respectively. Most intriguingly, a clear charge-carrier-polarity change is observed when the devices are measured under vacuum. The pDPF-DTF2 polymer exhibits a balanced ambipolar performance with the µ_h/µ_e ratio of 1.9, whereas pDPSe-DTF2 exhibits p-type dominated charge carrier transport properties with the µ_h/µ_e ratio of 26.7. Such a charge carrier transport change is due to the strong electron-donating nature of the selenophene. Furthermore, pDPPy-DTF2 with electron-withdrawing pyridine flanking units demonstrates unipolar n-type charge transport properties with an electron mobility as high as 0.20 cm2 V⁻¹ s⁻¹. Overall, this study demonstrates a simple yet effective approach to switch the charge carrier polarity in transistors by varying the electron affinity of flanking groups of the diketopyrrolopyrrole unit.]]> Wed 01 May 2024 15:47:56 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47661 Tue 24 Jan 2023 15:33:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49156 Tue 14 Nov 2023 11:41:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37662 Tue 09 Mar 2021 18:06:04 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37228 Tue 08 Sep 2020 11:20:17 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34418 −2 cm² V s⁻¹ whereas PBIBDF-TVT polymer exhibited 5.0 × 10⁻⁴ cm² V s⁻¹. The two orders of magnitude higher electron mobility of PBIBDF-TBT over PBIBDT-TVT is a clear indicator of the better charge transport ability of this polymer semiconductor arising from its higher crystallinity and better donor–acceptor interaction.]]> Tue 03 Sep 2019 18:23:10 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:34485 Tue 03 Sep 2019 17:55:15 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:51327 Thu 31 Aug 2023 14:35:28 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47436 Thu 19 Jan 2023 17:01:34 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43296 Thu 15 Sep 2022 12:51:31 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39465 Thu 09 Jun 2022 09:22:29 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:20718 Sat 24 Mar 2018 08:06:21 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:18349 Sat 24 Mar 2018 07:52:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29631 Sat 24 Mar 2018 07:41:52 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30691 2 nanoplate photoelectrode is prepared by using a mild wet-chemical method. Depending on the calcination temperatures, SnS₂-based photoelectrodes can either retain their n-type nature with greatly enhanced anodic photocurrent density (ca. 1.2 mA cm⁻² at 0.8 V vs. Ag/AgCl) or be completely converted into p-type SnS to generate approximately 0.26 mA cm⁻² cathodic photocurrent density at −0.8 V vs. Ag/AgCl. The dominance of sulfur and tin vacancies are found to account for the dramatically different photoelectrochemical behaviors of n-type SnS₂ and p-type SnS photoelectrodes. In addition, the band structures of n-type SnS₂ and p-type SnS photoelectrodes are also deduced, which may provide an effective strategy for developing SnS₂/SnS films with controllable energy-band levels through a simple calcination treatment.]]> Sat 24 Mar 2018 07:35:09 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29355 Sat 24 Mar 2018 07:34:16 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:29678 alt-4,9-bis(2-hexyldecyl)-4,9-dihydrodithieno[3,2-c:3′,2′-h][1,5]naphthyridine-5,10-dione). Heterogeneous energy transfer is found to be crucial in the exciton dissociation process of both binary and ternary organic semiconductor systems. Circumstances favoring energy transfer across interfaces allow relaxation of the electronic energy level requirements, meaning that a cascade structure is not required for efficient ternary organic solar cells. We explain how energy transfer can be exploited to eliminate additional energy losses in ternary bulk heterojunction solar cells, thus increasing their open-circuit voltage without loss in short-circuit current. In particular, we show that it is important that the DIBSq is located at the electron donor–acceptor interface; otherwise charge carriers will be trapped in the DIBSq domain or excitons in the DIBSq domains will not be able to dissociate efficiently at an interface. KMC modeling shows that only small amounts of DIBSq (<5% by weight) are needed to achieve substantial performance improvements due to long-range energy transfer.]]> Sat 24 Mar 2018 07:32:21 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30209 Sat 24 Mar 2018 07:31:04 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29959 Sat 24 Mar 2018 07:30:59 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30009 −2 and the power efficiency of 1.5 lm W⁻¹ while that of PY-PH exhibited 2116 cd m⁻² and 0.45 lm W⁻¹ respectively.]]> Sat 24 Mar 2018 07:28:50 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:49713 500 programming and erasing cycles. Overall, this study demonstrates a charge carrier polarity change in OFETs fabricated with DPP-based dual-acceptor copolymers by incorporating various acceptors into the polymer backbone and reports a high-performance nonvolatile ambipolar flash memory.]]> Mon 29 May 2023 14:17:44 AEST ]]> 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:48733 Mon 29 Jan 2024 18:04:30 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44254 Mon 29 Jan 2024 18:04:22 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48493 Mon 29 Jan 2024 18:00:46 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:50335 Mon 29 Jan 2024 18:00:39 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:39958 L-F) has been designed and synthesized starting from a low-cost pyrene core functionalized with triphenilamine substituents at 1,3,6,8 positions (L-H), obtained via Suzuki coupling reactions. Its performance when used as green emitter in organic light emitting diodes (OLEDs) or as dopant-free hole-transporting material (HTM) in halide perovskite solar cells (PSCs) is higher than that of the L-H counterpart, in spite of its lower bulk hole-mobility (7.0 x 10⁻⁶ cm²/V) to L-H (1.9 x 10⁻⁴ cm²/V). In fact, the OLED devices based on a L-F active layer showed excellent green emission (brightness and current efficiency were 1759.8 cd/m² and 3.7 cd/A, respectively) at a 4.5 V turn-on voltage. When the molecules were employed as a dopant-free HTM in PSCs, L-F led to a power conversion efficiency (PCE) and open circuit voltage (V_oc) of 5.9% and 1.07 V, respectively, thus outperforming those of corresponding devices based on L-H (PCE = 5.0% and V_oc = 0.87 V) under similar experimental conditions (AM 1.5G and 100 mW cm²). We attribute the enhancements of L-F-based optoelectronic devices (OLEDs and PSCs) to the observed better quality of the L-F films. The promising performance of L-F indicates that fluorination of small molecules can be an effective strategy to achieve low-cost and high-performing materials for energy harvesting and display-based organic electronic devices.]]> Mon 29 Jan 2024 17:53:33 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:41684 Mon 29 Jan 2024 17:43:13 AEDT ]]> 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:13582 Mon 10 Sep 2018 13:58:00 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48833 Mon 10 Apr 2023 10:43:09 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:40285 Fri 29 Jul 2022 15:08:02 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39338 Fri 25 Aug 2023 10:12:20 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37073 b:6,5-b′]dithiophene (TPA-NADT-TPA), 4,4′-(anthracene-2,6-diyl)bis(N,N-bis(4-methoxyphenyl)aniline) (TPA-ANR-TPA) and N²,N²,N⁶,N⁶-tetrakis(4-methoxyphenyl)anthracene-2,6-diamine (DPA-ANR-DPA), are designed and synthesized for use in organic light-emitting diodes (OLEDs) and perovskite solar cells (PSCs). In OLEDs, devices based on TPA-NADT-TPA, TPA-ANR-TPA and DPA-ANR-DPA showed pure blue, blue green, and green emission, respectively. Also, the maximum brightness of the devices with a turn-on voltage of 3.8 V reached 8682 cd m⁻² for TPA-NADT-TPA, 11 180 cd m⁻² for TPA-ANR-TPA, and 18 600 cd m⁻² for DPA-ANR-DPA. These new materials are also employed as hole transporting materials (HTMs) in inverted PSCs, where they were used without additives. The inverted devices based on these HTMs achieved an overall efficiency of 10.27% for TPA-NADT-TPA, 7.54% for TPA-ANR-TPA, and 6.05% for DPA-ANR-DPA under identical conditions (AM 1.5G and 100 mW cm⁻²). While the PSCs with TPA-NADT-TPA as the HTM achieved the highest efficiency, the DPA-ANR-DPA-based OLED devices showed the brightest emission and efficiency. Based on the obtained promising performance, it is clear that this molecular design presents a new research strategy to develop materials that can be used in multiple types of devices.]]> Fri 14 Aug 2020 13:34:14 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:34115 Fri 10 Nov 2023 15:43:35 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:36858 Fri 10 Jul 2020 19:14:44 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:39081 0 is much higher and the activation energy 𝐸_𝐴 for ion hops is much lower than is seen in most other semiconductors due to the inherent softness of perovskite materials. The timescale at which the internal electric field changes due to ion motion is determined by the vacancy diffusion coefficient 𝐷_𝑣 and is similar to the timescale on which the external bias changes by a significant fraction of the open-circuit voltage at typical scan rates. Therefore, hysteresis is often observed in which the shape of the current–voltage, J–V, characteristic depends on the direction of the voltage sweep. There is also evidence that this defect migration plays a role in degradation. By employing a charge transport model of coupled ion-electron conduction in a perovskite solar cell, we show that 𝐸_𝐴 for the ion species responsible for hysteresis can be obtained directly from measurements of the temperature variation of the scan-rate dependence of the short-circuit current and of the hysteresis factor 𝐻. This argument is validated by comparing 𝐸_𝐴 deduced from measured J–V curves for four solar cell structures with density functional theory calculations. In two of these structures, the perovskite is MAPbI₃, where MA is methylammonium, CH₃NH₃; the hole transport layer (HTL) is spiro (spiro-OMeTAD, 2,2′,7,7′- tetrakis[N,N-di(4-methoxyphenyl) amino]-9,9′-spirobifluorene) and the electron transport layer (ETL) is TiO₂ or SnO₂. For the third and fourth structures, the perovskite layer is FAPbI₃, where FA is formamidinium, HC(NH₂)₂, or MAPbBr₃, and in both cases, the HTL is spiro and the ETL is SnO₂. For all four structures, the hole and electron extracting electrodes are Au and fluorine doped tin oxide, respectively. We also use our model to predict how the scan rate dependence of the power conversion efficiency varies with 𝐸_𝐴, 𝑁₀, and parameters determining free charge recombination.]]> Fri 06 May 2022 13:08:41 AEST ]]>