Can Laminated Carbon Challenge Gold? Toward Universal, Scalable, and Low-Cost Carbon Electrodes for Perovskite Solar Cells

While perovskite solar cell (PSC) efficiencies are soaring at a laboratory scale, these are most commonly achieved with evaporated gold electrodes, which would present a significant expense in large-scale production. This can be remedied through the use of significantly cheaper carbon electrodes that, in contrast to metals, also do not migrate through the device. To this end, the present work investigates simple-to-prepare aluminum-supported carbon electrodes derived from commercially available, inexpensive materials that can be applied onto various hole-transporting materials and enable photovoltaic performances on par with those provided by gold electrodes. Successful integration of the new carbon-based electrode into flexible devices produced by a roll-to-roll printing technology by both pressing and lamination is demonstrated. However, temperature cycling durability tests reveal that the use of carbon electrodes based on commercial pastes is hindered by incompatibility of adhesive additives with the key components of the PSCs under heating. Resolving this issue, tailor-made graphite electrodes devoid of damaging additives are introduced, which improve the PSC stability under temperature cycling test protocol to the level provided by benchmark gold electrodes. The study highlights current challenges in developing laminated carbon electrodes in PSCs and proposes strategies toward the resolution thereof.This work was funded by the Australian Centre for Advanced Photovoltaics and Australian Renewable Energy Agency. A.N.S. also acknowledges the financial support from the Australian Research Council (Centre of Excellence CE140100012; Future Fellowship FT200100317). Monash Centre for Electron Microscopy (MCEM) and Melbourne Centre for Nano fabrication (MCN) are acknowledged for providing access to their facilities. The authors are grateful to Dr T. Zhang, A. Surmiak, Dr. N. Peris, Dr. D. Senevirathna, and Dr. N. Pai from Monash University for the experimental support throughout this study

One-step Preparation of ZnO Electron Transport Layers Functionalized with Benzoic Acid Derivatives

We present a "one-step" approach to modify ZnO electron transport layers (ETLs) used in organic solar cells. This approach involves adding benzoic acid (BZA) derivatives directly to the ZnO precursor solution, which are then present at the surface of the resulting ZnO film. We demonstrate this approach for three different BZA derivatives, namely benzoic acid, chlorobenzoic acid, and 4-hydrazinobenzoic acid. For all molecules, improved device performance and stability is demonstrated in solar cells using an active layer blend of PTQ10 (donor) and ITIC-Br (non-fullerene acceptor) compared to such cells prepared using untreated ZnO. Furthermore, similar or improved device performance and stability is demonstrated compared to conventional PEIE treatment of ZnO. The presence of the BZA derivatives at the surface after processing is established using X-ray photoelectron spectroscopy and near-edge X-ray absorption fine-structure spectroscopy. From atomic force microscopy analysis and X-ray diffraction studies, the addition of BZA derivatives appears to restrict ZnO grain growth; however, this does not negatively impact device performance. ZnO layers treated with BZA derivatives also exhibit higher water contact angle and lower work function compared to untreated ZnO. This approach enables simplification of device manufacture while still allowing optimization of the surface properties of metal oxide ETLs. Keywords: electron transport layers, zinc oxide, organic solar cells, surface modificationComment: Manuscript: 25 pages, 8 figures, 5 tables. Supplementary Material: 36 pages, 22 figures, 13 tables. Submitted to Solar Energy Materials and Solar Cell

Solution processable direct bandgap copper-silver-bismuth iodide photovoltaics : compositional control of dimensionality and optoelectronic properties

Altres ajuts: SRR acknowledges the support from "laCaixa" Foundation (ID 100010434; LCF/BQ/PI20/11760024). Open access publishing facilitated by Monash University, as part of the Wiley - Monash University agreement via the Council of Australian University Librarians.The search for lead-free alternatives to lead-halide perovskite photovoltaic materials resulted in the discovery of copper(I)-silver(I)-bismuth(III) halides exhibiting promising properties for optoelectronic applications. The present work demonstrates a solution-based synthesis of uniform CuAgBiI thin films and scrutinizes the effects of x on the phase composition, dimensionality, optoelectronic properties, and photovoltaic performance. Formation of pure 3D CuAgBiI at x = 1, 2D CuAgBiI at x = 2, and a mix of the two at 1 < x < 2 is demonstrated. Despite lower structural dimensionality, CuAgBiI has broader optical absorption with a direct bandgap of 1.89 ± 0.05 eV, a valence band level at -5.25 eV, improved carrier lifetime, and higher recombination resistance as compared to CuAgBiI. These differences are mirrored in the power conversion efficiencies of the CuAgBiI and CuAgBiI solar cells under 1 sun of 1.01 ± 0.06% and 2.39 ± 0.05%, respectively. The latter value is the highest reported for this class of materials owing to the favorable film morphology provided by the hot-casting method. Future performance improvements might emerge from the optimization of the CuAgBiI layer thickness to match the carrier diffusion length of ≈40-50 nm. Nonencapsulated CuAgBiI solar cells display storage stability over 240 days

Midwives’ experiences of cultural competency training and providing perinatal care for migrant women a mixed methods study: Operational Refugee and Migrant Maternal Approach (ORAMMA) project

Abstract: Background: The number of international migrants continues to increase worldwide. Depending on their country of origin and migration experience, migrants may be at greater risk of maternal and neonatal morbidity and mortality. Having compassionate and culturally competent healthcare providers is essential to optimise perinatal care. The “Operational Refugee and Migrant Maternal Approach” (ORAMMA) project developed cultural competence training for health professionals to aid with providing perinatal care for migrant women. This presents an evaluation of ORAMMA training and explores midwives’ experiences of the training and providing care within the ORAMMA project. Methods: Cultural competence was assessed before and after midwives (n = 35) received ORAMMA compassionate and culturally sensitive maternity care training in three different European countries. Semi-structured interviews (n = 12) explored midwives’ experiences of the training and of caring for migrant women within the ORAMMA project. Results: A significant improvement of the median score pre to post-test was observed for midwives’ knowledge (17 to 20, p < 0.001), skills (5 to 6, p = 0.002) and self-perceived cultural competence (27 to 29, p = 0.010). Exploration of midwives’ experiences of the training revealed themes of “appropriate and applicable”, “made a difference” and “training gaps” and data from ORAMMA project experiences identified three further themes; “supportive care”, “working alongside peer supporters” and “challenges faced”. Conclusions: The training improved midwives’ knowledge and self-perceived cultural competence in three European countries with differing contexts and workforce provision. A positive experience of ORAMMA care model was expressed by midwives, however clearer expectations of peer supporters’ roles and more time within appointments to assess the psychosocial needs of migrant women were desired. Future large-scale research is required to assess the long-term impact of the ORAMMA model and training on practice and clinical perinatal outcomes

Naphthalene-imide Self-assembled Monolayers as a Surface Modification of ITO for Improved Thermal Stability of Perovskite Solar Cells [Dataset]

38 pages. -- 1. Thermal Properties. -- 2. Cyclic Voltammetry. -- 3. Optical Characterization. -- 4. Energy Level Diagram. -- 5. Self-Assembly. -- 6. Water Contact Angle Measurements. -- 7. XPS Measurements. -- 8. Perovskite Solar Cells. -- 9. Surface Recombination Velocity Measurements. -- 10. Drift-Diffusion Simulations. -- 11. Shelf-Life Stability. -- 12. Synthesis. -- 12.1. Naphthalene monoimides 2a-2d. -- 12.2. Naphthalene diimides 3a-3d. -- 13. ReferencesElectron-transport-layer-free (ETL-free) perovskite solar cells (PSCs) show great promise for commercialization due to their simple design and ease of fabrication. However, the interface between the transparent conductive oxides such as indium-doped tin oxide (ITO) and the perovskite is not optimal due to differences in their work functions, surface defects, and wettability of the substrates. Surface modification of ITO through self-assembled monolayers (SAMs) to get ITO/SAM charge selective layers has shown great improvement in device performance in recent years, but little emphasis has been put on the stability of these devices. Here, we address this gap by introducing a series of newly synthesized naphthalene-imide derivatives which self-assemble at the interface between ITO and the perovskite interface and study their impact on the thermal stability of triple-cation PSCs. The chemical and thermal stabilities of the naphthalene-imide SAMs help improve the thermal stability of the devices, reaching T80 lifetimes exceeding 800 h for devices containing a pyridine-functionalized naphthalene diimide carboxylic acid at 85 °C in air. In addition, all SAMs improve the stabilized power output of the devices with respect to ITO-only reference devices. Drift-diffusion simulations reveal the strong influence of the ITO work function on the efficiency in ETL-free devices, and a work function reduction of 0.2 eV could improve efficiencies by over 30%. The functional diversity of naphthalene imides coupled with the ease of SAM deposition opens a pathway for stable, high-performing PSCs based on electron selective monolayers.Peer reviewe

Effect of Carbonization Behaviour of Cotton Biomass in Electrodes for Sodium‐Ion Batteries

Abstract Invited for this issue's Front Cover is the Electromaterials group at the Institute of Frontier Materials of Deakin University (Australia). The cover picture emphasizes the environmental sustainability of recycling cotton textiles to produce flexible & free‐standing hard carbon anodes for sodium‐ion batteries. Read the full text of the Research Article at 10.1002/celc.202300127

Effect of Carbonization Behaviour of Cotton Biomass in Electrodes for Sodium‐Ion Batteries

Abstract Free‐standing hard carbon electrodes are produced from cotton biomass using a low‐cost, one‐step pathway. The free‐standing feature of the electrode eliminates the use of binders and toxic solvents. The electrochemical performance of the electrodes is tested to study the correlation between Na storage and the structural properties of the hard carbon material. A remarkable specific capacity of 272 mAh g−1 at a current density of 50 mA g−1 is obtained with a high initial Coulombic efficiency of 75 % for the cotton fabric (CF) sample pyrolyzed at 1000 °C for 5 min (CF5 min). The excellent performance of the free‐standing electrode is attributed to a large interlayer spacing between the graphene layers, and a high number of oxygen‐containing functional groups on the surface. X‐ray photoelectron spectroscopy (XPS) surface characterisation shows that a thin and uniformly distributed SEI (solid electrolyte interphase) layer, mainly composed of NaF and Na2O, is formed on the CF5 min surface, whereas a thick SEI layer with a long Na+ diffusion pathway is formed on the sample pyrolyzed at 1000 °C for 10 h (CF10 h), which leads to slower reaction kinetics and poor electrochemical performance. This work proposes a scalable and economically feasible strategy to produce sodium ion anode materials with a focus on environmental sustainability and value addition to waste streams

High-Performance Magnesium Electrochemical Cycling with Hybrid Mg-Li Electrolytes

Kinetics and coulombic efficiency of the electrochemical magnesium plating and stripping processes are to a significant extent defined by the composition of the electrolyte solution, optimization of which presents a pathway for improved performance. Adopting this strategy, we undertook a systematic investigation of the Mg0/2+ process in different combinations of the Mg2+-Li+-borohydride-bis(trifluoromethylsulfonyl)imide (TFSI-) electrolytes in 1,2-dimethoxyethane (DME) solvent. Results indicate that the presence of BH4- is essential for high coulombic efficiency, which coordination to Mg2+ was confirmed by Raman and NMR spectroscopic analysis. However, the high rates observed also require the presence of Li+ and a supplementary anion such as TFSI-. The Li+ + BH4- + TFSI- combination of ionic species prevents passivation of the magnesium surface and thereby enables efficient Mg0/2+ electrochemical cycling. The best Mg0/2+ performance with the stabilized coulombic efficiency of 88 ± 1% and one of the highest deposition/stripping rates at ambient temperature reported to date are demonstrated at an optimal [Mg(BH4)2]:[LiTFSI] mole ratio of 1:2.</p

An additively manufactured magnesium-aluminium alloy withstands seawater corrosion

AbstractMagnesium, the lightest structural metal, has inherently poor corrosion resistance. In this study, we developed a magnesium-aluminium Mg-10.6Al-0.6Zn-0.3Mn alloy, additively manufactured by laser powder bed fusion. We reveal that this alloy has a record low degradation rate amongst all magnesium alloys in practically relevant corrosive solutions, and it even withstands seawater corrosion. As tested by a number of methods, the alloy shows even more enhanced passivation with longer immersion periods. The alloy surface following immersion maintained a nearly corrosion-free appearance and was determined to have a thin aluminium-containing surface film, due to surface enrichment of aluminium from the supersaturated matrix. Aluminium enrichment near the sample surface was also observed when the sample is immersed in phosphoric acid or exposed to atmosphere at room temperature. This study demonstrates the prospects for additively manufactured ultra-lightweight magnesium structure with outstanding corrosion resistance.</jats:p