Recent Submissions

  • Translational Molecular Ecology in practice: Linking DNA-based methods to actionable marine environmental management

    Aylagas, Eva; Aylagas, Eva; Pochon, Xavier; Zaiko, Anastasija; Keeley, Nigel; Bruce, Kat; Hong, Pei-Ying; Ruiz, Gregory M.; Stein, Eric D.; Theroux, Susanna; Geraldi, Nathan; Ortega, Alejandra; Gajdzik, Laura; Coker, Darren James; Katan, Yasser; Hikmawan, Tyas; Saleem, Ammar; Alamer, Sultan; Jones, Burton; Duarte, Carlos M.; Pearman, John; Carvalho, Susana (Science of The Total Environment, Elsevier BV, 2020-07-12) [Article]
    Molecular-based approaches can provide timely biodiversity assessments, showing an immense potential to facilitate decision-making in marine environmental management. However, the uptake of molecular data into environmental policy remains minimal. Here, we showcase a selection of local to global scale studies applying molecular-based methodologies for environmental management at various stages of implementation. Drawing upon lessons learned from these case-studies, we provide a roadmap to facilitate applications of DNA-based methods to marine policies and to overcome the existing challenges. The main impediment identified is the need for standardized protocols to guarantee data comparison across spatial and temporal scales. Adoption of Translational Molecular Ecology – the sustained collaboration between molecular ecologists and stakeholders, will enhance consensus with regards to the objectives, methods, and outcomes of environmental management projects. Establishing a sustained dialogue among stakeholders is the key to accelerating the adoption of molecular-based approaches for marine monitoring and assessment.
  • Defect Passivation in Perovskite Solar Cells by Cyano-Based π-Conjugated Molecules for Improved Performance and Stability

    Wang, Kai; Liu, Jiang; Yin, Jun; Aydin, Erkan; Harrison, George T.; Liu, Wenzhu; Chen, Shanyong; Mohammed, Omar F.; De Wolf, Stefaan (Advanced Functional Materials, Wiley, 2020-07-09) [Article]
    Defects at the surface and grain boundaries of metal–halide perovskite films lead to performance losses of perovskite solar cells (PSCs). Here, organic cyano-based π-conjugated molecules composed of indacenodithieno[3,2-b]thiophene (IDTT) are reported and it is found that their cyano group can effectively passivate such defects. To achieve a homogeneous distribution, these molecules are dissolved in the antisolvent, used to initiate the perovskite crystallization. It is found that these molecules are self-anchored at the grain boundaries due to their strong binding to undercoordinated Pb2+. On a device level, this passivation scheme enhances the charge separation and transport at the grain boundaries due to the well-matched energetic levels between the passivant and the perovskite. Consequently, these benefits contribute directly to the achievement of power conversion efficiencies as high as 21.2%, as well as the improved environmental and thermal stability of the PSCs. The surface treatment provides a new strategy to simultaneously passivate defects and enhance charge extraction/transport at the device interface by manipulating the anchoring groups of the molecules.
  • Topology Meets Reticular Chemistry for Chemical Separations: MOFs as a Case Study

    Bhatt, Prashant; Guillerm, Vincent; Datta, Shuvo Jit; Shkurenko, Aleksander; Eddaoudi, Mohamed (Chem, Elsevier BV, 2020-07-09) [Article]
    Chemical separations are of prime industrial importance; however, they consume a large portion of total industrial energy. Credibly, adsorbent-based separation methods offer the prospective to drastically lessen the energy demand of conventional energy-intensive separation processes. Prominently, a special class of porous materials, namely metal-organic frameworks (MOFs), are reasonably positioned to address various demanding separations in an energy-efficient manner. Out of a myriad of possible topologies for the construction of MOFs, face-transitive nets affording a sole type of window, preferably defined by three- or four-membered rings, can be regarded as ideal blueprints for the construction of MOFs for targeted separations. Intricate separations by MOFs based on some of these topologies are discussed, highlighting the effect of appropriate pore aperture and channel size with prerequisite functional groups on their separation performance. MOFs based on face-transitive nets offer great potential as effective fillers for the construction of practical mixed-matrix membranes (MMMs) with improved separation properties over conventional polymeric membranes.
  • Physical and economical evaluation of laboratory-scale membrane bioreactor by long-term relative cost–benefit analysis

    Ayub, Mariam; Saeed, Nadeeha; Chung, Shinho; Nawaz, Muhammad Saqib; Ghaffour, NorEddine (Journal of Water Reuse and Desalination, IWA Publishing, 2020-07-08) [Article]
    Two laboratory-scale single-stage submerged membrane bioreactors (MBRs) were operated in parallel to examine the effect of different flux conditions and several fouling mitigation methods. After control operation (filtration only), three fouling control methods (relaxation, standard backwash and chemical backwash) at 27 LMH flux and four different flux conditions (54, 36, 27 and 18 LMH) with standard backwash were applied. Physical performance of MBRs was evaluated based on the operational duration to reach maximum transmembrane pressure and the volume of permeate produced during the operational duration. Then relative cost–benefit analysis was carried out. Results showed that the combination of chemical backwash and standard backwash was the most effective for fouling mitigation in terms of physical improvement of MBR performance. However, the combination proved less economical (400% + α relative cost) than standard backwash alone (343% relative cost), because of the additional cost for pumps and chemical. It also showed that lower flux (18 LMH) is desirable as it showed better physical performance (1,770% improvement as compared to the highest flux, 54 LMH) and proved more economical than higher flux configuration. Therefore, it is concluded that the operation with standard backwash at the lowest possible flux is the best combination to improve MBR performance as well as long-term cost–benefit.
  • Natal philopatry increases relatedness within groups of coral reef cardinalfish

    Rueger, Theresa; Harrison, Hugo B.; Buston, Peter M.; Gardiner, Naomi M.; Berumen, Michael L.; Jones, G. P. (Proceedings of the Royal Society B: Biological Sciences, The Royal Society, 2020-07-08) [Article]
    A central issue in evolutionary ecology is how patterns of dispersal influence patterns of relatedness in populations. In terrestrial organisms, limited dispersal of offspring leads to groups of related individuals. By contrast, for most marine organisms, larval dispersal in open waters is thought to minimize kin associations within populations. However, recent molecular evidence and theoretical approaches have shown that limited dispersal, sibling cohesion and/or differential reproductive success can lead to kin association and elevated relatedness. Here, we tested the hypothesis that limited dispersal explains small-scale patterns of relatedness in the pajama cardinalfish Sphaeramia nematoptera. We used 19 microsatellite markers to assess parentage of 233 juveniles and pairwise relatedness among 527 individuals from 41 groups in Kimbe Bay, Papua New Guinea. Our findings support three predictions of the limited dispersal hypothesis: (i) elevated relatedness within groups, compared with among groups and elevated relatedness within reefs compared with among reefs; (ii) a weak negative correlation of relatedness with distance; (iii) more juveniles than would be expected by chance in the same group and the same reef as their parents. We provide the first example for natal philopatry at the group level causing small-scale patterns of genetic relatedness in a marine fish.
  • Chemoselective Hydrogenation of Alkynes to (Z)-Alkenes Using an Air-Stable Base Metal Catalyst

    Zubar, Viktoriia; Sklyaruk, Jan; Brzozowska, Aleksandra; Rueping, Magnus (Organic Letters, American Chemical Society (ACS), 2020-07-08) [Article]
    A highly selective hydrogenation of alkynes using an air-stable and readily available manganese catalyst has been achieved. The reaction proceeds under mild reaction conditions and tolerates various functional groups, resulting in (Z)-alkenes and allylic alcohols in high yields. Mechanistic experiments suggest that the reaction proceeds via a bifunctional activation involving metal–ligand cooperativity.
  • Draft Genome Sequences of Three Bacillus Species Isolated from Biofouled Reverse-Osmosis Membranes

    Rehman, Zahid Ur; Iftikhar, Muhammad Ali; Leiknes, TorOve (Microbiology Resource Announcements, American Society for Microbiology, 2020-07-08) [Article]
    <jats:title>ABSTRACT</jats:title> <jats:p>Here, we present the draft genome sequences of three bacteria belonging to the genus <jats:italic>Bacillus</jats:italic> which were isolated from biofouled reverse-osmosis (RO) membranes harvested from a full-scale desalination plant. The sizes of the assembled genomes for RO1, RO2, and RO3 were 4.22 Mb, 4.15 Mb, and 4.23 Mb, respectively.</jats:p>
  • Seagrass losses since mid-20th century fuelled CO 2 emissions from soil carbon stocks

    Salinas, Cristian; Duarte, Carlos M.; Lavery, P. S.; Masqué, Pere; Arias-Ortiz, Ariane; Leon, Javier X.; Callaghan, David; Kendrick, G. A.; Serrano, Oscar (Global Change Biology, Wiley, 2020-07-07) [Article]
    Seagrass meadows store globally significant organic carbon (Corg) stocks which, if disturbed, can lead to CO2 emissions, contributing to climate change. Eutrophication and thermal stress continue to be a major cause of seagrass decline worldwide, but the associated CO2 emissions remain poorly understood. This study presents comprehensive estimates of seagrass soil Corg erosion following eutrophication-driven seagrass loss in Cockburn Sound (23 km2 between 1960s and 1990s) and identifies the main drivers. We estimate that shallow seagrass meadows (<5 m depth) had significantly higher Corg stocks in 50 cm thick soils (4.5 ± 0.7 kg Corg/m2) than previously vegetated counterparts (0.5 ± 0.1 kg Corg/m2). In deeper areas (>5 m), however, soil Corg stocks in seagrass and bare but previously vegetated areas were not significantly different (2.6 ± 0.3 and 3.0 ± 0.6 kg Corg/m2, respectively). The soil Corg sequestration capacity prevailed in shallow and deep vegetated areas (55 ± 11 and 21 ± 7 g Corg m−2 year−1, respectively), but was lost in bare areas. We identified that seagrass canopy loss alone does not necessarily drive changes in soil Corg but, when combined with high hydrodynamic energy, significant erosion occurred. Our estimates point at ~0.20 m/s as the critical shear velocity threshold causing soil Corg erosion. We estimate, from field studies and satellite imagery, that soil Corg erosion (within the top 50 cm) following seagrass loss likely resulted in cumulative emissions of 0.06–0.14 Tg CO2-eq over the last 40 years in Cockburn Sound. We estimated that indirect impacts (i.e. eutrophication, thermal stress and light stress) causing the loss of ~161,150 ha of seagrasses in Australia, likely resulted in the release of 11–21 Tg CO2-eq since the 1950s, increasing cumulative CO2 emissions from land-use change in Australia by 1.1%–2.3% per annum. The patterns described serve as a baseline to estimate potential CO2 emissions following disturbance of seagrass meadows.
  • SARS-CoV-2 infections and COVID-19 mortalities strongly correlate with ACE1 I/D genotype.

    Yamamoto, Naoki; Ariumi, Yasuo; Nishida, Nao; Yamamoto, Rain; Bauer, Georg; Gojobori, Takashi; Shimotohno, Kunitada; Mizokami, Masashi (Gene, Elsevier BV, 2020-07-07) [Article]
    Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). The relentless spread and pathogenicity of the virus have become a global public health emergency. One of the striking features of this pandemic is the pronounced impact on specific regions and ethnic groups. In particular, compared with East Asia, where the virus first emerged, SARS-CoV-2 has caused high rates of morbidity and mortality in Europe. This has not been experienced in past global viral infections, such as influenza, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) and is unique to SARS-CoV-2. For this reason, we investigated the involvement of genetic factors associated with SARS-CoV-2 infection with a focus on angiotensin-converting enzyme (ACE)-related genes, because ACE2 is a receptor for SARS-CoV-2. We found that the ACE1 II genotype frequency in a population was significantly negatively correlated with the number of SARS-CoV-2 cases. Similarly, the ACE1 II genotype was negatively correlated with the number of deaths due to SARS-CoV-2 infection. These data suggest that the ACE1 II genotype may influence the prevalence and clinical outcome of COVID-19 and serve as a predictive marker for COVID-19 risk and severity.
  • Systematic Study on Morphological Development of Blade-Coated Conjugated Polymer Thin Films via In Situ Measurements

    Kim, Yeon-Ju; Lee, Sehyun; Niazi, Muhammad Rizwan; Hwang, Kyoungtae; Tang, Ming-Chun; Lim, Dae-Hee; Kang, Ji-Sue; Smilgies, Detlef-M.; Amassian, Aram; Kim, Dong-Yu (ACS Applied Materials & Interfaces, American Chemical Society (ACS), 2020-07-07) [Article]
    The morphology of conjugated polymer thin films, determined by the kinetics of film drying, is closely correlated with their electrical properties. Herein, we focused on dramatic changes in thin film morphology of blade-coated poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} caused by the effect of solvent and coating temperature. Through in situ measurements the evolution of polymer aggregates and crystallites, which plays a decisive role in the formation of the charge transporting pathway, was observed in real-time. By combining in situ ultraviolet-visible spectroscopy and in situ grazing-incidence wide-angle X-ray scattering analysis, we could identify five distinct stages during the blade-coating process; these stages were observed irrespective of the solvent and coating temperature used. The five stages are described in detail with a proposed model of film formation. This insight is an important step in understanding the relationship between the morphology of thin polymer films and their charge-transport properties as well as optimizing the structural evolution of thin films.
  • Expression of a carotenogenic gene allows faster biomass production by redesigning plant architecture and improving photosynthetic efficiency in tobacco.

    Moreno, Juan C; Mi, Jianing; Agrawal, Shreya; Kössler, Stella; Turečková, Veronika; Tarkowská, Danuše; Thiele, Wolfram; Al-Babili, Salim; Bock, Ralph; Schöttler, Mark Aurel (The Plant journal : for cell and molecular biology, Wiley, 2020-07-06) [Article]
    Because carotenoids act as accessory pigments in photosynthesis, play a key photoprotective role, and are of major nutritional importance, carotenogenesis has been a target for crop improvement. Although carotenoids are important precursors of phytohormones, previous genetic manipulations reported little if any effects on biomass production and plant development, but resulted in specific modifications in carotenoid content. Unexpectedly, the expression of the carrot lycopene b-cyclase (DcLCYB1) in Nicotiana tabacum cv. Xanthi not only resulted in increased carotenoid accumulation, but also in altered plant architecture characterized by longer internodes, faster plant growth, early flowering and increased biomass. Here, we have challenged these transformants with a range of growth conditions to determine the robustness of their phenotype and analyze the underlying mechanisms. Transgenic DcLCYB1 lines showed increased transcript levels of key genes involved in carotenoid, chlorophyll, gibberellin (GA) and abscisic acid (ABA) biosynthesis, but also in photosynthesis-related genes. Accordingly, their carotenoid, chlorophyll, ABA and GA contents were increased. Hormone application and inhibitor experiments confirmed the key role of altered GA/ABA contents in the growth phenotype. Because the longer internodes reduce shading of mature leaves, induction of leaf senescence was delayed, and mature leaves maintained a high photosynthetic capacity. This increased total plant assimilation, as reflected in higher plant yields under both fully-controlled constant and fluctuating light, and in non-controlled conditions. Furthermore, our data is a warning that engineering of isoprenoid metabolism can cause complex changes in phytohormone homeostasis and therefore plant development, which have not been sufficiently considered in previous studies.
  • Unfamiliar partnerships limit cnidarian holobiont acclimation to warming

    Herrera Sarrias, Marcela; Klein, Shannon; Schmidt-Roach, Sebastian; Campana, Sara; Cziesielski, Maha Joana; Chen, Jit Ern; Duarte, Carlos M.; Aranda, Manuel (Global Change Biology, Wiley, 2020-07-06) [Article]
    Enhancing the resilience of corals to rising temperatures is now a matter of urgency, leading to growing efforts to explore the use of heat tolerant symbiont species to improve their thermal resilience. The notion that adaptive traits can be retained by transferring the symbionts alone, however, challenges the holobiont concept, a fundamental paradigm in coral research. Holobiont traits are products of a specific community (holobiont) and all its co-evolutionary and local adaptations, which might limit the retention or transference of holobiont traits by exchanging only one partner. Here, we evaluate how interchanging partners affect the short- and long-term performance of holobionts under heat stress using clonal lineages of the cnidarian model system Aiptasia (host and Symbiodiniaceae strains) originating from distinct thermal environments. Our results show that holobionts from more thermally variable environments have higher plasticity to heat stress, but this resilience could not be transferred to other host genotypes through the exchange of symbionts. Importantly, our findings highlight the role of the host in determining holobiont productivity in response to thermal stress and indicate that local adaptations of holobionts will likely limit the efficacy of interchanging unfamiliar compartments to enhance thermal tolerance.
  • Biofouling control by phosphorus limitation strongly depends on the assimilable organic carbon concentration.

    Javier, Luisa; Farhat, Nadia M; Desmond, Peter; Linares, Rodrigo Valladares; Bucs,Szilard; Kruithof, Joop C; Vrouwenvelder, Johannes S. (Water research, Elsevier BV, 2020-07-05) [Article]
    Nutrient limitation is a biofouling control strategy in reverse osmosis (RO) membrane systems. In seawater, the assimilable organic carbon content available for bacterial growth ranges from about 50 to 400 μg C·L-1, while the phosphorus concentration ranges from 3 to 11 μg P·L-1. Several studies monitored biofouling development, limiting either carbon or phosphorus. The effect of carbon to phosphorus ratio and the restriction of both nutrients on membrane system performance have not yet been investigated. This study examines the impact of reduced phosphorus concentration (from 25 μg P·L-1 and 3 μg P·L-1, to a low concentration of ≤0.3 μg P·L-1), combined with two different carbon concentrations (250 C L-1 and 30 μg C·L-1), on biofilm development in an RO system. Feed channel pressure drop was measured to determine the effect of the developed biofilm on system performance. The morphology of the accumulated biomass for both carbon concentrations was characterized by optical coherence tomography (OCT) and the biomass amount and composition was quantified by measuring total organic carbon (TOC), adenosine triphosphate (ATP), total cell counts (TCC), and extracellular polymeric substances (EPS) concentration for the developed biofilms under phosphorus restricted (P-restricted) and dosed (P-dosed) conditions. For both carbon concentrations, P-restricted conditions (≤0.3 μg P·L-1) limited bacterial growth (lower values of ATP, TCC). A faster pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 250 μg C·L-1 was dosed. This faster pressure drop increase can be explained by a higher area covered by biofilm in the flow channel and a higher amount of produced EPS. Conversely, a slower pressure drop increase was observed for P-restricted conditions compared to P-dosed conditions when 30 μg C·L-1 was dosed. Results of this study demonstrate that P-limitation delayed biofilm formation effectively when combined with low assimilable organic carbon concentration and thereby, lengthening the overall membrane system performance.
  • Effect of organic micropollutants on biofouling in a forward osmosis process integrating seawater desalination and wastewater reclamation

    Kim,Youngjin; Kim, Lan Hee; Vrouwenvelder, Johannes S.; Ghaffour, NorEddine (Journal of Hazardous Materials, Elsevier BV, 2020-07-04) [Article]
    This study systematically investigated the effect of organic micropollutants (OMPs) on biofouling in forward osmosis (FO) integrating wastewater treatment and seawater dilution. Synthetic seawater (0.6 M sodium chloride) was used as a draw solution and synthetic municipal wastewater as a feed solution. To evaluate the impact of OMPs in a replicate parallel study, wastewater was supplemented with a mixture of 7 OMPs (OMPs-feed) and without OMPs (control) during 8 batch filtration cycles with feed and draw solution replacement after each filtration. The FO performance (water flux), development and microbial composition properties of biofilm layers on the wastewater side of the FO membrane were studied. Compared to the control without OMPs, the FO fed with OMPs containing wastewater showed (i) initially the same water flux and flux decline during the first filtration cycle, (ii) with increasing filtration cycle a lower flux decline and (iii) lower concentrations for the total cells, ATP, EPS carbohydrates and proteins in biofilm layers, and (iv) a lower diversity of the biofilm microbial community composition (indicating selective pressure) and (v) increasing rejection of 6 of the 7 OMPs. In essence, biofouling on the FO membrane showed (i) a lower flux decline in the presence of OMPs in the feed water and (ii) a higher OMPs rejection, both illustrating better membrane performance. This study has a significant implication for optimizing osmotic dilution in terms of FO operation and OMPs rejection.
  • Autoignition of diethyl ether and a diethyl ether/ethanol blend

    Issayev, Gani; Sarathy, Mani; Farooq, Aamir (Fuel, Elsevier BV, 2020-07-04) [Article]
    Binary blends of fast-reacting diethyl ether (DEE) and slow-reacting ethanol (EtOH) are quite promising as renewable replacements for conventional fuels in modern compression ignition engines. In this work, pure diethyl ether and a 50/50 M binary blend of diethyl ether and ethanol (DEE/EtOH) were investigated in a shock tube and a rapid compression machine. Ignition delay times were measured over the temperature range of 550–1000 K, pressures of 20–40 bar, and equivalence ratios of 0.5–1. Literature reaction mechanisms of diethyl ether and ethanol were combined to simulate the reactivity trends of the blends. Species rate-of-production and sensitivity analyses were performed to analyze the interplay between radicals originating from the two fuels. Multistage ignition behavior was observed in both experiments and simulations, with peculiar 3-stage ignition visible at fuel-lean conditions. Kinetic analyses were used to identify the reactions controlling various stages of ignition. Reactivity comparison of DEE/EtOH and dimethyl ether/ethanol (DME/EtOH) blends showed that the oxidation of DEE blends is controlled by acetaldehyde whereas formaldehyde controls the oxidation of DME blends.
  • Unrealistic energy and materials requirement for direct air capture in deep mitigation pathways

    Chatterjee, Sudipta; Huang, Kuo-Wei (Nature Communications, Springer Science and Business Media LLC, 2020-07-03) [Article]
    The increasing global atmospheric CO2 concentration due to heavy reliance on fossil fuels as the primary energy sources (~410 ppm in 2019)1 has made direct extraction or removal of CO2 from ambient air (direct air carbon capture (DACC)) the most logical alternative over traditional modes of carbon capture from large stationary sources because of many of the perceived advantages and compelling arguments2. With the current level of CO2 emissions (32.6 gigatons (Gt)-CO2/year2017)1, Realmonte and co-workers recently imposed the global capacity at 30 Gt-CO2/year as a case study for DACC, and concluded that “in theory DACCS can be an enabling factor for the Paris Agreement objectives” and recommended the policy makers to “support an acceleration in development and deployment of DACCS”3. While challenges of large-scale CO2 utilization and sequestration were recognized and these approaches were deemed impractical4,5, our analysis further showed that the energy and materials requirements for DACC are unrealistic even when the most promising technologies are employed. Thus, DACC is unfortunately only an energetically and financially costly distraction in effective mitigation of climate changes at a meaningful scale before we achieve the status of a significant surplus of carbon-neutral/low-carbon energy.
  • Bioconversion of swine manure into high-value products of medium chain fatty acids.

    Zhang, Wanqin; Yin, Fubin; Dong, Hongmin; Cao, Qitao; Wang, Shunli; Xu, Jiajie; Zhu, Zhiping (Waste management (New York, N.Y.), Elsevier BV, 2020-07-03) [Article]
    This research proposes and demonstrates, for the first time, the utilization of swine manure as a complex feedstock to produce high-value medium chain fatty acids (MCFA). The two-stage anaerobic digestion (AD) carboxylates platform was adopted for the conversion of swine manure to short chain fatty acids (SCFAs) and then SCFAs to MCFA (n-caproate, n-heptanoate, and n-caprylate) with ethanol supplementation. We defined the appropriate initial pH of 10.0 for SCFAs production with a carbon conversion rate of 71.2%, and acetate, propionate were the main products, which accounted for around 72.9% of the total SCFAs in the primary stage (I). Through the addition of ethanol, 61.3% of the converted carbon in the complex SCFAs solution was converted into MCFA (C6-C8) in the chain elongation stage (II), while only 6.7% was attributed to methane formation. The concentrations of n-caproate, n-heptanoate, and n-caprylate reached 8.6 g COD/L (3.9 g/L), 6.4 g COD/L (2.7 g/L), and 2.6 g COD/L (1.07 g/L), respectively. This study achieved a relatively higher concentration of n-heptanoate compared with past studies of MCFA from other feedstock. These findings demonstrated a new route for resource recovery and the operating parameters for producing MCFA from swine manure.
  • A Highly Conductive Titanium Oxynitride Electron-Selective Contact for Efficient Photovoltaic Devices.

    Yang, Xinbo; Lin, Yuanbao; Liu, Jiang; Liu, Wenzhu; Bi, Qunyu; Song, Xin; Kang, Jingxuan; Xu, Fuzong; Xu, Lujia; Hedhili, Mohamed N.; Baran, Derya; Zhang, Xiaohong; Anthopoulos, Thomas D.; De Wolf, Stefaan (Advanced materials (Deerfield Beach, Fla.), Wiley, 2020-07-03) [Article]
    High-quality carrier-selective contacts with suitable electronic properties are a prerequisite for photovoltaic devices with high power conversion efficiency (PCE). In this work, an efficient electron-selective contact, titanium oxynitride (TiOx Ny ), is developed for crystalline silicon (c-Si) and organic photovoltaic devices. Atomic-layer-deposited TiOx Ny is demonstrated to be highly conductive with a proper work function (4.3 eV) and a wide bandgap (3.4 eV). Thin TiOx Ny films simultaneously provide a moderate surface passivation and enable a low contact resistivity on c-Si surfaces. By implementation of an optimal TiOx Ny -based contact, a state-of-the-art PCE of 22.3% is achieved for a c-Si solar cell featuring a full-area dopant-free electron-selective contact. Simultaneously, conductive TiOx Ny is proven to be an efficient electron-transport layer for organic photovoltaic (OPV) devices. A remarkably high PCE of 17.02% is achieved for an OPV device with an electron-transport TiOx Ny layer, which is superior to conventional ZnO-based devices with a PCE of 16.10%. Atomic-layer-deposited TiOx Ny ETL on a large area with a high uniformity may help accelerate the commercialization of emerging solar technologies.
  • Temperature-resilient solid-state organic artificial synapses for neuromorphic computing

    Melianas, Armantas; Quill, T. J.; LeCroy, G.; Tuchman, Y.; Loo, H. v.; Keene, S. T.; Giovannitti, Alexander; Lee, H. R.; Maria, I. P.; McCulloch, Iain; Salleo, Alberto (Science Advances, American Association for the Advancement of Science (AAAS), 2020-07-03) [Article]
    <jats:p>Devices with tunable resistance are highly sought after for neuromorphic computing. Conventional resistive memories, however, suffer from nonlinear and asymmetric resistance tuning and excessive write noise, degrading artificial neural network (ANN) accelerator performance. Emerging electrochemical random-access memories (ECRAMs) display write linearity, which enables substantially faster ANN training by array programing in parallel. However, state-of-the-art ECRAMs have not yet demonstrated stable and efficient operation at temperatures required for packaged electronic devices (~90°C). Here, we show that (semi)conducting polymers combined with ion gel electrolyte films enable solid-state ECRAMs with stable and nearly temperature-independent operation up to 90°C. These ECRAMs show linear resistance tuning over a >2× dynamic range, 20-nanosecond switching, submicrosecond write-read cycling, low noise, and low-voltage (±1 volt) and low-energy (~80 femtojoules per write) operation combined with excellent endurance (>10$^\{9}$$ write-read operations at 90°C). Demonstration of these high-performance ECRAMs is a fundamental step toward their implementation in hardware ANNs.</jats:p>
  • Early-Stage Growth Mechanism and Synthesis Conditions-Dependent Morphology of Nanocrystalline Bi Films Electrodeposited from Perchlorate Electrolyte.

    Tishkevich, Daria; Grabchikov, Sergey; Zubar, Tatiana; Vasin, Denis; Trukhanov, Sergei; Vorobjova, Alla; Yakimchuk, Dmitry; Kozlovskiy, Artem; Zdorovets, Maxim; Giniyatova, Sholpan; Shimanovich, Dmitriy; Lyakhov, Dmitry; Michels, Dominik L.; Dong, Mengge; Gudkova, Svetlana; Trukhanov, Alex (Nanomaterials (Basel, Switzerland), MDPI AG, 2020-07-02) [Article]
    Bi nanocrystalline films were formed from perchlorate electrolyte (PE) on Cu substrate via electrochemical deposition with different duration and current densities. The microstructural, morphological properties, and elemental composition were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray microanalysis (EDX). The optimal range of current densities for Bi electrodeposition in PE using polarization measurements was demonstrated. For the first time, it was shown and explained why, with a deposition duration of 1 s, co-deposition of Pb and Bi occurs. The correlation between synthesis conditions and chemical composition and microstructure for Bi films was discussed. The analysis of the microstructure evolution revealed the changing mechanism of the films' growth from pillar-like (for Pb-rich phase) to layered granular form (for Bi) with deposition duration rising. This abnormal behavior is explained by the appearance of a strong Bi growth texture and coalescence effects. The investigations of porosity showed that Bi films have a closely-packed microstructure. The main stages and the growth mechanism of Bi films in the galvanostatic regime in PE with a deposition duration of 1-30 s are proposed.

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