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Showing papers on "Atomic layer deposition published in 2017"


Journal ArticleDOI
TL;DR: In this paper, the authors improved the efficiency of monolithic, two-terminal, 1-cm2 perovskite/silicon tandems to 23.6% by combining an infrared-tuned silicon heterojunction bottom cell with the recently developed caesium formamidinium lead halide pervskite.
Abstract: As the record single-junction efficiencies of perovskite solar cells now rival those of copper indium gallium selenide, cadmium telluride and multicrystalline silicon, they are becoming increasingly attractive for use in tandem solar cells due to their wide, tunable bandgap and solution processability. Previously, perovskite/silicon tandems were limited by significant parasitic absorption and poor environmental stability. Here, we improve the efficiency of monolithic, two-terminal, 1-cm2 perovskite/silicon tandems to 23.6% by combining an infrared-tuned silicon heterojunction bottom cell with the recently developed caesium formamidinium lead halide perovskite. This more-stable perovskite tolerates deposition of a tin oxide buffer layer via atomic layer deposition that prevents shunts, has negligible parasitic absorption, and allows for the sputter deposition of a transparent top electrode. Furthermore, the window layer doubles as a diffusion barrier, increasing the thermal and environmental stability to enable perovskite devices that withstand a 1,000-hour damp heat test at 85 ∘C and 85% relative humidity. Perovskite solar cells can complement silicon photovoltaics in multijunction devices. Here, the authors optimize light harvesting in monolithic perovskite-on-silicon devices and fabricate a certified 23.6% efficient, 1 cm2 tandem solar cell with a perovskite device that withstands damp heat tests.

1,163 citations


Journal ArticleDOI
TL;DR: Pt2 dimers can be fabricated with a bottom–up approach on graphene using atomic layer deposition, through proper nucleation sites creation, Pt1 single-atom deposition and attaching a secondary Pt atom selectively on the preliminary one.
Abstract: Supported metal clusters containing only a few atoms are of great interest. Progress has been made in synthesis of metal single-atom catalysts. However, precise synthesis of metal dimers on high-surface area support remains a grand challenge. Here, we show that Pt2 dimers can be fabricated with a bottom–up approach on graphene using atomic layer deposition, through proper nucleation sites creation, Pt1 single-atom deposition and attaching a secondary Pt atom selectively on the preliminary one. Scanning transmission electron microscopy, x-ray absorption spectroscopy, and theoretical calculations suggest that the Pt2 dimers are likely in the oxidized form of Pt2Ox. In hydrolytic dehydrogenation of ammonia borane, Pt2 dimers exhibit a high specific rate of 2800 molH2 molPt −1 min−1 at room temperature, ~17- and 45-fold higher than graphene supported Pt single atoms and nanoparticles, respectively. These findings open an avenue to bottom–up fabrication of supported atomically precise ultrafine metal clusters for practical applications. Controlled fabrication of few-atoms supported catalysts is a major challenge in the synthesis of nanomaterials. Here, the authors show a bottom-up approach to precisely synthesize platinum dimers supported on graphene, which display higher catalytic activity and stability than single atoms and nanoparticles.

645 citations


Journal ArticleDOI
TL;DR: Schreier et al. as discussed by the authors introduced atomic layer deposition of SnO2 on CuO nanowires as a means for changing the wide product distribution of CuO-derived CO2 reduction electrocatalysts to yield predominantly CO.
Abstract: The solar-driven electrochemical reduction of CO2 to fuels and chemicals provides a promising way for closing the anthropogenic carbon cycle. However, the lack of selective and Earth-abundant catalysts able to achieve the desired transformation reactions in an aqueous matrix presents a substantial impediment as of today. Here we introduce atomic layer deposition of SnO2 on CuO nanowires as a means for changing the wide product distribution of CuO-derived CO2 reduction electrocatalysts to yield predominantly CO. The activity of this catalyst towards oxygen evolution enables us to use it both as the cathode and anode for complete CO2 electrolysis. In the resulting device, the electrodes are separated by a bipolar membrane, allowing each half-reaction to run in its optimal electrolyte environment. Using a GaInP/GaInAs/Ge photovoltaic we achieve the solar-driven splitting of CO2 into CO and oxygen with a bifunctional, sustainable and all Earth-abundant system at an efficiency of 13.4%. Electrochemical reduction of CO2 to CO is a route to synthesize fuels, but cheaper and more selective catalysts are required. Using a cell equipped with a bipolar membrane and the same Earth-abundant electrocatalyst at each electrode, Schreier et al. selectively produce CO, powered by a triple-junction photovoltaic.

384 citations


Journal ArticleDOI
TL;DR: In this paper, a composite SnO2/MXene anode was fabricated for Li-ion battery applications, where conductive MXene sheets act to buffer the volume changes associated with lithiation and delithiation.

383 citations


Journal ArticleDOI
TL;DR: The assembly of CsPbBr3 QD/AlOx inorganic nanocomposites, by using atomic layer deposition (ALD) for the growth of the amorphous alumina matrix (AlOx), is described as a novel protection scheme for such QDs.
Abstract: Herein, the assembly of CsPbBr3 QD/AlOx inorganic nanocomposite, using atomic layer deposition (ALD) for the growth of the amorphous alumina matrix (AlOx), is proven as a novel protection scheme for this new class of QDs. The nucleation and growth process of AlOx on the QD surface was thoroughly investigated by a miscellanea of techniques which highlighed the importance of the interaction between the ALD precursor and the QD surface to uniformely coat the QDs while preserving the optoelectronic properties. These nanocomposites show an exceptional stability against exposure to air (for at least 45 days), irradiation under simulated solar spectrum (for at least 8h), to thermal treatment (at least up to 200oC in air), and finally against immersion in water. The method was extended to assembly CsPbBrxI3-x QD/AlOx and CsPbI3 QD/AlOx nanocomposites which were more stable compared to the pristine QD films.

362 citations


Journal ArticleDOI
TL;DR: A new CoOx /TiO2 /Pt photocatalyst produced by template-assisted atomic layer deposition is reported for photocatalytic hydrogen production on Pt and CoOx dual cocatalysts.
Abstract: Efficient separation of photogenerated electrons and holes, and associated surface reactions, is a crucial aspect of efficient semiconductor photocatalytic systems employed for photocatalytic hydrogen production. A new CoOx/TiO2/Pt photocatalyst produced by template-assisted atomic layer deposition is reported for photocatalytic hydrogen production on Pt and CoOx dual cocatalysts. Pt nanoclusters acting as electron collectors and active sites for the reduction reaction are deposited on the inner surface of porous TiO2 nanotubes, while CoOx nanoclusters acting as hole collectors and active sites for oxidation reaction are deposited on the outer surface of porous TiO2 nanotubes. A CoOx/TiO2/Pt photocatalyst, comprising ultra-low concentrations of noble Pt (0.046 wt %) and CoOx (0.019 wt %) deposited simultaneously with one atomic layer deposition cycle, achieves remarkably high photocatalytic efficiency (275.9 μmol h−1), which is nearly five times as high as that of pristine TiO2 nanotubes (56.5 μmol h−1). The highly dispersed Pt and CoOx nanoclusters, porous structure of TiO2 nanotubes with large specific surface area, and the synergetic effect of the spatially separated Pt and CoOx dual cocatalysts contribute to the excellent photocatalytic activity.

272 citations


Journal ArticleDOI
TL;DR: By protecting Na foil with ultrathin Al2 O3 layer, the dendrites and mossy Na formation have been effectively suppressed and lifetime has been significantly improved, and the novel design of atomic layer deposition protected metal Na anode may bring in new opportunities to the realization of the next-generation high energy-density Na metal batteries.
Abstract: Na-metal batteries are considered as the promising alternative candidate for Li-ion battery beneficial from the wide availability and low cost of sodium, high theoretical specific capacity, and high energy density based on the plating/stripping processes and lowest electrochemical potential. For Na-metal batteries, the crucial problem on metallic Na is one of the biggest challenges. Mossy or dendritic growth of Na occurs in the repetitive Na stripping/plating process with an unstable solid electrolyte interphase layer of nonuniform ionic flux, which can not only lead to the low Coulombic efficiency, but also can create short circuit risks, resulting in possible burning or explosion. In this communication, the atomic layer deposition of Al2O3 coating is first demonstrated for the protection of metallic Na anode for Na-metal batteries. By protecting Na foil with ultrathin Al2O3 layer, the dendrites and mossy Na formation have been effectively suppressed and lifetime has been significantly improved. Furthermore, the thickness of protective layer has been further optimized with 25 cycles of Al2O3 layer presenting the best performance over 500 cycles. The novel design of atomic layer deposition protected metal Na anode may bring in new opportunities to the realization of the next-generation high energy-density Na metal batteries.

260 citations


Journal ArticleDOI
TL;DR: The chemically and mechanically stable hybrid LiF/h-BN film successfully suppresses lithium dendrite formation during both the initial electrochemical deposition onto a copper foil and the subsequent cycling.
Abstract: Defects are important features in two-dimensional (2D) materials that have a strong influence on their chemical and physical properties. Through the enhanced chemical reactivity at defect sites (point defects, line defects, etc.), one can selectively functionalize 2D materials via chemical reactions and thereby tune their physical properties. We demonstrate the selective atomic layer deposition of LiF on defect sites of h-BN prepared by chemical vapor deposition. The LiF deposits primarily on the line and point defects of h-BN, thereby creating seams that hold the h-BN crystallites together. The chemically and mechanically stable hybrid LiF/h-BN film successfully suppresses lithium dendrite formation during both the initial electrochemical deposition onto a copper foil and the subsequent cycling. The protected lithium electrodes exhibit good cycling behavior with more than 300 cycles at relatively high coulombic efficiency (>95%) in an additive-free carbonate electrolyte.

230 citations


Journal ArticleDOI
TL;DR: In this paper, the photocatalytic properties of ZnO synthesized in several forms were reported, such as the formation of 3-nm thin films by ALD, electrospinnig, and chemical bath deposition.

211 citations


Journal ArticleDOI
TL;DR: In this paper, an ultra-thin ALD Al2O3 film was used to conformally deposit the material on top of the perovskite absorber to provide a tunnel contact.
Abstract: Perovskite materials are drawing tremendous interest for photovoltaic solar cell applications, but are hampered by intrinsic material and device instability issues. Such issues can arise from environmental influences as well as from the chemical incompatibility of the perovskite layer with charge transport layers and electrodes used in the device stack. Several attempts have been made to address the instability issue, mostly concentrating on the substitution of the organic cations in the perovskite lattice, and on alternatives for the organic charge extraction layers, without laying much emphasis on stabilising the existing, conventional high efficiency methylammonium lead iodide/spiro-OMeTAD based devices. To address the latter issue, we utilized atomic layer deposition (ALD) as a straightforward and soft deposition process to conformally deposit Al2O3 on top of the perovskite absorber. An ultra-thin ALD Al2O3 film effectively protects the perovskite layer while it is sufficiently thin enough to provide a tunnel contact. The fabricated perovskite solar cells (PSCs) exhibit superior device performance with a stabilised power conversion efficiency (PCE) of 18%, a significant reduction in hysteresis loss, and enhanced long-term stability (beyond 60 days) as a function of the unencapsulated storage time in ambient air, under humidity conditions ranging from 40 to 70% at room temperature. PCE measurements after 70 days of humidity exposure show that the devices incorporating 10 cycles of ALD Al2O3 could significantly retard the humidity-induced degradation thereby retaining about 60–70% of its initial PCE, while that of the reference devices drops to a remaining 12% of their initial PCE. This work successfully addresses and tackles the problem of the hybrid organic–inorganic IV-halide perovskite solar cell’s instability in a humid environment, and the key findings pave the way to the upscaling of these devices.

211 citations


Journal ArticleDOI
TL;DR: In this paper, a conformal, ultrathin, amorphous TiO2 film deposited by low-temperature atomic layer deposition (ALD) on top of b-Si can simultaneously address both charge recombination and low electrochemical stability.
Abstract: Black silicon (b-Si) is a surface-nanostructured Si with extremely efficient light absorption capability and is therefore of interest for solar energy conversion. However, intense charge recombination and low electrochemical stability limit the use of b-Si in photoelectrochemical solar-fuel production. Here we report that a conformal, ultrathin, amorphous TiO2 film deposited by low-temperature atomic layer deposition (ALD) on top of b-Si can simultaneously address both of these issues. Combined with a Co(OH)2 thin film as the oxygen evolution catalyst, this b-Si/TiO2/Co(OH)2 heterostructured photoanode was able to produce a saturated photocurrent density of 32.3 mA cm−2 at an external potential of 1.48 V versus reversible reference electrode (RHE) in 1 M NaOH electrolyte. The enhanced photocurrent relative to planar Si and unprotected b-Si photoelectrodes was attributed to the enhanced charge separation efficiency as a result of the effective passivation of defective sites on the b-Si surface. The 8-nm ALD TiO2 layer extends the operational lifetime of b-Si from less than half an hour to four hours. Nanostructured black silicon can be used as a photoelectrode for solar-driven water splitting, but its high surface area can increase charge recombination and accelerate corrosion. Here the authors show that a thin, conformal film of TiO2 can increase both the photocurrent and the stability of black silicon.

Journal ArticleDOI
TL;DR: By protecting Na anode with controllable alucone layer, the dendrites and mossy Na formation have been effectively suppressed and the lifetime has been significantly improved.
Abstract: Metallic Na anode is considered as a promising alternative candidate for Na ion batteries (NIBs) and Na metal batteries (NMBs) due to its high specific capacity, and low potential. However, the unstable solid electrolyte interphase layer caused by serious corrosion and reaction in electrolyte will lead to big challenges, including dendrite growth, low Coulombic efficiency and even safety issues. In this paper, we first demonstrate the inorganic–organic coating via advanced molecular layer deposition (alucone) as a protective layer for metallic Na anode. By protecting Na anode with controllable alucone layer, the dendrites and mossy Na formation have been effectively suppressed and the lifetime has been significantly improved. Moreover, the molecular layer deposition alucone coating shows better performances than the atomic layer deposition Al2O3 coating. The novel design of molecular layer deposition protected Na metal anode may bring in new opportunities to the realization of the next-generation high ene...

Journal ArticleDOI
TL;DR: It is demonstrated that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition.
Abstract: Artificial photosystems are advanced by the development of conformal catalytic materials that promote desired chemical transformations, while also maintaining stability and minimizing parasitic light absorption for integration on surfaces of semiconductor light absorbers. Here, we demonstrate that multifunctional, nanoscale catalysts that enable high-performance photoelectrochemical energy conversion can be engineered by plasma-enhanced atomic layer deposition. The collective properties of tailored Co3O4/Co(OH)2 thin films simultaneously provide high activity for water splitting, permit efficient interfacial charge transport from semiconductor substrates, and enhance durability of chemically sensitive interfaces. These films comprise compact and continuous nanocrystalline Co3O4 spinel that is impervious to phase transformation and impermeable to ions, thereby providing effective protection of the underlying substrate. Moreover, a secondary phase of structurally disordered and chemically labile Co(OH)2 is introduced to ensure a high concentration of catalytically active sites. Application of this coating to photovoltaic p+n-Si junctions yields best reported performance characteristics for crystalline Si photoanodes.

Journal ArticleDOI
TL;DR: In this paper, an atomic layer deposition (ALD) technology was used to fabricate a new class of CdS@ZnO core-shell heterostructure, which not only allows the light to be absorbed by Cdc core, but also provides an intimate heterojunction interface between ZnO shell and CcS core.

Journal ArticleDOI
TL;DR: In this paper, a review of ALD growth on 2D materials is reviewed and discussed with previously reported results to provide insights to readers who are investigating 2D material and relevant topics.
Abstract: 2D materials are layered crystalline materials and are the most attractive nanomaterials due to their potentials in next-generation electronics. Because most 2D materials are atomically thin, a suitable fabrication process without degradation of the original properties of the material is required to realize 2D-material-based devices. Atomic layer deposition (ALD) is an ideal technique for adding materials with atomic scaling precision to nanomaterials. Due to the surface-sensitive reactions of ALD, growth on 2D materials is strongly affected by the surface properties of the 2D materials. In this Perspective, ALD growth on 2D materials is reviewed and discussed with previously reported results to provide insights to readers who are investigating 2D materials and relevant topics.

Journal ArticleDOI
TL;DR: Li et al. as mentioned in this paper proposed a 3D carbon nanotube sponge (CNTS) as a Li deposition host, which enables homogenous charge distribution for Li nucleation and minimizes the effective current density to overcome dendrite growth.
Abstract: Lithium metal is considered the ideal anode material for Li-ion-based batteries because it exhibits the highest specific capacity and lowest redox potential for this type of cells. However, growth of Li dendrites, unstable solid electrolyte interphases, low Coulombic efficiencies, and safety hazards have significantly hindered the practical application of metallic Li anodes. Herein, we propose a three-dimensional (3D) carbon nanotube sponge (CNTS) as a Li deposition host. The high specific surface area of the CNTS enables homogenous charge distribution for Li nucleation and minimizes the effective current density to overcome dendrite growth. An additional conformal Al2O3 layer on the CNTS coated by atomic layer deposition (ALD) robustly protects the Li metal electrode/electrolyte interface due to the good chemical stability and high mechanical strength of the layer. The Li@ALD-CNTS electrode exhibits stable voltage profiles with a small overpotential ranging from 16 to 30 mV over 100 h of cycling at 1.0 mA·cm–2. Moreover, the electrodes display a dendrite-free morphology after cycling and a Coulombic efficiency of 92.4% over 80 cycles at 1.0 mA·cm–2 in an organic carbonate electrolyte, thus demonstrating electrochemical stability superior to that of planar current collectors. Our results provide an important strategy for the rational design of current collectors to obtain stable Li metal anodes.

Journal ArticleDOI
TL;DR: In this article, the authors report on atomic layer deposited Hf0.5Zr 0.5O2 (HZO)-based capacitors which exhibit excellent ferroelectric (FE) characteristics featuring a large switching polarization (45μC/cm2) and a low FE saturation voltage (∼1.5V) as extracted from pulse write/read measurements.
Abstract: We report on atomic layer deposited Hf0.5Zr0.5O2 (HZO)-based capacitors which exhibit excellent ferroelectric (FE) characteristics featuring a large switching polarization (45 μC/cm2) and a low FE saturation voltage (∼1.5 V) as extracted from pulse write/read measurements. The large FE polarization in HZO is achieved by the formation of a non-centrosymmetric orthorhombic phase, which is enabled by the TiN top electrode (TE) having a thickness of at least 90 nm. The TiN films are deposited at room temperature and annealed at 400 °C in an inert environment for at least 1 min in a rapid thermal annealing system. The room-temperature deposited TiN TE acts as a tensile stressor on the HZO film during the annealing process. The stress-inducing TiN TE is shown to inhibit the formation of the monoclinic phase during HZO crystallization, forming an orthorhombic phase that generates a large FE polarization, even at low process temperatures.

Journal ArticleDOI
TL;DR: In this article, an atomic layer deposition (ALD) approach was used to protect the surface of this cathode material powders from oxygen release during initial charge, which results in low initial coulombic efficiency, intense electrolyte oxidation and thermal instability.

Journal ArticleDOI
TL;DR: A review of the recent developments of ALD and MLD of materials that are gaining increasing attention on various substrates, with particular emphasis on high-surface-area substrates and a critical review ofthe effects of the process conditions, namely, temperature, pressure, and time on ALD growth.

Journal ArticleDOI
TL;DR: In this paper, an in-depth review of surface chemistry and reaction mechanism for controlled surface modification of polymeric materials by ALD is provided. But, the authors do not provide a detailed analysis of the reaction mechanism.

Journal ArticleDOI
Songtao Lu1, Huanhuan Wang1, Jia Zhou1, Xiaohong Wu1, Wei Qin1 
TL;DR: The facile but unique synthesis method demonstrated in this work for producing nanostructures rich in OVs and nanocomposites with strong coupling via interfacial molecular bindings could be extended to the synthesis of other oxide based anode materials and therefore could have general significance for developing high energy density lithium ion batteries.
Abstract: Although zinc oxide (ZnO), a low-cost and naturally abundant material, has a high theoretical specific capacity of 987 mA h g−1 for hosting lithium ions, its application as an anode material has been hindered by its rapid capacity fading, mainly due to a large volume change (around 228%) upon repeated charge–discharge cycles. Herein, using carbon black (CB) powder as a support, ZnO–carbon black (denoted as ZnO–CB) nanocomposites were successfully fabricated using the atomic layer deposition (ALD) method. This method was able to produce strong interfacial molecular bindings between ZnO nanoclusters and the carbon surface that provide stable and robust electrical contact during lithiation and delithiation processes, as well as ZnO nanoclusters rich in oxygen vacancies (OVs) for faster Li-ion transport. Overall, the nanocomposites were able to deliver a high discharge specific capacity of 2096 mA h g−1ZnO at 100 mA g−1 and stable cyclic stability with a specific capacity of 1026 mA h g−1ZnO maintained after 500 cycles. The composites also have excellent rate capability, and a reversible capacity at a high 1080 mA h g−1ZnO at 2000 mA g−1. The facile but unique synthesis method demonstrated in this work for producing nanostructures rich in OVs and nanocomposites with strong coupling via interfacial molecular bindings could be extended to the synthesis of other oxide based anode materials and therefore could have general significance for developing high energy density lithium ion batteries.

Journal ArticleDOI
Ning Li1, Jun Zhang1, Yu Tian1, Jianhui Zhao1, Jian Zhang1, Wei Zuo1 
TL;DR: A magnetically separable three-dimensional (3D) γ-Fe2O3@ZnO core-shell photocatalyst was successfully fabricated by hydrothermal sintering and a subsequent atomic layer deposition (ALD) method.

Journal ArticleDOI
TL;DR: The mechanism behind the experimental results is revealed by ex situ scanning electron microscope, X-ray powder diffraction, and electrochemical impedance spectroscopy (EIS) characterizations, which confirms that the ultrathin TiO2 modifications can prevent the structural degradation and the formation of SEI film of MoS2 electrode.
Abstract: We report the fabrication of 3D flower-like MoS2 nanosheets arrays on carbon cloth as a binder-free anode for sodium ion battery. Ultrathin and conformal TiO2 layers are used to modify the surface of MoS2 by atomic layer deposition. The electrochemical performance measurements demonstrate that the ALD TiO2 layer can improve the cycling stability and rate capability of MoS2. The MoS2 nanosheets with 0.5-nm TiO2 coating electrode show the highest initial discharge capacity of 1392 mA h g–1 at 200 mA g–1, which is increased by 53% compared with that of bare MoS2. After 150 cycles, the capacity retention rate of the TiO2-coated MoS2 achieves 75.8% of its second cycle’s capacity at 200 mA h g–1 in contrast to that of 59% of pure MoS2. Furthermore, the mechanism behind the experimental results is revealed by ex situ scanning electron microscope (SEM), X-ray powder diffraction (XRD), and electrochemical impedance spectroscopy (EIS) characterizations, which confirms that the ultrathin TiO2 modifications can preve...

Journal ArticleDOI
TL;DR: In this article, conformal, ultrathin aluminum oxide coatings on lithium were used to stabilize Li anodes for high performance energy storage devices such as Li-S batteries, and the results indicated that ALD Al2O3 coatings are a promising strategy to stabilize lithium anodes.
Abstract: Lithium metal is a highly desirable anode material for lithium batteries due to its extremely high theoretical capacity (3860 mA h g−1), low potential (−3.04 V versus standard hydrogen electrode), and low density (0.534 g cm−3). However, dendrite growth during cycling and low coulombic efficiency, resulting in safety hazards and fast battery fading, are huge barriers to commercialization. Herein, we used atomic layer deposition (ALD) to prepare conformal, ultrathin aluminum oxide coatings on lithium. We investigated the growth mechanism during Al2O3 ALD on lithium by in situ quartz crystal microbalance and found larger growth than expected during the initial cycles. We also discovered that the ALD Al2O3 enhances the wettability of the Li surface towards both carbonate and ether electrolytes, leading to uniform and dense SEI formation and reduced electrolyte consumption during battery operation. Scanning electron microscopy verified that the bare Li surfaces become rough and dendritic after electrochemical cycling, whereas the ALD Al2O3 coated Li surfaces remain smooth and uniform. Analysis of the Li surfaces after cycling using X-ray photoelectron spectroscopy and in situ transmission electron microscopy revealed that the ALD Al2O3 coating remains intact during electrochemical cycling, and that Li ions diffuse through the coating and deposit on the underlying Li. Coin cell testing demonstrated more than two times longer cycling life for the ALD Al2O3 protected Li, and a coulombic efficiency as high as ∼98% at a practical current rate of 1 mA cm−2. More significantly, when the electrolyte volume was reduced from 20 to 5 μL, the stabilizing effect of the ALD coating became even more pronounced and the cycling life was around four times longer. These results indicate that ALD Al2O3 coatings are a promising strategy to stabilize Li anodes for high performance energy storage devices such as Li–S batteries.

Journal ArticleDOI
TL;DR: Of the materials explored, TiO2 ALD layers lead to the most effective overall MOF/fiber adhesion, uniformity, and a rapid catalytic degradation rate for a CWA simulant, dimethyl p-nitrophenyl phosphate (DMNP) with t1/2 = 15 min, 580-fold faster than the catalytic performance of untreated PP textiles.
Abstract: Metal–organic frameworks (MOFs) chemically bound to polymeric microfibrous textiles show promising performance for many future applications. In particular, Zr-based UiO-66-family MOF-textiles have been shown to catalytically degrade highly toxic chemical warfare agents (CWAs), where favorable MOF/polymer bonding and adhesion are attained by placing a nanoscale metal-oxide layer on the polymer fiber preceding MOF growth. To date, however, the nucleation mechanism of Zr-based MOFs on different metal oxides and how product performance is affected are not well understood. Herein, we provide new insight into how different inorganic nucleation films (i.e., Al2O3, ZnO, or TiO2) conformally coated on polypropylene (PP) nonwoven textiles via atomic layer deposition (ALD) influence the quality, overall surface area, and the fractional yield of UiO-66-NH2 MOF crystals solvothermally grown on fiber substrates. Of the materials explored, we find that TiO2 ALD layers lead to the most effective overall MOF/fiber adhesio...

Journal ArticleDOI
TL;DR: In this article, a hybrid organic/inorganic artificial solid electrolyte interphase (ASEI) was used to stabilize Li metal anodes using self-healing electrochemical polymerization (EP) and atomic layer deposition (ALD).
Abstract: Li metal is among the most attractive anode materials for secondary batteries, with a theoretical specific capacity > 3800 mAh g–1. However, its extremely low electrochemical potential is associated with high chemical reactivity that results in undesirable reduction of electrolyte species on the lithium surface, leading to spontaneous formation of a solid electrolyte interphase (SEI) with uncontrolled composition, morphology, and physicochemical properties. Here, we demonstrate a new approach to stabilize Li metal anodes using a hybrid organic/inorganic artificial solid electrolyte interphase (ASEI) deposited directly on the Li metal surface by self-healing electrochemical polymerization (EP) and atomic layer deposition (ALD). This hybrid protection layer is thin, flexible, ionically conductive, and electrically insulating. We show that Li metal protected by the hybrid protection layer gives rise to very stable cycling performance for over 300 cycles at current density 1 mA/cm2 and over 110 cycles at curr...

Journal ArticleDOI
TL;DR: In this paper, the authors review the current state-of-the-art ALD for perovskite solar cells and explore other potential opportunities such as the fabrication of doped metal oxide selective contacts and transparent electrodes, also for use in tandem solar cell architectures, as well as barrier layers for encapsulation.
Abstract: Atomic layer deposition is widely acknowledged as a powerful technique for the deposition of high quality layers for several applications including photovoltaics (PV). The capability of ALD to generate dense, conformal, virtually pinhole-free layers becomes attractive also for the emerging organo-metal halide perovskite solar cells (PSCs), which have garnered the interest of the PV community through their remarkable efficiency gains, now over 20%, in just a few years of research. Until now, the application of ALD layers in PSCs has almost exclusively been restricted to the stages of device fabrication prior to perovskite deposition. Researchers have mainly focused on fabricating efficient electron and hole transport layers (TiO2, SnO2, ZnO, NiO) and ultra-thin Al2O3 or TiO2 passivation layers for several device configurations. The first section of this contribution reviews the current state-of-the-art ALD for perovskite solar cells. Then, we explore other potential opportunities, such as the fabrication of doped metal oxide selective contacts and transparent electrodes, also for use in tandem solar cell architectures, as well as barrier layers for encapsulation. Finally, we present our own experimental investigation of the challenges involved in depositing directly on perovskite absorbers in view of replacing organic electron and hole transport layers with ALD metal oxides (MOs). Therefore, the effects of temperature, oxidizing agents and metal precursors on perovskite are studied. A number of insights are gained which can lead to the development of ad hoc ALD processes that are compatible with the underlying perovskite, in this case, methylammonium lead iodide, MAPbI3. The phase purity and surface chemistry of the perovskite were used as metrics to quantify the feasibility of depositing selected MOs which can be adopted as selective contacts and passivation layers.

Journal ArticleDOI
TL;DR: For the first time, X-ray photoelectron spectroscopy is used to elucidate the cathode electrolyte interphase (CEI) on ALD-coated electrodes, which contains less carbonate species and more inorganic species, resulting in significant increase in Coulombic efficiency and decrease in cathode impedance.
Abstract: Atomic layer deposition (ALD) is a commonly used coating technique for lithium ion battery electrodes. Recently, it has been applied to sodium ion battery anode materials. ALD is known to improve the cycling performance, Coulombic efficiency of batteries, and maintain electrode integrity. Here, the electrochemical performance of uncoated P2-Na2/3Ni1/3Mn2/3O2 electrodes is compared to that of ALD-coated Al2O3 P2-Na2/3Ni1/3Mn2/3O2 electrodes. Given that ALD coatings are in the early stage of development for NIB cathode materials, little is known about how ALD coatings, in particular aluminum oxide (Al2O3), affect the electrode–electrolyte interface. Therefore, full characterizations of its effects are presented in this work. For the first time, X-ray photoelectron spectroscopy (XPS) is used to elucidate the cathode electrolyte interphase (CEI) on ALD-coated electrodes. It contains less carbonate species and more inorganic species, which allows for fast Na kinetics, resulting in significant increase in Coulo...

Journal ArticleDOI
TL;DR: Nb doping of two-dimensional (2D) MoSe2 layered nanomaterials is a promising approach to improve their gas sensing performance and could be precisely controlled by varying the number of Nb2O5 deposition cycles in the plasma enhanced atomic layer deposition process.
Abstract: Here, we report that Nb doping of two-dimensional (2D) MoSe2 layered nanomaterials is a promising approach to improve their gas sensing performance. In this study, Nb atoms were incorporated into a 2D MoSe2 host matrix, and the Nb doping concentration could be precisely controlled by varying the number of Nb2O5 deposition cycles in the plasma enhanced atomic layer deposition process. At relatively low Nb dopant concentrations, MoSe2 showed enhanced device durability as well as NO2 gas response, attributed to its small grains and stabilized grain boundaries. Meanwhile, an increase in the Nb doping concentration deteriorated the NO2 gas response. This might be attributed to a considerable increase in the number of metallic NbSe2 regions, which do not respond to gas molecules. This novel method of doping 2D transition metal dichalcogenide-based nanomaterials with metal atoms is a promising approach to improve the performance such as stability and gas response of 2D gas sensors.

Journal ArticleDOI
TL;DR: In this article, the use of ZnO nanorods prepared by hydrothermal self-assembly as the electron transport layer in perovskite solar cells was reported.
Abstract: Despite the considerably improved efficiency of inorganic–organic metal hybrid perovskite solar cells (PSCs), electron transport is still a challenging issue. In this paper, we report the use of ZnO nanorods prepared by hydrothermal self-assembly as the electron transport layer in perovskite solar cells. The efficiency of the perovskite solar cells is significantly enhanced by passivating the interfacial defects via atomic layer deposition of Al2O3 monolayers on the ZnO nanorods. By employing the Al2O3 monolayers, the average power conversion efficiency of methylammonium lead iodide PSCs was increased from 10.33% to 15.06%, and the highest efficiency obtained was 16.08%. We suggest that the passivation of defects using the atomic layer deposition of monolayers might provide a new pathway for the improvement of all types of PSCs..