Doctor Blade Process Research Articles

Manufacturing of carbon-supported platinum cathodes for proton exchange membrane fuel cell using the doctor blade process: Microstructure and performance

Catalyst layers (CL, the anode and cathode) properties do influence the performance of proton exchange membrane fuel cells (PEMFC). CLs are prepared by depositing an ink made from a catalyst (carbon-supported Pt-based nanoparticles, NPs) and an ionomer in appropriate solvents on a substrate, followed by post-treatment (solvent evaporation, calendaring, hot-pressing). The literature rarely provides details and characterizations about CLs fabrication. This contribution investigates a way to prepare Pt/VC (Pt NPs supported on Vulcan XC72 carbon-black) and Pt/GC (Pt NPs supported on graphitized-carbon-black) PEMFC CLs. The ink formulation, mixing and deposition methods are evaluated and the areal homogeneity/texture of the formed CLs thoroughly characterized by scanning electron microscopy and X-Ray fluorescence. Light-ball-milling mixing enables to prepare homogeneous and agglomerate-free inks without degrading the Pt/C catalysts. The optimal ionomer-to-carbon ratio differs for Pt/GC and Pt/VC CLs; it not only depends on the BET surface area of the carbon substrate and its outer apparent surface (apparent carbon particles diameter), but should also be adapted to physicochemical surface properties of the Pt/C sample. Optimized I/C = 1–1.2 enables to improve the performance of Pt/GC cathodes by ca. 300 % versus I/C = 0.5 (at 80 °C, 80%RH), owing to hugely-depreciated proton-transport-resistance in the CL.

Constraining the Excessive Aggregation of Non-Fullerene Acceptor Molecules Enables Organic Solar Modules with the Efficiency >16.

Translating high-performance organic solar cell (OSC) materials from spin-coating to scalable processing is imperative for advancing organic photovoltaics. For bridging the gap between laboratory research and industrialization, it is essential to understand the structural formation dynamics within the photoactive layer during printing processes. In this study, two typical printing-compatible solvents in the doctor-blading process are employed to explore the intricate mechanisms governing the thin-film formation in the state-of-the-art photovoltaic system PM6:L8-BO. Our findings highlight the synergistic influence of both the donor polymer PM6 and the solvent with a high boiling point on the structural dynamics of L8-BO within the photoactive layer, significantly influencing its morphological properties. The optimized processing strategy effectively suppresses the excessive aggregation of L8-BO during the slow drying process in doctor-blading, enhancing thin-film crystallization with preferential molecular orientation. These improvements facilitate more efficient charge transport, suppress thin-film defects and charge recombination, and finally enhance the upscaling potential. Consequently, the optimized PM6:L8-BO OSCs demonstrate power conversion efficiencies of 18.42% in small-area devices (0.064 cm2) and 16.02% in modules (11.70 cm2), respectively. Overall, this research provides valuable insights into the interplay among thin-film formation kinetics, structure dynamics, and device performance in scalable processing.

A universal hole transport layer for efficient organic solar cells processed by blade coating

Doctor-blade coating technology is a roll-to-roll compatible high-throughput thin film fabrication route. In this work, doctor-blading was applied for fabricating organic solar cells (OSCs) using a polyoxometalates material phosphomolybdic acid (PMA) as a hole transport layer (HTL). Compared to PEDOT:PSS, PMA-based devices demonstrate lower trap-assisted recombination, higher hole mobility, prolonged charge carrier lifetime and faster charge collection. With PM6:Y6 as active layer, PMA-based device delivered a high power conversion efficiency (PCE) of 17.79 % with a boosted short-circuit current density (JSC) value of 28.08 mA/cm2, which is one of the best performances for PM6:Y6-based solar cells through doctor-blading process. In addition, the performance improvement was observed in both conventional and inverted structured devices with various donor: acceptor combinations. These results indicate the high universality of PMA for printable processing and its prospect in preparation of the industrial production of OSCs.

Cationic Zr-based metal-organic framework via post-synthetic alkylation for selective adsorption and separation of anionic dyes

Adsorption and separation of toxic organic dyes are of great importance in wastewater treatment and dye recycling. In this work, cationic metal-organic framework MIL-140C–2NMe+ with triangular hydrophobic channels was prepared in which methyl groups were added to the pyridyl sites of the ligand [2,2'-bipyridine]-5,5'-dicarboxylic acid (H2bpydc) via post-synthetic alkylation reaction. MIL-140C–2NMe+ can be used as an efficient adsorbent for the selective adsorption and separation of anionic dyes in the aqueous mixture of cationic/anionic dyes. Specifically, the adsorption capacities of MIL-140C–2NMe+ for anionic methyl orange can reach 310 mg/g in 10 min. With a facile doctor-blading process, we have also polymerized the MIL-140C–2NMe+ nanocrystals and polyvinylidene fluoride (PVDF) polymer to fabricate a flexible and self-supporting mixed matrix membrane (MMM), which can selectively capture and separate the anionic organic dyes from the binary dye mixtures.

Flexible Double-Sided Light-Emitting Devices Based on Transparent Embedded Interdigital Electrodes.

In the areas of flexible displays and wearable devices, double-sided light-emitting devices have huge commercial applications. Here, we provide a novel form of flexible double-sided light-emitting devices by designing and manufacturing different transparent interdigital electrodes for lighting the structural areas of composite emitting layers. The transparent interdigital electrodes are fabricated by embedding multiwalled carbon nanotubes in interdigital mesh-structured microcavities using a doctor-blading process, and the emitting layers are fabricated by mixing copper-doped zinc sulfide (ZnS/Cu) phosphor particles with the transparent polydimethylsiloxane polymer. The fabricated double-sided light-emitting devices could be in the crimp state, exhibiting excellent flexibility. By designing the structure of the interdigital electrodes and the thickness of the emitting layers, the double-sided emission intensity of the light-emitting devices can be adjusted. Furthermore, based on the flexible double-sided light-emitting devices, various patterns can be successfully programed, such as the digital, grayscale, and ancient Chinese walls. The flexible and programmable double-sided light-emitting films provide a promising strategy for the next generation of customized flexible displays.

Fully Doctor-bladed efficient perovskite solar cells in ambient condition via composition engineering

Abstract It is very meaningful to develop large-scale, low-cost technology for fabricating efficient perovskite solar cells (PSCs) to accelerate their commercialization. Doctor-blading is one of important scalable technologies for processing PSCs, but the power conversion efficiencies (PCEs) of fully doctor-bladed PSCs, including electron transport layer, perovskite layer and hole transport layer, are still lag far behind the PSCs fabricated via conventional spin-coating technology, especially fabricated in ambient condition. Herein, highly efficient planar heterojunction PSCs with a structure of ITO/SnO2/FAxMA(1-x)PbIyBr(3-y)/Spiro-OMeTAD/Ag are achieved by fully doctor-blading technique in ambient condition, in which high-quality perovskite films with low trap-density are fabricated via two-step sequential deposition with a low temperature process by simultaneously introducing composition engineering and additive-doping technology. Organic cation is added into the PbI2 precursor to reduce the uneven distribution of nucleation sites in the perovskite films during doctor-blading process and promote the uniform growth of perovskite grain. Moreover, 2,3,5,6-tetrafluoro-7,7,8,8-tetra-cyanoquinodimethane (F4-TCNQ) acted as the doping additive is employed into perovskite, resulting in healing the perovskite grain boundary and reducing trap-density accordingly. As a result, the doctor-bladed PSCs fabricated in ambient condition exhibit the champion PCE of 18% and a stabilized efficiency of 17.7%. Furthermore, PSCs fabricated via fully doctor-blading in ambient condition achieve the PCE of 17.0% with negligible hysteresis. This work provides an important strategy for scalable fabrication of efficient PSCs in ambient condition and potentially accelerates the commercialization.

3D Printing of Bioinspired Structural Materials with Fibers Induced by Doctor Blading Process

Fiber is a crucial element in biological micro-structural materials. Replication of fiber-reinforced composites with analogous architectures of their natural counterparts has caused widespread academic concern. Recent researches indicate 3D printing technology has the potential to produce biomimetic structural materials. The aim of this study is to develop a process to fabricate fiber-reinforced composites with ordered yet spatially tunable fiber arrangement. Specifically, we present a method to align fibers during the 3D printing of fiber-reinforced composites. A modified slurry-based stereolithography process was developed, and the fibers in the fiber–resin mixture were aligned by Shear force produced during the spreading of slurry. We investigated the influence of relative factors on fiber orientation, and two models were used to uncover the internal mechanism. By controlling the speed and the direction of the moving blade, the patterns that fibers were arranged can be freely programmed. Therefore, we have extracted bioinspired sinusoidal and zigzag design motifs to analyze their mechanical properties compared with non-bioinspired motifs. The proposed method is relatively material agnostic, more efficient and more facile. It thus provides a promising route to fabricate fiber-reinforced composites, and has potential to be adopted in biological structures researches and industrial applications.

气相辅助刮刀涂布法制备钙钛矿薄膜

气相辅助刮刀涂布法制备钙钛矿薄膜

Tuning the Properties of CZTS Films by Controlling the Process Parameters in Cost-Effective Non-vacuum Technique

Highly dispersive Cu2ZnSnS4 (CZTS) nanoparticles were successfully synthesized by a simple solvothermal route. A low cost, non-vacuum method was used to deposit CZTS nanoparticle ink on glass substrates by a doctor blade process followed by selenization in a tube furnace to form Cu2ZnSn (S,Se)4 (CZTSSe) layers. Different selenization conditions and particle concentrations were considered in order to improve the crystallinity and surface morphology; the annealing temperature was varied between 400°C and 550°C and the annealing time was varied between 5 min and 20 min in a selenium-nitrogen atmosphere. The influence of annealing conditions on structural, compositional, optical and electrical properties of CZTSSe thin films was studied. An improvement in the structural and surface morphology was observed with increasing of annealing temperature (up to 500°C). An enhancement in the crystallinity and surface morphology were observed for thin films annealed for 10–15 min. Absorption study revealed that the band gap energy of as-deposited CZTS thin film was approximately 1.43 eV, while for CZTSSe thin films it ranged from 1.15 eV to 1.34 eV at different annealing temperatures, and from 1.33 eV to 1.38 eV for different annealing times.

Highly thermally conductive layered polymer composite from solvent-exfoliated pristine graphene

Highly thermally conductive polymer composites are urgently required to resolve the heat dissipation issue of rapidly evolving electronic devices. Owing to two-dimensional plane structure and extremely high thermal conductivity, graphene is an ideal thermally conductive filler for polymer composites. In view of the increasing maturity of solvent exfoliation technique and its ability to produce high-quality graphene on a large scale at low cost, we aim to develop highly thermally conductive polymer composites from solvent-exfoliated, plane defect-free graphene, instead of oxidation-exfoliated, plane defect-rich graphene. Solvent-exfoliated pristine graphene/poly(vinylidene fluoride) composites with well-ordered layered structure are produced through a simple, scalable doctor-blading process. The combination of high-quality solvent-exfoliated pristine graphene and well-ordered layered microstructure forms high-efficiency, directional and dense pathways for phonon transport, and thus endows the polymer composites with high thermal conductivities (41.64 W/mK), surpassing the previously reported oxidation-exfoliated graphene-based polymer composites (2.1–19.5 W/mK). It provides a new route to fabricate highly thermally conductive composites from solvent-exfoliated pristine graphene.

Molecular doping enabled scalable blading of efficient hole-transport-layer-free perovskite solar cells

The efficiencies of perovskite solar cells (PSCs) are now reaching such consistently high levels that scalable manufacturing at low cost is becoming critical. However, this remains challenging due to the expensive hole-transporting materials usually employed, and difficulties associated with the scalable deposition of other functional layers. By simplifying the device architecture, hole-transport-layer-free PSCs with improved photovoltaic performance are fabricated via a scalable doctor-blading process. Molecular doping of halide perovskite films improved the conductivity of the films and their electronic contact with the conductive substrate, resulting in a reduced series resistance. It facilitates the extraction of photoexcited holes from perovskite directly to the conductive substrate. The bladed hole-transport-layer-free PSCs showed a stabilized power conversion efficiency above 20.0%. This work represents a significant step towards the scalable, cost-effective manufacturing of PSCs with both high performance and simple fabrication processes.

The preparation, microstructure and mechanical properties of a dense MgO-Al2O3-SiO2 based glass-ceramic coating on porous BN/Si2N2O ceramics.

A dense MgO–Al2O3–SiO2 based glass-ceramic coating was prepared by a doctor blade process on a porous BN/Si2N2O ceramic surface followed by heat treatment at 1050 °C under nitrogen flow. The phase composition, microstructure, mechanical properties and water absorption of the coating were studied. The coating consisted of α-cordierite phase with a small amount of glass phase. The dense coating without pores and cracks was favorable to seal and densify the porous ceramic surface due to part of the molten glass infiltrating the surface pores. The coating was defect-free and tightly bonded to the substrate because of a larger bonding area between the coating and the substrate. The elastic modulus and bending strength of the glass-ceramic coating were 37.9 GPa and 67.1 MPa, respectively. Moreover, the coated samples had a high Vickers hardness and low water absorption.

High performance carbon black counter electrodes for dye-sensitized solar cells

Carbon black (CB) thin films are prepared using a doctor blade process and utilized as counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). Poly(vinylidene fluoride) (PVDF) is used as a binder to regulate the viscosity of the CB paste to facilitate the doctor blade process. The PVDF is then removed via thermal treatment at 350 or 450 °C. The effects of CB composition (8-15 wt%) and the heat-treatment temperature on the electrochemical properties of the CB electrodes are studied, as well as on the performance of the corresponding DSSCs. The results show that, after the heat treatment, all CB films demonstrate a mesoporous structure. Film thickness increases with increased CB concentration. CB films heat-treated at 350 °C exhibit low electrochemical activity, high charge transfer resistance, and poor performance when utilized in DSSCs. These results are attributed to the presence of residual PVDF. By elevating the treating temperature to 450 °C, PVDF is completely removed and the electrochemical properties of the resultant CB films resemble closely those of platinum (Pt) film. The DSSCs using these CB CEs achieve conversion efficiencies (8.27–8.35%) comparable to cells using Pt (8.29%).

Formation and Characterization of a Well-Packed Particulate Structure Consisted of Cu Nanoparticles By Capillary Force for Low Resistivity at Low Temperature

Cu nanoparticles (NPs) have been studied extensively to develop nano ink for printable electronics on flexible substrates because of its low cost, high conductivity and low sintering temperature. Although there are many synthesis methods with low resistivity which normally require high temperature, high pressure, toxic regent and special equipment, it was difficult to achieve the practical use of Cu NPs because the synthesis methods are expensive. We have developed a facile and green synthesis method of Cu NPs by using water, citric acid, ascorbic acid as solvent, complex/capping agent and reducing agent, respectively. The particle size of the citric acid modified Cu NPs can be controlled from 30 nm to 10 µm by varying pH and concentrations of Cu ion and ascorbic acid. For low resistivity, a high packing density of the Cu NPs is required to increase the interparticulate junction area before heat treatment because the well-packed particulate structure leads to a low temperature densification reaction of metal NPs. We have succeeded in increasing the interparticulate junction area by combining with the Cu NPs and the micro-sized particles (MPs). The bimodal size distribution leads to the high packing density because small particles are placed in voids of packing large particles. However, the resistivity of the Cu particles (32 µΩ・cm) after heat treatment at 200oC is far from that of bulk Cu (1.7 µΩ・cm) because the Cu MPs prevent low temperature sintering of the mixture. Therefore, a well-packed particulate structure consisted only of Cu NPs is require for low resistivity at low temperature. In this study, capillary forces generated from solvents evaporation were utilized to obtain the high packing density of the Cu NPs for low resistivity at low temperature because capillary forces have been applied to obtain closely packed various NPs. For characterizations of Cu films prepared from the Cu NPs, XRD, FT-IR, SEM and XPS measurement were carried out. Besides, the electrical resistivity of Cu films after heat treatment was measured. Since the citric acid modified Cu NPs can well disperse in alcohols and boiling points of alcohols are relatively low as compared other organic solvents, alcohols are suitable to form stable Cu ink and use capillary forces. Cu films were prepared from drop casting of the Cu alcohol ink and doctor blade process using Cu NPs paste consisted of the Cu NPs and α-terpineol as a traditional method. The weight of these Cu films is controlled to be approximately the same. After dry treatment of the Cu films, the thickness of the Cu film (8 µm) prepared from the Cu alcohol ink is much thinner than that (30 µm) of prepared from the Cu paste. The high packing density of the Cu NPs arises from capillary forces during alcohol evaporation. After heat treatment at 200oC under Ar+H2 (98%+2%), the resistivities of the Cu films obtained from the Cu ink and the Cu paste are 7 µΩ・cm and 80 µΩ・cm, respectively. It was found that the well-packed particulate structure consisted only of Cu NPs by capillary forces facilitates a densification by heat treatment, resulting in the low resistivity at low temperature. In our presentation, detailed results about the Cu films prepared from the Cu ink will be introduced. This work was supported by JSPS KAKENHI Grant-in-Aid for Young Scientists (B) 15K16155.

Investigation of the Effects of Formulation, Slurry Preparation and Coating Conditions on the Mechanical Properties and Electrochemistry of Carbon-Based Lithium-Ion Battery Electrodes

Typically, new electrode materials for lithium-ion batteries are first tested on the laboratory-scale. Although this generally gives a good indication of the electrochemical performance of the active materials (e.g. specific charge and potential profile), it does not paint the whole picture: Electrode materials that look promising on the laboratory-scale might not necessarily turn out to be suitable for industrial applications, and vice versa. In particular, the upscaling to industrial quantities might pose significant challenges related to various processing issues (e.g. mixing, rheology and coatability). Therefore, it is essential to follow up on laboratory-scale experiments with larger-scale coating tests. We investigated various formulations containing synthetic graphite negative electrode material (IMERYS Graphite & Carbon) and tested the electrochemical performance of the resulting electrodes. Instead of applying the common laboratory-scale doctor blading process, the slurry was cast onto copper foil using the technically relevant comma-bar method on an industrial coating line. We investigated the effects of various parameters, such as formulation and preparation of the aqueous slurry (e.g. mixing conditions), binder and electrode additives, as well as coating conditions (e.g. continuous/intermittent and unpressed/pressed) on the homogeneity (e.g. thickness, mass and density distribution), adhesion (peeling strength) and electrochemistry (cycling behavior) of the resulting electrodes. The experiments showed that the solid content and the mixing conditions as well as the coating mode (continuous/intermittent) and calendering process (unpressed/pressed) have a significant influence on the properties of the final electrodes. A higher solid content generally resulted in more homogeneous electrodes due to less sagging (gravity induced flow). Increased shear rates and mixing times, on the other hand, led to better electrochemical properties due to a more effective dispersion process. Furthermore, continuous coating allowed the preparation of more homogeneous electrodes than intermittent coating. Finally, calendering (which, of course, reduces the electrode thickness and increases the electrode density) resulted in improved adhesion and a more homogeneous thickness distribution, while negatively affecting the density distribution. The methodology offers a useful way of further evaluating active material candidates that have been shown to be promising in laboratory-scale electrochemical experiments with regard to the electrode engineering and manufacturing on the pilot-scale and thus provides important information for the development of electrode materials.

Impact of capping during the formation of Cu2ZnSn(S,Se)4 thin films

Major challenge for the fabrication of kesterite absorber thin films such as CZTSSe (Cu2ZnSn(S,Se)4) is the volatility of chalcogens. Material loss and poor morphology are two key issues during high temperature annealing, carried out for the formation of CZTSSe thin film absorber layers. The purpose of the present study is to investigate the influence of capping during the crystallization of precursor to CZTSSe films via annealing. In this work, initial precursor was synthesized from elemental constituents by ball milling. CZTSSe films were deposited by doctor's blade process. Annealing was carried out in two different atmosphere viz. vacuum and inert gas. Both sets of samples were annealed with and without capping. We found significant changes for different annealing atmospheres. Capping has a positive influence on the film properties, revealed by structural, morphological and compositional analysis. Capping reduced material loss of volatile constituents and resulted compact crystalline films.

Fabrication of Cu2ZnSn(SxSe1 − x)4 solar cells by ethanol-ammonium solution process

In this paper, Cu2ZnSn(SxSe1−x)4 precursor films were produced by doctor blade process from SnS-Cu2O-ZnS slurry. To prepare the slurry, SnS, ZnS and Cu2O precipitates, which are outgrowths of stacked layer ZnS/Cu/SnS by CBD (chemical bath deposition)-annealing route, were dissolved in the mixture solvent of ethanol and NH3·H2O. Synthesized precursor films were then annealed at different conditions. The post-annealed films were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman measurements and UV–vis–NIR spectroscopy. SEM studies reveal that the rough and relatively compact absorber thin films are obtained via the sulfidation and sulfidation-selenization processes. X-ray diffraction and Raman spectrum results verify that the obtained films are composed of Cu2ZnSnS4 and Cu2ZnSnSe4 phases, which have high absorbance in visible range and direct band gap energy of 1.01–1.47eV. The best devices yield total area power conversion efficiency of 1.99% and 2.95% corresponding to Cu2ZnSnS4 and Cu2ZnSn(SxSe1−x)4 thin film solar cells under AM1.5 illumination without any anti-reflection layer.

Study on the fabrication of transparent electrodes by using a thermal-roll imprinted Ag mesh and anATO thin film

Transparent conductive films have been widely studied because of their potential applications in optoelectronic devices such as paper displays, dye-sensitized solar cells (DSSCs), organic lighting-emitting diodes (OLEDs), organic solar cells and so on. In this paper, we report on a low-resistance, a high-transparents conductive film that can be applied as It a flexible device substrate. In order to the fabricate transparent conductive film, we used a high-resolution roll imprinting method. The following steps were performed: The design and manufacture of an electroforming stamp mold, the fabrication of high resolution roll imprinted on flexible film, and the manufacture of an Ag grid that was filled by using a doctor blade process with a nano-sized Ag paste. Then on patterned Its films, antimony tin oxide was coated with ATO sol solution by using bar the coating method. The fabricated ATO/Ag mesh electrode showed good flexibility, and It exhibited a high optical transmittance of 85.3% in the visible wavelength and a sheet resistance of 41 Ω/sq. Furthermore, the bending test for mechanical properties showed that the ATO/Ag thin film had good flexibility.

Hematite nanorods Co-doped with Ru cations with different valence states as high performance photoanodes for water splitting

This work reports the synthesis and characterization of sub-10nm, porous Ru-doped α-Fe2O3 nanorods (NRs) as well as their implementation as photoanodes for water splitting. Highly photoactive Ru-doped α-Fe2O3 NR films were prepared by deposition of the ruthenium(III) acetylacetonate [Ru(acac)3]-treated presynthesized ultrathin α-FeOOH NR precursors onto FTO substrates via a doctor blading process, followed by annealing at 700°C in air. The photoelectrochemical (PEC) water splitting performance of the undoped and Ru-doped α-Fe2O3 NR photoanodes was characterized and optimized by varying the precursor molar ratio of α-FeOOH to Ru(acac)3. Significantly, under simulated 1 sun illumination, the optimized Ru-doped α-Fe2O3 NR films obtained at a Fe/Ru molar ratio of 100/5 yield a stable, record photocurrent density of ~5.7mAcm–2 and the highest incident photon to current conversion efficiencies (IPCEs) at 1.23V vs a reversible hydrogen electrode (RHE) and show an onset potential of anodic photocurrent around 0.7V vs RHE. The excellent PEC performance benefits from: (i) the simultaneously increased charge carrier concentration and mobility and (ii) charge balance provided by codoping of different valent Ru cations, resulting in a significant reduction of the defects that are supposed to serve as the recombination centers for photogenerated electrons and holes in the α-Fe2O3 lattice.

Structural and microwave properties of silica-coated NiFeMo flakes/polymer composites

The microwave properties of sheets containing silica-coated NiFeMo flakes are investigated and discussed according to the sheet structure, the silica layer uniformity and thickness. Commercial NiFeMo flakes are coated using the Stoeber method and embedded in polymer using the doctor blade process. The silica layer thickness is estimated by transmission electron microscopy (TEM) and the coating quality is probed by scanning electron microscopy (SEM). The in-plane orientation of magnetic moments within the sheet is evidenced by 57Fe Mössbauer spectrometry. As a result, the permittivity of composites is strongly reduced when the NiFeMo flakes are completely coated, whereas the permeability level is weakly and progressively altered when the silica thickness increases. We show that the frequency range for microwave absorption can be tuned according to the silica thickness and the flake loading. Reflection losses of −13 dB are obtained in the 1–2 GHz range for a normal incident electromagnetic wave interacting with 3 mm sheets backed by a perfect conductor and loaded with silica (90 nm width)-coated NiFeMo flakes.