Uniform arrays of gold nanoelectrodes with tuneable recess depth

• Elena O. Gordeeva,
• Ilya V. Roslyakov,
• Alexey P. Leontiev,
• Alexey A. Klimenko and
• Kirill S. Napolskii

Beilstein J. Nanotechnol. 2021, 12, 957–964, doi:10.3762/bjnano.12.72

• served as counter electrode. A saturated (KCl) Ag/AgCl electrode was used as a reference electrode (EAg/AgCl − ESHE = 0.197 V). All potentials hereinafter are given versus Ag/AgCl reference electrode. The length of the segments was controlled coulometrically. The Cu segments were electrodeposited using

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• Sabine Maier Meike Stohr Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erwin-Rommel-Str. 1, 91058 Erlangen, Germany Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands 10.3762/bjnano.12.71 Keywords: decoupling

• in notable effects on Ag(111) [75]. Although this decoupling concept is only practical on Cu, the fluorination significantly changed the molecular multilayer growth on Ag(111) and led to a physical decoupling with a nearly bulk crystalline structure for the fluorinated pentacene. Two articles within

• bandgap. Hence, Yousofnejad et al. [85] found using MoS2 on Ag(111) as substrate that the HOMO of tetracyanoquinodimethane (TNCQ) is not decoupled because it is located in the MoS2 valence band, while the lowest unoccupied molecular orbital narrows but still suffers from lifetime broadening because it is

Modification of a SERS-active Ag surface to promote adsorption of charged analytes: effect of Cu²⁺ ions

• Bahdan V. Ranishenka,
• Andrei Yu. Panarin,
• Irina A. Chelnokova,
• Sergei N. Terekhov,
• Peter Mojzes and
• Vadim V. Shmanai

Beilstein J. Nanotechnol. 2021, 12, 902–912, doi:10.3762/bjnano.12.67

• the electrostatic interaction between analyte molecules and silver nanoparticles (Ag NPs) on the intensity of surface-enhanced Raman scattering (SERS). For this, we fabricated nanostructured plasmonic films by immobilization of Ag NPs on glass plates and functionalized them by a set of differently

• the surface charge of the substrate, which tends to be negative. Using the data obtained and our model SERS system, we analyzed the modification of the Ag surface by different reagents (lithium chloride, polyethylenimine, polyhexamethylene guanidine, and multicharged metal ions). Finally, all those

• inversion of the analyte charge played a key role in this case, instead of a change of charge of the substrate surface. Changing the charge of analytes could be a promising way to get clear SERS spectra of negatively charged molecules on Ag SERS-active supports. Keywords: electrostatic interaction

The role of convolutional neural networks in scanning probe microscopy: a review

• Ido Azuri,
• Irit Rosenhek-Goldian,
• Neta Regev-Rudzki,
• Georg Fantner and
• Sidney R. Cohen

Beilstein J. Nanotechnol. 2021, 12, 878–901, doi:10.3762/bjnano.12.66

Silver nanoparticles nucleated in NaOH-treated halloysite: a potential antimicrobial material

• Yuri B. Matos,
• Rodrigo S. Romanus,
• Mattheus Torquato,
• Edgar H. de Souza,
• Rodrigo L. Villanova,
• Marlene Soares and
• Emilson R. Viana

Beilstein J. Nanotechnol. 2021, 12, 798–807, doi:10.3762/bjnano.12.63

• 10.3762/bjnano.12.63 Abstract Despite all recent advances in medical treatments, infectious diseases remain dangerous. This has led to intensive scientific research on materials with antimicrobial properties. Silver nanoparticles (Ag-NPs) are a well-established solution in this area. The present work

• studied the nucleation of silver on halloysite substrates modified by chemical treatment with NaOH. The resulting stabilized Ag-NPs were characterized by X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The nucleation was characterized by thermogravimetric

• analysis and differential scanning calorimetry. The antimicrobial properties of the Ag-NPs were investigated against E. coli and S. aureus. The potential of the Ag-NPs for industrial application was tested by dispersing them into low-density polyethylene. The importance of the chemical affinity between

Silver nanoparticles induce the cardiomyogenic differentiation of bone marrow derived mesenchymal stem cells via telomere length extension

• Khosro Adibkia,
• Ali Ehsani,
• Asma Jodaei,
• Ezzatollah Fathi,
• Raheleh Farahzadi and
• Mohammad Barzegar-Jalali

Beilstein J. Nanotechnol. 2021, 12, 786–797, doi:10.3762/bjnano.12.62

• possible combination of stem cells and nanotechnology in the treatment of diseases. This study aims to investigate the in vitro effect of silver nanoparticles (Ag-NPs) on the cardiomyogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs) through detection of cardiac markers. For

• this purpose, MSCs were isolated from bone marrow resident and differentiated to the cardiac cells using a dedicated medium with Ag-NPs. Also, the cardiomyogenic differentiation of BM-MSCs was confirmed using immunocytochemistry. Then, real-time PCR and western blotting assay were used for measuring

• absolute telomere length (TL) measurement, and gene and protein assessment of the cells, respectively. It was found that 2.5 µg/mL Ag-NPs caused elongation of the telomeres and altered VEGF, C-TnI, VWF, SMA, GATA-4, TERT, and cyclin D protein and gene expression in the cardiomyogenically differentiated BM

Fate and transformation of silver nanoparticles in different biological conditions

• Barbara Pem,
• Marija Ćurlin,
• Darija Domazet Jurašin,
• Valerije Vrček,
• Rinea Barbir,
• Vedran Micek,
• Raluca M. Fratila,
• Jesus M. de la Fuente and
• Ivana Vinković Vrček

Beilstein J. Nanotechnol. 2021, 12, 665–679, doi:10.3762/bjnano.12.53

• Silver (nano) that insufficient data on AgNP physicochemical properties and toxicology in cosmetics hinder the health hazards caused by AgNPs [5]. Earlier, the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) raised questions on how different forms of Ag used in consumer and

• patients that were overexposed to Ag via different routes [16][17][18][19][20]. In these patients, Ag granules were detected in the connective tissue of the dermis [18][20]. In fact, some Ag-containing drugs were retracted from clinical use due to the observed generalized argyria after long-term use or

• drug abuse [21]. Animal experiments demonstrated Ag accumulation in the liver, kidneys, brain, and testis after oral exposure to AgNPs; however, the chemical form of Ag remained undefined in these cases [22]. In media of high ionic strength and low pH the AgNPs aggregate and/or dissolve [23]. Under

High-yield synthesis of silver nanowires for transparent conducting PET films

• Gul Naz,
• Hafsa Asghar,
• Muhammad Ramzan,
• Muhammad Arshad,
• Rashid Ahmed,
• Muhammad Bilal Tahir,
• Bakhtiar Ul Haq,
• Nadeem Baig and
• Junaid Jalil

Beilstein J. Nanotechnol. 2021, 12, 624–632, doi:10.3762/bjnano.12.51

• the growth of rod-like structures, the longitudinal SPR of which might contribute to the advent of a peak at wavelengths shorter than 401 nm. When the reaction approached 20 min, the Ag nanorods further grew in length, and peak intensities continued to rise and become sharp followed by a gradual

• reaction temperature of 160 °C, the AgNO3/PVP ratio has also great effect on the morphology of AgNWs [53]. In our case, a 1:1 ratio of AgNO3/PVP started the growth of Ag nanoparticles, as can be seen in the SEM image in Figure 4a. Adding more PVP to the reaction promotes the formation of AgNWs. A AgNO3/PVP

• sheet resistance values if all Ag nanowires in the network are highly connected (at high coverage) [36]. The histogram in Figure 4d shows that some nanowires grow up to 5 µm in length. The aspect ratio calculated turns out to be more than 45. The length of silver nanowires can be controlled

Influence of electrospray deposition on C₆₀ molecular assemblies

• Antoine Hinaut,
• Sebastian Scherb,
• Sara Freund,
• Zhao Liu,
• Thilo Glatzel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2021, 12, 552–558, doi:10.3762/bjnano.12.45

• of the islands is found. Similar results are obtained for a Ag(111) surface, as shown in part 2 of Supporting Information File 1. The absence of favorable anchoring sites, similar to kinks in the herringbone reconstruction, on Ag(111) suggests that not only the adsorbed solvent molecules are

• assembly formation. Part 1 describes the Au(111) surface with a significant presence of solvent. Part 2 presents a comparison between HV-ESD and TE for the Ag(111) surface. Part 3 shows defect formation after HV-ESD on a KBr surface. Supporting Information File 46: Additional experimental data Funding

On the stability of microwave-fabricated SERS substrates – chemical and morphological considerations

• Limin Wang,
• Aisha Adebola Womiloju,
• Christiane Höppener,
• Ulrich S. Schubert and
• Stephanie Hoeppener

Beilstein J. Nanotechnol. 2021, 12, 541–551, doi:10.3762/bjnano.12.44

• additives to fabricate uniform Ag nanoparticles. These include basic aminoacids (such as ʟ-lysine or ʟ-arginine) and soluble starch or other additives, which act as reducing and protecting agents, respectively [22]. In our approach, the monolayer of silver nanoparticles is formed by the reduction of silver

• process. All substrates were characterized before the stability tests and revealed the formation of a reproducible monolayer of nanoparticles on the substrate, which is in line with the previously reported procedure. Typically, the Ag nanoparticles synthesized by the microwave-assisted synthesis approach

• can be found in Supporting Information File 1, Table S1. The observed band structure clearly identifies bands at 1394, 1440, and 1580 cm−1 which are indicative of 4,4’-dimercaptoazobenzene (DMAB), which is formed by an oxidative transformation of 4-ATP on Ag nanoparticle surfaces at higher laser power

Surface-enhanced Raman scattering of water in aqueous dispersions of silver nanoparticles

• Paulina Filipczak,
• Krzysztof Hałagan,
• Jacek Ulański and
• Marcin Kozanecki

Beilstein J. Nanotechnol. 2021, 12, 497–506, doi:10.3762/bjnano.12.40

• discovery of the SERS effect in 1974 [27], most of the research is focused on biomolecules and medical applications [28][29]. The SERS effect of water has been studied since 1980. There are reports on the SERS effect of water in aqueous solutions of electrolytes placed between metal electrodes (Ag, Au, Cu

• molecules interacting directly with the surface of AgNPs was estimated based on the size and shape of AgNPs in the AgNPs blue sample, which was determined by TEM (Figure 1), and on the Ag concentration in the dispersion (17.96 µg/mL), which was determined by flame atomic absorption spectrometry (FAAS). It

• simultaneously an analyte and it is in a much higher concentration than the substrate itself. However, a stronger SERS effect could be induced by the water molecules in the nearest vicinity of the Ag surface. Therefore, the number of water molecules directly interacting with AgNPs was estimated and used to

Interface interaction of transition metal phthalocyanines with strontium titanate (100)

• Reimer Karstens,
• Thomas Chassé and
• Heiko Peisert

Beilstein J. Nanotechnol. 2021, 12, 485–496, doi:10.3762/bjnano.12.39

• 100 (X-ray photoelectron diffraction) or 150 (monochromatized X-ray photoelectron spectroscopy) hemispherical analyzers (SPECS), and a four-grid LEED optics (SpectaLEED, Omicron, Germany). The PES binding energy scale is calibrated to reproduce the binding energies of Cu 2p3/2 (932.6 eV), Ag 3d5/2

• multiplet structure arising from final-state effects due to the overlap of Co 2p and Co 3d wave functions. The shape of satellite structures above 780 eV for the reduced Co ion in CoPc is discussed for the CoPc/Ag interface in [58]. Since satellite features in Figure 4c appear in the same energy range as

Rapid controlled synthesis of gold–platinum nanorods with excellent photothermal properties under 808 nm excitation

• Jialin Wang,
• Qianqian Duan,
• Min Yang,
• Boye Zhang,
• Li Guo,
• Pengcui Li,
• Wendong Zhang and
• Shengbo Sang

Beilstein J. Nanotechnol. 2021, 12, 462–472, doi:10.3762/bjnano.12.37

• –Pt nanoparticles with adjustable LSPR wavelength range. In this work, the effects of Ag+ and K2PtCl4 on the deposition of Pt on the surface of gold nanorods (AuNRs) were investigated. A fast, precise, and controlled synthesis of dumbbell-like Pt-coated AuNRs (Au@Pt NRs) under mild conditions is

• significant part of the photon energy is absorbed through LSPR [1][2]. The LSPR effect excites the free conduction band electrons and energy is released in the form of heat through nonradiative decay [3][4]. Au, Ag, Pt, and other noble metal nanoparticles all exhibit an obvious LSPR effect and strong spectral

• al. synthesized bimetal noncompact dendritic Pt shell-decorated AuNRs with spatial control of the Pt growth [26]. Grzelczak et al. developed two different deposition modes of Pt on the surface of AuNRs by removing or keeping the Ag+ ions used in the formation of AuNRs [27]. However, these studies

A review on nanostructured silver as a basic ingredient in medicine: physicochemical parameters and characterization

• Gabriel M. Misirli,
• Kishore Sridharan and
• Shirley M. P. Abrantes

Beilstein J. Nanotechnol. 2021, 12, 440–461, doi:10.3762/bjnano.12.36

• prominent {111} facets. In addition to prioritizing the characterization we have also discussed the importance of quantifying AgNPs and silver ion content (Ag+) and their different mechanisms at the chemical, biological, pharmacological, and toxicological levels. The mechanism of action of AgNPs against

• various bacteria and viruses including the SARS-CoV-2 was analyzed in order to understand its effectiveness as an antimicrobial agent with therapeutic efficacy and low toxicity. Further, there is the need to characterize AgNPs and quantify the content of free Ag+ for the implementation of new systematic

• {111} facets were found to be responsible for the antibacterial activity of AgNPs, a fact that was confirmed by a death study whose kinetics were supported by the arrangement of Ag-resistant genes in the genome of the test organism [46]. Conversely, AgNPs with different sizes exhibit different

Reconstruction of a 2D layer of KBr on Ir(111) and electromechanical alteration by graphene

• Zhao Liu,
• Antoine Hinaut,
• Stefan Peeters,
• Sebastian Scherb,
• Ernst Meyer,
• Maria Clelia Righi and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2021, 12, 432–439, doi:10.3762/bjnano.12.35

• ]. Compared to the adsorption energy, the ionic interaction within the layer is typically stronger such that structural deformations are weak [25]. However, it was demonstrated that a NaCl adlayer on Ag(100), besides strongly reducing the overall work function, can create clearly modulated dipole moment

• densities corresponding to the registry of the NaCl layer in respect to the substrate [26][27]. But also the formation of a weak structural deformation observed as superstructure has been reported for (100) oriented surfaces, for example, for KCl and NaCl on Ag(100) [28][29] or KBr on Cu(100) [30]. In

• the compensated bias voltage of −430 mV, presenting several holes and fuzzy edges. Remarkably, the growth of the islands mainly occurs at the middle of the Ir terraces, rather than at step edges as observed, for example, for NaCl on Ag(111) [33] or graphene (GR) on Ir(111) [38][39]. Also, the

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• [42]. With the addition of Ag nanoparticles to a dispersion of SnO2/rGO, the working temperature was dropped from 55 °C to room temperature in the gas sensing of NO2 [43]. (For further examples and comparison with other gas sensors see Table S1 in Supporting Information File 1.) The ternary Ni@rGO/WO3

• oxidation and thermal reduction process using natural graphite (type KFL 99.5 from AMG Mining AG, former Kropfmühl AG, Passau, Germany) as starting material. Graphite was oxidized according to [67]. Reduction of the graphite oxide was performed at 400 °C. Before using rGO in the nanoparticle synthesis, it

• placed in a tube furnace with a temperature regulator. To enhance electrical conductivity and to improve contact Ag electrodes were deposited on parallel sides of the pellets. The measurement procedure was carried out for NO2 and acetone in a stationary regime in a precisely controlled atmosphere (10 ppm

Exploring the fabrication and transfer mechanism of metallic nanostructures on carbon nanomembranes via focused electron beam induced processing

• Christian Preischl,
• Linh Hoang Le,
• Elif Bilgilisoy,
• Armin Gölzhäuser and
• Hubertus Marbach

Beilstein J. Nanotechnol. 2021, 12, 319–329, doi:10.3762/bjnano.12.26

• without any changes, aside from oxidation. Here we demonstrate that iron as well as cobalt oxide structures on top of a cross-linked SAM on Ag/mica do change more significantly. The Fe(NO3)3 solution used for etching of the Ag layer also dissolves the cobalt oxide structures and causes dissolution and

• satisfying results [4][9]. However, for certain precursors, EBID yields clean deposits when carried out under ultrahigh vacuum (UHV) conditions. It was shown that in UHV, for some precursors, an autocatalytic growth (AG) process occurs already at room temperature, which leads, upon further precursor dosage

• , to the dissociation of the precursor molecules on top of the initial EBID deposit. In the case of Fe(CO)5 this AG process results in the formation of deposits consisting of pure iron [10]. A second method from the FEBIP family, namely electron beam-induced surface activation (EBISA), also largely

Characterization, bio-uptake and toxicity of polymer-coated silver nanoparticles and their interaction with human peripheral blood mononuclear cells

• Sahar Pourhoseini,
• Reilly T. Enos,
• Angela E. Murphy,
• Bo Cai and
• Jamie R. Lead

Beilstein J. Nanotechnol. 2021, 12, 282–294, doi:10.3762/bjnano.12.23

• aggregation of NPs was observed in the RPMI medium over the exposure time (24 h). A dose-dependent relationship between PBMC uptake and Ag concentration was detected for both AgNP and AgNO3 treatment. There was approximately a two-fold increase in cellular Ag uptake in the AgNO3 vs the NP treatment

• . Cytotoxicity, using LDH and MTS assays and based on exposure concentrations was not significantly different when comparing NPs and Ag ions. Based on differential uptake, AgNPs were more toxic after normalizing toxicity to the amount of cellular Ag uptake. Our data highlights the importance of correct synthesis

• colonization on different surfaces, such as catheters and prostheses [13][14], which raises concern about Ag release in the body and their potential negative impact on human health. For instance, the silver concentration in the blood of people without any occupational or medicinal exposure is less than 1 µg·L

Gold(I) N-heterocyclic carbene precursors for focused electron beam-induced deposition

• Cristiano Glessi,
• Aya Mahgoub,
• Cornelis W. Hagen and
• Mats Tilset

Beilstein J. Nanotechnol. 2021, 12, 257–269, doi:10.3762/bjnano.12.21

• iodides [48]. For the triazolium salt the two alkylation reactions were carried out together in a one-pot synthesis [36]. The resulting salts were then reacted with silver oxide to generate the respective Ag(I) NHC complexes. Upon the addition of 1 equiv of gold precursor Au(SMe2)Cl in situ, a

The nanomorphology of cell surfaces of adhered osteoblasts

• Christian Voelkner,
• Mirco Wendt,
• Regina Lange,
• Max Ulbrich,
• Martina Gruening,
• Susanne Staehlke,
• Barbara Nebe,
• Ingo Barke and
• Sylvia Speller

Beilstein J. Nanotechnol. 2021, 12, 242–256, doi:10.3762/bjnano.12.20

• measurement of I–V characteristics [21]. The bias voltage applied between pipette and bath electrode was approximately 100 mV. Both electrodes were non-polarizable (Ag/AgCl). For SICM topography measurements the nanopipette approached the surface until the setpoint of 0.98 nA (corresponding to an ion current

A review on the biological effects of nanomaterials on silkworm (Bombyx mori)

• Sandra Senyo Fometu,
• Guohua Wu,
• Lin Ma and
• Joan Shine Davids

Beilstein J. Nanotechnol. 2021, 12, 190–202, doi:10.3762/bjnano.12.15

• ), graphene oxide, silver nanoparticles (Ag NPs) [24][25][26], quantum dots, and superparamagnetic particles [27] have been reported to have antibacterial properties against Streptococcus mutans [28] and Xanthomonas perforans, antifungal properties against Fusarium oxysporum [27] and Fusarium graminearum [29

• triethoxycaprylylsilane: 130 nm, size of non-functionalized nanoparticles: 100 nm). Conversely, mice exposed to 100 mg/mL of Ag NM (<20 nm) exhibited no adverse effects on the lungs [38]. Also, anatase TiO2 NM was reported to induce pulmonary inflammation in mice models [39]. Kim et al. reported that male Sprague-Dawley

• uptake of carbon black and single-walled nanotubes caused impairment in the locomotor function of these flies. Demir et al. [42] reported that Ag NPs (0.1, 1, 5, and 10 mM) induced genotoxicity in the wing spot assay of fruit flies via somatic recombination. Carmona et al. [43] reported cytotoxic effects

Paper-based triboelectric nanogenerators and their applications: a review

• Jing Han,
• Nuo Xu,
• Yuchen Liang,
• Mei Ding,
• Junyi Zhai,
• Qijun Sun and
• Zhong Lin Wang

Beilstein J. Nanotechnol. 2021, 12, 151–171, doi:10.3762/bjnano.12.12

• main materials utilized on those P-TENGs were commercial tissue paper and silver nanowires (Ag NWs), which were key to their feasibility. The P-TENGs were built with two conductive paper pieces as the electrodes, which were sandwiched between two commercial tissue paper pieces. Three basic operation

A review on the green and sustainable synthesis of silver nanoparticles and one-dimensional silver nanostructures

• Sina Kaabipour and
• Shohreh Hemmati

Beilstein J. Nanotechnol. 2021, 12, 102–136, doi:10.3762/bjnano.12.9

• methods. The first category consists of techniques that use chemical reagents to reduce Ag cations into zero-charged Ag atoms, which then mount on top of the nuclei, serving as templates for crystal growth into particles at the nanoscale [138][139]. This set of techniques is also known as the “chemical

• ], microalgae [189][190][191][192][193], enzymes [194][195][196], saccharides [197][198][199][200][201], and vitamins [202][203][204] to synthesize Ag nanostructures with controlled size and morphology. These methods can also be referred to as a subcategory of green synthesis. Numerous works in the literature

• rate, and narrow size distribution can be achieved by this method [108]. The process uses a laser beam at high energy to ablate pure Ag from which the separated AgNPs, either in liquid or vapor form, are attained and confined in the surrounding ambient [109]. The formation of nanoparticles by laser

Fusion of purple membranes triggered by immobilization on carbon nanomembranes

• René Riedel,
• Natalie Frese,
• Fang Yang,
• Martin Wortmann,
• Raphael Dalpke,
• Daniel Rhinow,
• Norbert Hampp and
• Armin Gölzhäuser

Beilstein J. Nanotechnol. 2021, 12, 93–101, doi:10.3762/bjnano.12.8

• fluorescence micrographs. Funding This work was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Cluster of Excellence “Macromolecular Complexes” Frankfurt, DFG grant GO 918/14-1 to AG, DFG grant HA 2906/9-1 to NH, and DFG grant RH 134/1-1 to DR.

Atomic layer deposited films of Al₂O₃ on fluorine-doped tin oxide electrodes: stability and barrier properties

• Hana Krýsová,
• Michael Neumann-Spallart,
• Hana Tarábková,
• Pavel Janda,
• Ladislav Kavan and
• Josef Krýsa

Beilstein J. Nanotechnol. 2021, 12, 24–34, doi:10.3762/bjnano.12.2

• studies, Al2O3 films on FTO were exposed, at various time intervals and at room temperature, to 1 M NaOH, 1 M H2SO4, and buffered solution (pH 7.2). Electrochemical experiments were carried out in a single-compartment three-electrode cell using a Zahner workstation. The reference electrode was Ag/AgCl (3

• 7.2). Chronoamperometric measurements were performed in buffered solution (pH 7.2) at −1.2 V (vs Ag/AgCl). The morphology of the films was characterized ex situ, under ambient conditions, by atomic force microscopy (AFM, Dimension Icon, Bruker, USA) in a semicontact (tapping) mode. A silicon

• polarization at −1.2 V vs Ag/AgCl, the reduction of FTO to tin took place (Equation 1). No Sn was found when the FTO layers were protected by alumina films (Figure 9). Conclusion ALD Al2O3 films, already at a thickness of 5 nm, exhibited very good blocking of the electron transport from solid electrodes (FTO