Search results

Search for "atomic layer deposition" in Full Text gives 93 result(s) in Beilstein Journal of Nanotechnology.

Atomic layer deposition for efficient oxygen evolution reaction at Pt/Ir catalyst layers

  • Stefanie Schlicht,
  • Korcan Percin,
  • Stefanie Kriescher,
  • André Hofer,
  • Claudia Weidlich,
  • Matthias Wessling and
  • Julien Bachmann

Beilstein J. Nanotechnol. 2020, 11, 952–959, doi:10.3762/bjnano.11.79

Graphical Abstract
  • of the salts followed by their thermal decomposition. In the alternative method, more academic in nature, atomic layer deposition (ALD) is applied to the felts after anodization. ALD allows for a controlled coating with ultralow noble-metal loadings in narrow pores. In acidic electrolyte, the ALD
  • approach yields improved mass activity (557 A·g−1 as compared to 80 A·g−1 at 0.39 V overpotential) on the basis of the noble-metal loading, as well as improved stability. Keywords: atomic layer deposition (ALD); oxygen evolution reaction (OER); redox flow battery; vanadium–air redox flow battery (VARFB
  • the Ti support and subsequent thermal decomposition to the corresponding elements [16][17][18]. As an academic method yielding better control of the electrode surface geometry, we perform an “anodization” of the Ti fibers to generate an ordered porous layer, followed by atomic layer deposition (ALD
PDF
Album
Full Research Paper
Published 22 Jun 2020

Band tail state related photoluminescence and photoresponse of ZnMgO solid solution nanostructured films

  • Vadim Morari,
  • Aida Pantazi,
  • Nicolai Curmei,
  • Vitalie Postolache,
  • Emil V. Rusu,
  • Marius Enachescu,
  • Ion M. Tiginyanu and
  • Veaceslav V. Ursaki

Beilstein J. Nanotechnol. 2020, 11, 899–910, doi:10.3762/bjnano.11.75

Graphical Abstract
  • radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE) [2][7][10][11], DC [12][13] and RF [1][3][6] magnetron sputtering, pulsed laser deposition (PLD) [14][15], plasma-enhanced atomic layer deposition (PE-ALD) [16], chemical vapor deposition (CVD) [17], metal–organic chemical vapor deposition
PDF
Album
Full Research Paper
Published 12 Jun 2020

Effect of Ag loading position on the photocatalytic performance of TiO2 nanocolumn arrays

  • Jinghan Xu,
  • Yanqi Liu and
  • Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

Graphical Abstract
  • template (AAO) has constituted an important advance in the field of film preparation, since it allows the formation of nanostructured films with a high degree of morphology control [22]. Furthermore, according to Das et al. [23], the use of atomic layer deposition (ALD) for the preparation of TiO2 films
  • solar energy harvesting in photovoltaic and photocatalytic applications owing to their extremely high visible-light absorption and tuned effective band gap. In this work, Ag-loaded TiO2 nanocolumn (Ag-TNC) arrays were fabricated based on anodic aluminum oxide (AAO) template by combining atomic layer
  • deposition (ALD) and vacuum evaporation. The effects of the Ag loading position and deposition thickness, and the morphology, structure and composition of Ag-deposited TNC arrays on its optical and photocatalytic properties were studied. The Ag-filled TiO2 (AFT) nanocolumn arrays exhibited higher removal
PDF
Album
Full Research Paper
Published 05 May 2020

DFT calculations of the structure and stability of copper clusters on MoS2

  • Cara-Lena Nies and
  • Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

Graphical Abstract
  • enable the use of 2D materials in technology applications, processes have been developed to grow 2D materials via chemical vapour deposition (CVD) [16][17] and atomic layer deposition (ALD) [18][19]. The films prepared via thin film deposition were comparable in performance to materials obtained via
PDF
Album
Supp Info
Full Research Paper
Published 26 Feb 2020

Abrupt elastic-to-plastic transition in pentagonal nanowires under bending

  • Sergei Vlassov,
  • Magnus Mets,
  • Boris Polyakov,
  • Jianjun Bian,
  • Leonid Dorogin and
  • Vahur Zadin

Beilstein J. Nanotechnol. 2019, 10, 2468–2476, doi:10.3762/bjnano.10.237

Graphical Abstract
  • extreme surface-to-volume ratio. If surface nucleation is mitigated by, for example, external materials (coating), the onset of plastic yield can be significantly postponed. Hence, we performed a few preliminary tests on Ag NWs coated by atomic layer deposition (ALD) with a few-nm thick layer of alumina
PDF
Album
Supp Info
Full Research Paper
Published 12 Dec 2019

Semitransparent Sb2S3 thin film solar cells by ultrasonic spray pyrolysis for use in solar windows

  • Jako S. Eensalu,
  • Atanas Katerski,
  • Erki Kärber,
  • Lothar Weinhardt,
  • Monika Blum,
  • Clemens Heske,
  • Wanli Yang,
  • Ilona Oja Acik and
  • Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 2396–2409, doi:10.3762/bjnano.10.230

Graphical Abstract
  • employing an 87 nm thick Sb2S3 thin film absorber grown by atomic layer deposition (ALD) [18], whereas a PCE of 4.25% was reported when using Sb2S3 layers grown by CBD [21]. Unfortunately, the Sb2O3 impurity phase, which is considered detrimental to PV performance, unavoidably forms in the bulk of the Sb2S3
PDF
Album
Supp Info
Full Research Paper
Published 06 Dec 2019

Facile synthesis of carbon nanotube-supported NiO//Fe2O3 for all-solid-state supercapacitors

  • Shengming Zhang,
  • Xuhui Wang,
  • Yan Li,
  • Xuemei Mu,
  • Yaxiong Zhang,
  • Jingwei Du,
  • Guo Liu,
  • Xiaohui Hua,
  • Yingzhuo Sheng,
  • Erqing Xie and
  • Zhenxing Zhang

Beilstein J. Nanotechnol. 2019, 10, 1923–1932, doi:10.3762/bjnano.10.188

Graphical Abstract
  • . deposited iron oxide on CNTs by atomic layer deposition (ALD) and the obtained CNTs@Fe2O3 presented a specific capacitance of 580.6 F·g−1 at 5 A·g−1 [21]. Zhang et al. used magnetron sputtering to prepare sandwich-like CNT@Fe2O3@C structures, and the composite exhibited a specific capacitance of 787.5 F·g−1
PDF
Album
Supp Info
Full Research Paper
Published 23 Sep 2019

Novel hollow titanium dioxide nanospheres with antimicrobial activity against resistant bacteria

  • Carol López de Dicastillo,
  • Cristian Patiño,
  • María José Galotto,
  • Yesseny Vásquez-Martínez,
  • Claudia Torrent,
  • Daniela Alburquenque,
  • Alejandro Pereira and
  • Juan Escrig

Beilstein J. Nanotechnol. 2019, 10, 1716–1725, doi:10.3762/bjnano.10.167

Graphical Abstract
  • this work, novel, hollow, calcined titanium dioxide nanospheres (CSTiO2) were successfully synthesized for the first time through the combination of electrospinning and atomic layer deposition techniques. Poly(vinylpyrrolidone) (PVP) electrosprayed spherical particles were double-coated with alumina
  • ; atomic layer deposition; electrospinning; hollow nanospheres; titanium dioxide; Introduction Microbial contamination and the increase of multidrug bacterial resistance have become two major current concerns for food safety and human health due to the number of food-borne diseases and nosocomial
  • [10][15]. In this work, the combination of electrospinning and atomic layer deposition (ALD) technologies are presented as an innovative strategy to develop titanium dioxide hollow nanospheres with controlled and homogeneous dimensions. Electrospinning is a technique able to produce different
PDF
Album
Supp Info
Full Research Paper
Published 19 Aug 2019

Growth of lithium hydride thin films from solutions: Towards solution atomic layer deposition of lithiated films

  • Ivan Kundrata,
  • Karol Fröhlich,
  • Lubomír Vančo,
  • Matej Mičušík and
  • Julien Bachmann

Beilstein J. Nanotechnol. 2019, 10, 1443–1451, doi:10.3762/bjnano.10.142

Graphical Abstract
  • films of LiH. This theoretical reaction is self-saturating and, therefore, follows the principles of solution atomic layer deposition (sALD). Therefore, in this work the sALD technique and principles have been employed to experimentally prove the possibility of LiH deposition. The formation of
  • precursors and at temperatures not suitable for conventional ALD. Keywords: lithiated thin films; lithium hydride; solution atomic layer deposition (sALD); Introduction While the development of electric motors and semiconductor devices is progressing, the pressure on battery development is increasing
  • addressed for more general applicability. To meet this challenge, the use of atomic layer deposition (ALD) has been proposed [2][3]. The inherent conformity of ALD indeed allows for thinner, conformal, pin-hole free films [4][5]. ALD has been instrumental in enabling the development of nanobatteries
PDF
Album
Full Research Paper
Published 18 Jul 2019

On the transformation of “zincone”-like into porous ZnO thin films from sub-saturated plasma enhanced atomic layer deposition

  • Alberto Perrotta,
  • Julian Pilz,
  • Stefan Pachmajer,
  • Antonella Milella and
  • Anna Maria Coclite

Beilstein J. Nanotechnol. 2019, 10, 746–759, doi:10.3762/bjnano.10.74

Graphical Abstract
  • /bjnano.10.74 Abstract The synthesis of nanoporous ZnO thin films is achieved through annealing of zinc-alkoxide (“zincone”-like) layers obtained by plasma-enhanced atomic layer deposition (PE-ALD). The zincone-like layers are deposited through sub-saturated PE-ALD adopting diethylzinc and O2 plasma with
  • crystal growth occurred, giving insights in the manufacturing of nanoporous ZnO from Zn-based hybrid materials. Keywords: calcination; PE-ALD; porosity; thin films; ZnO; Introduction Atomic layer deposition (ALD) and molecular layer deposition (MLD) are sequential self-limiting vapor-phase deposition
PDF
Album
Supp Info
Full Research Paper
Published 21 Mar 2019

Biocompatible organic–inorganic hybrid materials based on nucleobases and titanium developed by molecular layer deposition

  • Leva Momtazi,
  • Henrik H. Sønsteby and
  • Ola Nilsen

Beilstein J. Nanotechnol. 2019, 10, 399–411, doi:10.3762/bjnano.10.39

Graphical Abstract
  • .; Eidet, J. R. J. Biomed. Mater. Res., Part A 2018, 106, 3090–3098. doi:10.1002/jbm.a.36499]. The growth was followed by in situ quartz crystal microbalance (QCM) measurements and all systems exhibited atomic layer deposition (ALD) type of growth. The adenine system has an ALD temperature window between
  • response [9]. Thus, the tailoring of the surface of materials used in tissue engineering is important for designing bioactive and biocompatible materials. Our choice is the atomic layer deposition/molecular layer deposition (ALD/MLD) technique by which organic–inorganic materials are developed through the
  • layer deposition (ALD) [17]. A coating produced by the ALD/MLD methods can render a non-biocompatible surface of an implant into a biocompatible material, allowing for the use of alternative materials as implants [18]. Moreover, ALD can provide specialized surface functionalities useful for biological
PDF
Album
Supp Info
Full Research Paper
Published 08 Feb 2019

Uniform Sb2S3 optical coatings by chemical spray method

  • Jako S. Eensalu,
  • Atanas Katerski,
  • Erki Kärber,
  • Ilona Oja Acik,
  • Arvo Mere and
  • Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 198–210, doi:10.3762/bjnano.10.18

Graphical Abstract
  • chemical bath deposition (CBD) [3][4], spin coating [5], atomic layer deposition (ALD) [6] or chemical spray pyrolysis (CSP) [7] method, has been applied in extremely thin absorber (ETA) solar cells due to its excellent absorption coefficient in the visible light spectrum (1.8 × 105 cm−1 at 450 nm) [1][2
PDF
Album
Supp Info
Full Research Paper
Published 15 Jan 2019

Electrostatic force microscopy for the accurate characterization of interphases in nanocomposites

  • Diana El Khoury,
  • Richard Arinero,
  • Jean-Charles Laurentie,
  • Mikhaël Bechelany,
  • Michel Ramonda and
  • Jérôme Castellon

Beilstein J. Nanotechnol. 2018, 9, 2999–3012, doi:10.3762/bjnano.9.279

Graphical Abstract
  • nm) were deposited or grown over the whole sample surface. Aluminum oxide (Al2O3) shells were prepared using the atomic layer deposition (ALD) method, polyvinyl acetate (PVAc) shells by spin coating, and silicon dioxide (SiO2) shells by plasma sputtering deposition (PSD). The signature of each
  • [54]. Shells Alumina thin layers: atomic layer deposition (ALD). The ALD method was used to grow Al2O3 layers on the nanoparticles [55][56]. ALD is a thin film deposition technique where the film thickness is precisely controlled at the atomic level [57]. The deposition is based on sequential chemical
PDF
Album
Full Research Paper
Published 07 Dec 2018

Controlling surface morphology and sensitivity of granular and porous silver films for surface-enhanced Raman scattering, SERS

  • Sherif Okeil and
  • Jörg J. Schneider

Beilstein J. Nanotechnol. 2018, 9, 2813–2831, doi:10.3762/bjnano.9.263

Graphical Abstract
  • Scientific UV–vis spectrophotometer (Evolution 600). The water contact angle was measured using a Krüss DSA 30 model drop-shape analysis system. The water contact angle was measured by placing 5 µL water droplets on the silver surface. Atomic layer deposition (ALD) of Al2O3 Silver films on glass substrates
PDF
Album
Supp Info
Full Research Paper
Published 07 Nov 2018

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

  • Muhammad Imran,
  • Nunzio Motta and
  • Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

Graphical Abstract
PDF
Album
Supp Info
Review
Published 13 Aug 2018

Spin-coated planar Sb2S3 hybrid solar cells approaching 5% efficiency

  • Pascal Kaienburg,
  • Benjamin Klingebiel and
  • Thomas Kirchartz

Beilstein J. Nanotechnol. 2018, 9, 2114–2124, doi:10.3762/bjnano.9.200

Graphical Abstract
  • apparently different mechanisms governing film formation in the Sb-BDC and Sb-TU processes. Most deposition methods such as chemical bath deposition [2][41], atomic layer deposition [22][32], thermal evaporation [33][35][46] and the here-discussed spin-coating [29][37] produce amorphous films that are
  • with respect to the corresponding literature reports. The Sb-BDC process with P3HT as HTM marks one of the highest efficiencies for planar Sb2S3 solar cells and is only outdone by fabrication via cumbersome atomic layer deposition [32] as can be seen from Figure 1. In analogy to [68] the losses
  • ][5][6][29] reach the highest efficiencies. Planar devices have been produced via various methods such as atomic layer deposition (ALD) [32], chemical bath deposition (CBD) [27] and (rapid) thermal evaporation (R)TE [33][34][35]. As the latest development, spin-coated planar solar cells [31][36][37
PDF
Album
Supp Info
Full Research Paper
Published 08 Aug 2018

Localized photodeposition of catalysts using nanophotonic resonances in silicon photocathodes

  • Evgenia Kontoleta,
  • Sven H. C. Askes,
  • Lai-Hung Lai and
  • Erik C. Garnett

Beilstein J. Nanotechnol. 2018, 9, 2097–2105, doi:10.3762/bjnano.9.198

Graphical Abstract
  • carriers (Figure 2). An 18 nm amorphous TiO2 layer was conformally deposited on the silicon nanostructures by using atomic layer deposition (ALD). This layer assists with charge separation, stabilizes the silicon surface and helps to passivate trap states, leading to well-known improvements in photo
  • . Formation of TiO2 using atomic layer deposition A custom-built atomic layer deposition system was used for the deposition of thin and compact TiO2 layers on the silicon nanostructures. For 18 nm TiO2 layers, subsequent injection of MilliQ water (18.2 MΩ·cm) and 99.995 % TiCl4 (for 10 ms each) took place in
PDF
Album
Supp Info
Full Research Paper
Published 03 Aug 2018

Self-assembled quasi-hexagonal arrays of gold nanoparticles with small gaps for surface-enhanced Raman spectroscopy

  • Emre Gürdal,
  • Simon Dickreuter,
  • Fatima Noureddine,
  • Pascal Bieschke,
  • Dieter P. Kern and
  • Monika Fleischer

Beilstein J. Nanotechnol. 2018, 9, 1977–1985, doi:10.3762/bjnano.9.188

Graphical Abstract
  • , different techniques such as reactive ion etching, thermal evaporation and atomic layer deposition can be used in combination with BCML [13][14][15]. Here it is important to choose the optimum chain length of the diblock copolymers for obtaining the desired inter-particle spacing [16][17]. It is thus
PDF
Album
Full Research Paper
Published 12 Jul 2018

Synthesis of hafnium nanoparticles and hafnium nanoparticle films by gas condensation and energetic deposition

  • Irini Michelakaki,
  • Nikos Boukos,
  • Dimitrios A. Dragatogiannis,
  • Spyros Stathopoulos,
  • Costas A. Charitidis and
  • Dimitris Tsoukalas

Beilstein J. Nanotechnol. 2018, 9, 1868–1880, doi:10.3762/bjnano.9.179

Graphical Abstract
  • fragile coatings that tend to fracture under small loads, making them in many cases unsuitable for industrial use. Mechanical reinforcement is necessary to improve mechanical stability. Some proposed methods in this direction are calcination [28], atomic layer deposition [29], hydrothermal treatment [30
PDF
Album
Supp Info
Full Research Paper
Published 27 Jun 2018

Magnetic properties of Fe3O4 antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

  • Juan L. Palma,
  • Alejandro Pereira,
  • Raquel Álvaro,
  • José Miguel García-Martín and
  • Juan Escrig

Beilstein J. Nanotechnol. 2018, 9, 1728–1734, doi:10.3762/bjnano.9.164

Graphical Abstract
  • .9.164 Abstract Magnetic films of magnetite (Fe3O4) with controlled defects, so-called antidot arrays, were synthesized by a new technique called AFIR. AFIR consists of the deposition of a thin film by atomic layer deposition, the generation of square and hexagonal arrays of holes using focused ion beam
  • variable lattice parameters. Keywords: antidot arrays; atomic layer deposition; focused ion beam; magnetic properties; thermal reduction; Introduction Magnetic antidots, magnetic thin films with periodic arrays of holes, are currently an important topic for both the fundamental understanding of low
  • atomic layer deposition (ALD) [31][32][33]. Due to the self-limited growth of material, ALD allows to control the thickness of the films with high precision [34]. The holes arise because of a dewetting process of the sample [35], which depends on its geometric and magnetic parameters as well as on the
PDF
Album
Full Research Paper
Published 11 Jun 2018

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

  • Hana Krýsová,
  • Josef Krýsa and
  • Ladislav Kavan

Beilstein J. Nanotechnol. 2018, 9, 1135–1145, doi:10.3762/bjnano.9.105

Graphical Abstract
  • prevent recombination on this surface [3][4][5]. Blocking layers (BLs) can be fabricated by spray pyrolysis [3][6], magnetron sputtering [7], electrochemical deposition [8] spin coating [9][10], dip coating [11] and atomic layer deposition (ALD) [3]. From the viewpoint of low-cost processing and easy
PDF
Album
Supp Info
Full Research Paper
Published 10 Apr 2018

Effect of annealing treatments on CeO2 grown on TiN and Si substrates by atomic layer deposition

  • Silvia Vangelista,
  • Rossella Piagge,
  • Satu Ek and
  • Alessio Lamperti

Beilstein J. Nanotechnol. 2018, 9, 890–899, doi:10.3762/bjnano.9.83

Graphical Abstract
  • this work, we investigate the effect of thermal treatment on CeO2 films fabricated by using atomic layer deposition (ALD) on titanium nitride (TiN) or on silicon (Si) substrates. In particular, we report on the structural, chemical and morphological properties of 25 nm thick ceria oxide with particular
  • deposition process. This result is interpreted in the light of the contributions of different energy components (surface energy and elastic modulus) which act dependently on the substrate properties, such as its nature and structure. Keywords: atomic layer deposition; cerium(IV) oxide (CeO2) microstructure
  • sputtering [7], e-beam [16], physical vapor deposition [17], chemical vapor deposition (CVD) [18], and atomic layer deposition (ALD). The latter has been explored by using different precursors, e.g., Ce(thd)4, Ce(iPrCp)3 and Ce(mmp)4) [19][20][21][22][23], obtaining as-deposited film with polycrystalline
PDF
Album
Full Research Paper
Published 15 Mar 2018

Dynamics and fragmentation mechanism of (C5H4CH3)Pt(CH3)3 on SiO2 surfaces

  • Kaliappan Muthukumar,
  • Harald O. Jeschke and
  • Roser Valentí

Beilstein J. Nanotechnol. 2018, 9, 711–720, doi:10.3762/bjnano.9.66

Graphical Abstract
  • fragmentation pathways qualitatively. In a recent investigation, thickness-controlled site-selective Pt deposits were obtained by direct atomic layer deposition (ALD) in which ALD was performed on EBID patterned substrates. In this ALD process, an O2 pulse is used to obtain better nucleation, even though the
  • layer deposition (ALD) conditions are available [12]. The studies in this review fairly agree that (1) the presence of surface hydroxyl groups are the source for protons that help in the evolution of H2, CH4 and H2O during the deposition process, and (2) the molecules dissociate or associate through a
  • bonds directly to three methyl groups and a methylated cyclopentadienyl ring is a widely used precursor to obtain Pt deposits. Although the dissociation mechanism of (C5H4CH3)Pt(CH3)3 leading to the Pt deposit remains unknown, studies for a family of precursors similar to (C5H4CH3)Pt(CH3)3 in atomic
PDF
Album
Full Research Paper
Published 23 Feb 2018

Al2O3/TiO2 inverse opals from electrosprayed self-assembled templates

  • Arnau Coll,
  • Sandra Bermejo,
  • David Hernández and
  • Luís Castañer

Beilstein J. Nanotechnol. 2018, 9, 216–223, doi:10.3762/bjnano.9.23

Graphical Abstract
  • errors and Al2O3/TiO2 as a structural layer infiltrated through the voids. This is a two-step atomic layer deposition (ALD) process in which the polymeric template is eliminated after the deposition of the alumina layer and before the ALD deposition of the titania layer. Results and Discussion The
  • dislocations in between, and no cracks were present. Atomic layer deposition The second step of our fabrication procedure uses the polystyrene structure shown in Figure 2 as a template in which other suitable materials can be deposited. In our case, alumina was first deposited as it is a material that can be
PDF
Album
Full Research Paper
Published 19 Jan 2018

Atomic layer deposition and properties of ZrO2/Fe2O3 thin films

  • Kristjan Kalam,
  • Helina Seemen,
  • Peeter Ritslaid,
  • Mihkel Rähn,
  • Aile Tamm,
  • Kaupo Kukli,
  • Aarne Kasikov,
  • Joosep Link,
  • Raivo Stern,
  • Salvador Dueñas,
  • Helena Castán and
  • Héctor García

Beilstein J. Nanotechnol. 2018, 9, 119–128, doi:10.3762/bjnano.9.14

Graphical Abstract
  • grown by atomic layer deposition (ALD) at 400 °C. Metastable phases of ZrO2 were stabilized by Fe2O3 doping. The number of alternating ZrO2 and Fe2O3 deposition cycles were varied in order to achieve films with different cation ratios. The influence of annealing on the composition and structure of the
  • with a Zr/Fe atomic ratio of 2.0. Keywords: atomic layer deposition; metal oxides; thin films; Introduction Doped ZrO2 has been a subject of interest because of several potential applications, for example, in microelectronics as a memory material [1]. Also, doping a dielectric film with a magnetic
  • deposited ZrO2 were compared from the viewpoint of ferroelectric behavior [21], whereby ALD precursors were Zr-based metal organic precursors (TEMAZr) and H2O. Both fabrication methods provided samples with antiferroelectric behavior. Here, ZrO2 films doped with Fe2O3 were grown by atomic layer deposition
PDF
Album
Full Research Paper
Published 10 Jan 2018
Other Beilstein-Institut Open Science Activities