Journal: Journal of Materials Chemistry C

Abbreviation

J. Mater. Chem. C

Publisher

Royal Society of Chemistry

Journal Volumes

ISSN

2050-7526
2050-7534

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2013 - 2019242020 - 202514
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Publications 1 - 10 of 38
  • The new material science towards sustainable robotics
    Item type: Review Article
    Miao, Wusha; Bai, Hedan (2024)
    Journal of Materials Chemistry C
    Sustainable robotics is an emerging field of research that aims to develop robotic automation solutions to address the United Nations' Sustainable Development Goals. The material-centric approach to sustainable robotics focuses on designing robots with novel sustainable materials starting from natural or recycled raw materials, demonstrating self-healing reusability, and eventually recycled, upcycled, or biodegraded with minimal environmental impact. The ultimate goal is to realize a physical robotic embodiment with a circular life-cycle. This perspective highlights recent advances in material science, ranging from self-healing materials to biodegradable and recyclable materials, which serve as the foundation for this emerging class of robots. We then showcase examples of functional material integration in sustainable robotic components and discuss challenges and opportunities towards an entirely sustainable robotic system.
  • Opto-electronics of PbS quantum dot and narrow bandgap polymer blends
    Item type: Journal Article
    Kahmann, Simon; Mura, Andrea; Protesescu, Loredana; et al. (2015)
    Journal of Materials Chemistry C
    Here we report on the interaction between the narrow bandgap polymer [2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta-[2,1-b;3,4-b]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) and lead sulphide (PbS) colloidal quantum dots (CQDs) upon photoexcitation. We show that the presence of both materials in a blend leads to a significant reduction of photoluminescence (PL) lifetime of the polymer. This observation is attributed, supported by transient absorption (TA) data, to an efficient electron transfer towards the QDs for excitons generated on the polymer. Furthermore, the ligand capping the QD surface exhibits a great impact on the dynamics of the PL, with the long-chain oleic acid (OA) largely suppressing any kind of interaction. By means of external quantum efficiency (EQE) measurements we find evidence that both components give rise to a contribution to the photocurrent, making this an interesting blend for future applications in hybrid organic–inorganic solar cells.
  • Self-organized spatio-temporal micropatterning in ferromagnetic Co-In films
    Item type: Journal Article
    Golvano-Escobal, Irati; Özkale, Berna; Suriñach, Santiago; et al. (2014)
    Journal of Materials Chemistry C
    Cobalt–indium (Co–In) heterogeneous films, featuring spatio-temporal patterns, have been electrodeposited in a chloride–citrate electrolyte. The Co content can be tuned from 25 at% to 90 at% by varying the applied current density between −10 and −30 mA cm−2. The spatio-temporal patterns consist of alternated dark and bright belts, which define micron-sized waves, targets and spirals. Cross-sectional images indicate layer-by-layer growth. Several crystallographic phases (hexagonal close-packed Co, face-centered cubic Co, tetragonal In and tetragonal CoIn3) are identified in the corresponding X-ray diffractograms. The films exhibit a combination of large hardness with relatively large Young's modulus and a soft-magnetic behaviour with tunable saturation magnetisation and coercivity (HC) values, mostly depending on the Co content and the effective magnetic anisotropy. The film with 90 at% Co shows the highest in-plane HC (275 Oe) and a squareness ratio close to 1. Magnetic force microscopy observations reveal that the self-patterning is not only topographic but also magnetic. These results demonstrate that the electrodeposition of spatio-temporal structures is a simple method to grow magnetically patterned films, over large areas, in a rapid and inexpensive way. This procedure is highly attractive for the implementation of new types of magnetic sensors, encoding magnetic stripes or even magnetic recording media.
  • ON/OFF switching of silicon wafer electrochemistry by pH-responsive polymer brushes
    Item type: Journal Article
    Panzarasa, Guido; Dübner, Matthias; Pifferi, Valentina; et al. (2016)
    Journal of Materials Chemistry C
    pH-Switchable electrochemical properties are demonstrated for the first time for native oxide-coated silicon wafer electrodes. Ultrathin and ultrathick pH-responsive poly(methacrylic acid) (PMAA) brushes, obtained by surface-initiated atom transfer radical polymerization, were used to achieve redox gating. PMAA brushes are reversibly switched between their protonated and deprotonated states by alternating acidic and basic pH, which corresponds to a swelling/collapsing behavior. As a result, the electrochemical properties of the PMAA brush-modified silicon electrode are switched “ON” and “OFF” simply by changing pH. The electrochemical properties of the modified electrode were examined by means of cyclic voltammetry and electrochemical impedance spectroscopy both in the absence and presence of ruthenium(III) hexamine, a well-known cationic redox probe.
  • High-temperature processable carbon-silicate nanocomposite cold electron cathodes for miniature X-ray sources
    Item type: Journal Article
    Longtin, Rémi; Elsener, Hans-Rudolf; Sanchez-Valencia, Juan Ramon; et al. (2013)
    Journal of Materials Chemistry C
  • Pyroelectricity in poled all-organic polar polynorbornene/polydimethylsiloxane-based stretchable electrets
    Item type: Journal Article
    Venkatesan, Thulasinath Raman; Owusu, Francis; Nüesch, Frank A.; et al. (2024)
    Journal of Materials Chemistry C
    Pyroelectricity in a recently developed all-organic composite electret with a polar polynorbornene-based filler and polydimethylsiloxane (PDMS) matrix has been studied with the help of thermal and dielectric techniques. Measurement of the pyroelectric p coefficient using a quasi-static periodic temperature variation at RT shows a non-linear dependence with the applied poling field, which is uncharacteristic of amorphous materials. Dielectric relaxation spectroscopy (DRS) and the thermally stimulated depolarization current (TSDC) technique reveal that this behaviour can be attributed to Maxwell-Wagner interface (MWI) polarization that occurs at the filler-matrix interface. These charges released during the onset of dipolar alpha and beta relaxations of the filler particles contribute majorly to the observed pyroelectricity at RT. The saturation of both MWI TSDC shoulders and spontaneous polarization at higher electric fields correlates with the p coefficient value reaching a plateau at these applied fields. A maximum p coefficient of 0.54 mu C m-2 K-1 is calculated for a poling field of 30 V mu m-1.
  • Synthesis and luminescence of Cs2HfCl6 micro- and Cs2HfF6 nanoparticles
    Item type: Journal Article
    Fellner, Madeleine; Lauria, Alessandro (2022)
    Journal of Materials Chemistry C
    Hafnium-based halide crystals are attractive wide-bandgap phosphor materials for scintillation applications due to their high density, low hygroscopicity and bright radioluminescence. Here, we describe synthetic approaches towards the formation of Cs2HfCl6 (CHC) microparticles and Cs2HfF6 (CHF) nanocrystals. The structure of the obtained materials was characterised by means of powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface chemistry was studied by attenuated total reflection infrared spectroscopy (ATR-IR) and dynamic light scattering (DLS) while thermal properties were determined with thermogravimetric analysis (TGA). The optical properties of the products were elucidated through absorption (UV-vis) and photoluminescence (PL/PLE) spectra. Intrinsically luminescent CHC can be synthesised as a micropowder through an emulsion synthesis. The synthesis of pure and Eu- or Mn-doped CHF nanopowders in organic solvents at 160 degrees C and atmospheric pressure is also disclosed. These materials might pave the way towards the versatile additive manufacturing of lead-free and dopant-free, particle-based scintillator materials.
  • Ligand-Assisted solid phase synthesis of mixed-halide perovskite nanocrystals for color-pure and efficient electroluminescence
    Item type: Journal Article
    Solari, Simon F.; Sudhir, Kumar; Jagielski, Jakub; et al. (2021)
    Journal of Materials Chemistry C
    Colloidal nanocrystals (NCs) of lead halide perovskites have generated considerable interest in the fabrication of optoelectronic devices, such as light emitting-diodes (LEDs), because of their tunable optical bandgap, narrow spectral width, and high defect tolerance. However, the inhomogeneous halide distribution within individual NCs remains a critical challenge in order to obtain color-stable electroluminescence in mixed-halide systems. Here, we demonstrate a new post-synthetic approach, ligand-assisted solid phase synthesis (LASPS), for the preparation of electroluminescent colloidal NCs of methylammonium (MA) lead halide perovskites, at room temperature. The slow reaction kinetics preserves the morphology, size, and shape in the resulting NCs whose emission covers the entire visible spectral region with photoluminescence (PL) quantum yields (QYs) of up to >90% and colloidal stability up to several months. The LEDs fabricated using the prepared mixed-halide NCs display narrowband electroluminescence (EL) ranging from 476 to 720 nm. The optimized red LEDs exhibit an external quantum efficiency, ηext, of up to 2.65%, with the CIE 1931 color coordinates of (0.705, 0.290), nearly identical to those of the red primary in the recommendation (rec.) 2020 standard (0.708, 0.292).
  • Role of Ln type in the physical mechanisms of defect mediated luminescence of Li, Ln-SnO2 nanoparticles
    Item type: Journal Article
    Cojocaru, Bogdan; Colbea, Claudiu; Avram, Daniel; et al. (2021)
    Journal of Materials Chemistry C
    Doping SnO2 with trivalent lanthanide (Ln) metals aiming at optical applications faces several challenges. The elastic and electrostatic misfit between bulkier Ln activators and Sn host cation induces strain in the lattice as well as defects as a result of charge-compensation. These effects can be partially healed by thermal annealing. However, dopant segregation which occurs above a certain temperature drives quenching of Ln emission. In this work, we explore Li co-doping as a vehicle to improve the luminescence of lanthanide (Eu, Sm, Er, Dy and, Tb) doped SnO2 nanoparticles. In case of substitutional Ln dopants (Eu, Sm and Er), Li enhances significantly the Ln luminescence up to 40-46 times. The luminescence enhancement induced by Li co-doping is explained by an interplay of removal of nearby oxygen vacancies (Eu, Sm), improved Ln doping homogeneity (Er) and, improved crystallinity (Eu, Sm, Er). The improved crystallinity caused by Li co-doping accounts for less than 30% of the total enhancement. In the case of surface Ln dopants (Dy and Tb), Li co-doping does not alter the Ln emission, either in shape or intensity. Only a few Dy dopants succeed to substitute for Sn in the rutile lattice as shown by single-photon counting investigations. Collectively, our results show that the extent of luminescence enhancement induced by Li co-doping depend strongly on the Ln type. In SnO2, the common mechanisms that explain the Li induced enhancement of Ln luminescence in various hosts, either contribute partially (improved crystallization) or do not contribute at all (local structure distortion). This journal is © The Royal Society of Chemistry.
  • Electrical characterization of nanocrystal solids
    Item type: Journal Article
    Bozyigit, D.; Wood, Vanessa (2014)
    Journal of Materials Chemistry C
Publications 1 - 10 of 38