Publications

2021

• Single-Crystalline Body Centered FeCo Nano-Octopods: from One-Pot Chemical Growth to Complex 3D Magnetic Configuration
  
  • Garnero Cyril
  • Pierrot Alexandre
  • Gatel Christophe
  • Marcelot Cécile
  • Arenal Raul
  • Florea Ileana
  • Bernand-Mantel Anne
  • Soulantica Katerina
  • Poveda Patrick
  • Chaudret Bruno
  • Blon Thomas
  • Lacroix Lise-Marie
  Nano Letters, American Chemical Society, 2021, 21 (8), pp.3664-3670. Single crystalline magnetic FeCo nanostars were prepared using an organometallic approach under mild conditions. The fine-tuning of the experimental conditions allowed the direct synthesis of these nano-octopods with body-centered cubic (bcc) structure through a one-pot reaction, contrarily to the seed-mediated growth classically used. The FeCo nanostars consist of 8 tetrahedrons exposing {311} facets, as revealed by high resolution transmission electron microscopy (HRTEM) imaging and electron tomography (ET), and exhibit a high magnetization comparable with the bulk one (Ms = 235 A·m2·kg–1). Complex 3D spin configurations resulting from the competition between dipolar and exchange interactions are revealed by electron holography. This spin structures are stabilized by the high aspect ratio tetrahedral branches of the nanostars, as confirmed by micromagnetic simulations. This illustrates how magnetic properties can be significantly tuned by nanoscale shape control. (10.1021/acs.nanolett.1c01087)
  DOI : 10.1021/acs.nanolett.1c01087
• Quinolinophenothiazine as electron rich fragment for RGB single-layer phosphorescent organic light-emitting diodes
  
  • Lucas Fabien
  • Tondelier Denis
  • Geffroy Bernard
  • Heiser Thomas
  • Ibraikulov Olzhas
  • Quinton Cassandre
  • Brouillac Clement
  • Leclerc Nicolas
  • Rault-Berthelot Joëlle
  • Poriel Cyril
  Materials Chemistry Frontiers, Royal Society of Chemistry, 2021, 5 (22), pp.8066-8077. The quinolinophenothiazine (QPTZ) fragment is a phenylacridine bridged by a sulphur atom. Despite appealing properties induced by this bridging (e.g. strong electron rich character), this fragment remains almost unexplored to date in organic electronics. Based on this QPTZ fragment, we report herein a high efficiency host for the new generation of simplified Phosphorescent Organic Light-Emitting Diodes so called Single-Layer (SL-PhOLEDs). This host material is constructed on the association of an electron rich fragment (QPTZ), and an electron-deficient fragment (2,7-bis (diphenylphosphineoxide)-fluorene). This molecule displays all the necessary properties to be used in universal SL-PhOLEDs. Red, green and blue SL-PhOLEDs were successfully fabricated and yielded an average external quantum efficiency of ca 10%. High luminances of ca 10000 cd/m$^2$ for red and blue devices and 40000 cd/m$^2$ for green devices were obtained. These luminances are higher than the best reported to date with structurally related analogues and highlight the strong interest of the QPTZ fragment in such devices. Thanks to its high HOMO level, the QPTZ unit also allows to decrease the threshold voltage, which is a key characteristic in the OLED technology. This work shows the potential of the QPTZ fragment in the design of host materials for high performance single-layer PhOLEDs. (10.1039/D1QM01138C)
  DOI : 10.1039/D1QM01138C
• Impact of PECVD-prepared interfacial Si and SiGe layers on epitaxial Si layers grown by PECVD (200 °C) and APCVD (1130 °C)
  
  • An Junyang
  • Maurice Jean-Luc
  • Depauw Valérie
  • Roca I Cabarrocas Pere
  • Chen Wanghua
  Applied Surface Science, Elsevier, 2021, 546, pp.149056. The homoepitaxy of Si is particularly interesting for the purpose of kerfless wafer production, for example in the photovoltaic domain. Substrate surface engineering is a key step prior to epitaxial growth, which will affect the quality of the epitaxial layer and its detachment for layer transfer. In this work, we propose two plasma-based surface engineering methods including the deposition of a bilayer homoepitaxial interface and a SiGe heteroepitaxial interface. Their impact on the crystalline quality of epitaxial Si layers grown both by plasma enhanced chemical vapor deposition (PECVD) at 200 °C and by atmospheric pressure chemical vapor deposition (APCVD) at 1130 °C are explored. Stacking faults are observed in epitaxial Si layers with an ultra-thin epitaxial Si interface layer. For surface engineering method based on the 2 addition of an interfacial heteroepitaxial SiGe layer, higher interfacial hydrogen content and better bulk epitaxial Si quality are observed in comparison with interfacial homoepitaxial Si layer. (10.1016/j.apsusc.2021.149056)
  DOI : 10.1016/j.apsusc.2021.149056
• Insight into the formation and stability of solid electrolyte interphase (SEI) for nanostructured siliconbased anode electrodes used in Li-ion batteries
  
  • Ezzedine Mariam
  • Zamfir Mihai-Robert
  • Jardali Fatme
  • Leveau Lucie
  • Caristan Eleonor
  • Ersen Ovidiu
  • Cojocaru Costel Sorin
  • Florea Ileana
  ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2021, 13 (21), pp.24734-24746. Silicon-based anode fabrication with nanoscale structuration improves the energy density and life cycle of Li-ion batteries. As-synthesized silicon (Si) nanowires (NWs) or nanoparticles (NPs) directly on the current collector represent a credible alternative to conventional graphite anodes. However, the operating potentials of these electrodes are below the electrochemical stability window of all electrolytes used in commercial Li-ion systems. During the first charging phase of the cell, partial decomposition of the electrolyte takes place, which leads to the formation of a layer at the surface of the electrode, called solid electrolyte interphase (SEI). A stable and continuous SEI layer formation is a critical factor to achieve reliable lifetime stability of the battery. Once formed, the SEI acts as a passivation layer that minimizes further degradation of the electrolyte during cycling, while allowing lithium-ion diffusion with their subsequent insertion into the active material and ensuring reversible operation of the electrode. However, one of the major issues requiring deeper investigation is the assessment of the morphological extension of the SEI layer into the active material, which is one of the main parameters affecting the anode performances. In the present study, we use electron tomography with a low electron dose to retrieve three-dimensional information on the SEI layer formation and its stability around SiNWs and SiNPs. The possible mechanisms of SEI evolution could be inferred from the interpretation and analysis of the reconstructed volumes. Significant volume variations in the SiNW and an inhomogeneous distribution of the SEI layer around the NWs are observed during cycling and provide insights into the potential mechanism leading to the generally reported SiNW anode capacity fading. By contrast, analysis of the reconstructed SiNPs’ volume for a sample undergoing one lithiation–delithiation cycle shows that the SEI remains homogeneously distributed around the NPs that retain their spherical morphology and points to the potential benefit of such nanoscale Si anode materials to improve their cycling lifetime. (10.1021/acsami.1c03302)
  DOI : 10.1021/acsami.1c03302
• III-V MULTIJUNCTION SOLAR CELLS ON ULTRATHIN GE|SI VIRTUAL SUBSTRATES GROWN AT LOW TEMPERATURE BY RF-PECVD
  
  • García Iván
  • Ghosh Monalisa
  • Orejuela Víctor
  • Roca I Cabarrocas Pere
  • Rey-Stolle Ignacio
  , 2021. The application of Ge|Si virtual substrates with an ultrathin Ge layer to the development of high efficiency III-V solar cells is analyzed. The potential to achieve high efficiencies in GaInP/GaInAs/Si triple-junction cells, which is affected by the optical absorption in the Ge layer, is theoretically demonstrated under realistic scenarios of Ge|Si substrate characteristics and III-V cell configurations. The first dual-junction GaInAs/Ge|Si III-V cells fabricated on these substrates demonstrate the concept with functional devices and show the route to high efficiency implementations by using appropriate Si substrates and optimized Ge deposition.
• Origin of area selective plasma enhanced chemical vapor deposition of microcrystalline silicon
  
  • Akiki Ghewa
  • Frégnaux Mathieu
  • Florea Ileana
  • Bulkin Pavel
  • Daineka Dmitri
  • Filonovich Sergej
  • Bouttemy Muriel
  • Johnson Erik
  Journal of Vacuum Science & Technology A, American Vacuum Society, 2021, 39 (1), pp.013201. Plasma Enhanced Chemical Vapor Deposition of silicon from SiF4/H2/Ar gas mixture is observed on a SiOxNy surface, while under the same plasma conditions, silicon films do not grow on AlOx nor Al surfaces. Transmission electron microscopy confirms that the silicon deposited on SiOxNy has a microcrystalline structure. After the plasma process, fluorine is detected in abundance on the AlOx surface by X-ray photoelectron spectroscopy and energy dispersive X-ray chemical analyses. This suggests that Al-F bonds are formed on this surface, blocking any deposition of silicon on it. In-situ ellipsometry studies show that deposition can be initiated on AlOx surfaces by increasing the temperature of the electrodes or increasing the RF plasma power, leading to a loss of selectivity. (10.1116/6.0000653)
  DOI : 10.1116/6.0000653
• A highly efficient solution and solid state ESIPT fluorophore and its OLEDs application
  
  • Yu Pei
  • Trannoy Virgile
  • Léaustic Anne
  • Gadan Sophie
  • Guillot Régis
  • Allain Clémence
  • Clavier Gilles
  • Mazerat Sandra
  • Geffroy Bernard
  New Journal of Chemistry, Royal Society of Chemistry [1987-....], 2021, 45, pp.3014-3021. We present herein the synthesis and the photophysics of 2,2’-bipyridine-3,3’-diol-5,5’-dicarboxylic acid ethyl ester (BP(OH)$_2$DCEt$_2$), an excited state intramolecular proton tranfer (ESIPT)-based fluorophore featuring two identical intramolecular hydrogen bonds. BP(OH)$_2$DCEt$_2$ emits efficiently not only in solution, including protic solvents ($\lambda _{em}$ = 521 nm, $\Phi$$_f$ = 40 to 75%), but also in crystalline state ($\lambda _{em}$ = 530 nm, $\Phi$$_f$ = 51%). In addition, its saponified form (Na2BP(OH)2DC) is highly fluorescent in water ($\lambda _{em}$ = 490 nm, $\Phi$$_f$ = 51%). Finally, the good electroluminescence performance of BP(OH)$_2$DCEt$_2$ is also demonstrated in an OLED device. (10.1039/D0NJ05600F)
  DOI : 10.1039/D0NJ05600F
• Polarimetric visualization of healthy brain fiber tracts under adverse conditions: ex vivo studies
  
  • Rodríguez-Núñez Omar
  • Schucht Philippe
  • Hewer Ekkehard
  • Novikova Tatiana
  • Pierangelo Angelo
  Biomedical optics express, Optical Society of America - OSA Publishing, 2021, 12 (10), pp.6674. We suggest using the wide-field imaging Mueller polarimetry to contrast optically anisotropic fiber tracts of healthy brain white matter for the detection of brain tumor borders during neurosurgery. Our prior studies demonstrate that this polarimetric imaging modality detects correctly the in-plane orientation of brain white matter fiber tracts of a flat formalin-fixed thick brain specimen in reflection geometry [ IEEE Trans. Med. Imaging 39 , 4376 ( 2020 ) 10.1109/TMI.2020.3018439 ]. Here we present the results of ex vivo polarimetric studies of large cross-sections of fresh calf brain in reflection geometry with a special focus on the impact of the adverse measurement conditions (e.g. complex surface topography, presence of blood, etc.) on the quality of polarimetric images and the detection performance of white matter fiber tracts and their in-plane orientation. (10.1364/BOE.439754)
  DOI : 10.1364/BOE.439754
• Highly Uniform, Straightforward, Controllable Fabrication of Copper Nano-Objects via Artificial Nucleation-Assisted Electrodeposition
  
  • Lim Joonwon
  • Kim Ki-Hwan
  • Cojocaru Costel Sorin
  Journal of Electroanalytical Chemistry, Elsevier, 2021. Electrochemical synthetic route to sophisticated nano-objects has been considered as a promising and reliable strategy for diverse purpose in a wide range of applications. Especially, electrodeposition using nanoporous templates has attracted intensive research interests due to the potential for realizing diverse nanostructures and delicate composition control of the resulting fabricated materials. Unfortunately, the electrochemically filling of nanomaterials into nanoporous templates are still suffering from unexpected non-uniform formation of nanoobjects, originating from random nucleation in each nanopore and overgrowth from only a few nanopores. Here, we present a highly uniform, straightforward and controllable fabrication of Cu nano-objects via artificial nucleation-assisted electrodeposition principle using nanoporous AAO templates. Pre-electrodeposited Ni nanoparticles at the bottom of the nanopores of AAO successfully plays a role as a nucleus at the early stage of Cu electrodeposition process. The artificial nuclei enable highly uniform and stable Cu electrodeposition inside the nanopores of AAO templates by effectively suppressing the random overgrowth of Cu. Taking advantage of the stable electrodepositing behavior, we demonstrate precise control of the geometry of Cu nano-objects, uniformly dispersed over whole surfaces of substrates. (10.1016/j.jelechem.2021.115594)
  DOI : 10.1016/j.jelechem.2021.115594
• Raw and processed data used in non-covalent functionalization of single walled carbon nanotubes with Co-porphyrin and Co-phthalocyanine and its effect on field-effect transistor characteristics
  
  • Bouanis Fatima Z
  • Bensifia Mohamed
  • Florea Ileana
  • Mahouche-Chergui Samia
  • Carbonnier Benjamin
  • Grande Daniel
  • Léonard Céline
  • Yassar Abderrahim
  • Pribat Didier
  Data in Brief, Elsevier, 2021, 38, pp.107366. This scientific data article is related to the research work entitled “Non-Covalent functionalization of Single Walled Carbon Nanotubes with Fe-/Co-porphyrin and Co-phthalocyanine for Field-Effect Transistor Applications” published in “Organic electronics” (10.1016/j.orgel.2021.106212). In this work, we present the data of morphological, chemical and structural analyses of non-covalent functionalization of SWNTs with Co-porphyrin and Co-phthalocyanine. The analyses were performed by Raman spectroscopy, transmission electron microscopy as well as the electrical characterization of CNTFETs. This work is completed by the data of the theoretical calculations performed using Density Functional Theory (DFT). (10.1016/j.dib.2021.107366)
  DOI : 10.1016/j.dib.2021.107366
• Determination of optical constants from Martian analog materials using a spectro-polarimetric technique
  
  • Alemanno G.
  • Garcia-Caurel E.
  • Carter J.
  • Poulet François
  • Brunetto R.
  • Aléon-Toppani Alice
  • Urso R.G.
  • Mivumbi O.
  • Boukari Claire
  • Godard Vincent
  • Borondics Ferenc
  Planetary and Space Science, Elsevier, 2021, 195, pp.105138. (10.1016/j.pss.2020.105138)
  DOI : 10.1016/j.pss.2020.105138
• Polarization and Orbital Angular Momentum of Light in Biomedical Applications: feature issue introduction
  
  • Meglinski Igor
  • Novikova Tatiana
  • Dholakia Kishan
  Biomedical optics express, Optical Society of America - OSA Publishing, 2021, 12 (10), pp.6255. In the last decade, consistent and successful innovations have been achieved in the field of lasers and optics, collectively known as ‘photonics’, founding new applications in biomedicine, including clinical biopsy. Non-invasive photonics-based diagnostic modalities are rapidly expanding, and with their exponential improvement, there is a great potential to develop practical instrumentation for automatic detection and identification of different types and/or sub-types of diseases at a very early stage. While using conventional light for the studies of different properties of objects in materials science, astrophysics and biomedicine already has a long history, the interaction of polarized light and optical angular momentum with turbid tissue-like scattering media has not yet been ultimately explored. Since recently this research area became a hot topic. This feature issue is a first attempt to summarize the recognitions achieved in this emerging research field of polarized light and optical angular momentum for practical biomedical applications during the last years. (10.1364/BOE.442828)
  DOI : 10.1364/BOE.442828
• Synthesis, Aromaticity and Application of peri-PentacenoPentacene: Localized Representation of Benzenoid Aromatic Compounds
  
  • Jousselin‐oba Tanguy
  • Mamada Masashi
  • Wright Karen
  • Marrot Jérome
  • Adachi Chihaya
  • Yassar Abderrahim
  • Frigoli Michel
  Angewandte Chemie International Edition, Wiley-VCH Verlag, 2021. We report the synthesis and optoelectronic properties of TIPS-peri-pentacenopentacene (TIPS-PPP), a vertical extension of TIPS-pentacene (TIPS-PEN) and a low-band-gap material with remarkable stability. We found the synthetic conditions to avoid the competition between 1,2- and 1,4-addition of lithium acetylide on the large aromatic dione. The high stability of TIPS-PPP is due to the peri-fusion which increases the aromaticity by generating two localized aromatic sextets that are flanked with 2 diene fragments, similar to two fused-anthracenes. Like TIPS-PEN, TIPS-PPP shows the archetypal 2D brickwall motif in crystals with a larger transfer integral and smaller reorganization energy. The high mobility of up to 1 cm2 V−1 s−1 was obtained in an organic field-effect transistor fabricated by a wet process. Also, TIPS-PPP was used as a near-infrared (NIR) emitter for NIR organic-light-emitting-diode devices resulting in a high external quantum efficiency at 800 nm. (10.1002/anie.202112794)
  DOI : 10.1002/anie.202112794
• Shedding the Polarized Light on Biological Tissues
  
  • I. Meglinski
  • L. Trifonyuk
  • V. Bachinsky
  • O. Vanchulyak
  • B. Bodnar
  • M. Sidor
  • O. Dubolazov
  • A. Ushenko
  • Y. Ushenko
  • I. V. Soltys
  • A. Bykov
  • B. Hogan
  • T. Novikova
  , 2021.
• Experimental observation of carousel-like phason flips in the decagonal quasicrystal Al 60 Cr 20 Fe 10 Si 10
  
  • He Zhanbing
  • Maurice Jean-Luc
  • Ma Haikun
  • Li Hua
  • Zhang Tiantian
  • Wang Yanguo
  • Ma Xiuliang
  • Steurer Walter
  Acta Crystallographica Section A : Foundations and Advances [2014-...], International Union of Crystallography, 2021, 77 (5). Quasicrystals have special crystal structures with long-range order, but without translational symmetry. Unexpectedly, carousel-like successive flippings of groups of atoms inside the ∼2 nm decagonal structural subunits of the decagonal quasicrystal Al 60 Cr 20 Fe 10 Si 10 were directly observed using in situ high-temperature high-resolution transmission electron microscopy imaging. The observed directionally successive phason flips occur mainly clockwise and occasionally anticlockwise. The origin of these directional phason flips is analyzed and discussed. (10.1107/S2053273321007518)
  DOI : 10.1107/S2053273321007518