Publications

2018

• Tin dioxide nanoparticles as catalyst precursors for plasma-assisted vapor–liquid–solid growth of silicon nanowires with well-controlled density
  
  • Dai Letian
  • Maurin Isabelle
  • Foldyna Martin
  • Alvarez José
  • Wang Weixi
  • Mohsin Hamza
  • Chen Wanghua
  • Kleider Jean-Paul
  • Maurice Jean-Luc
  • Gacoin Thierry
  • Roca I Cabarrocas Pere
  Nanotechnology, Institute of Physics, 2018, 29 (43). (10.1088/1361-6528/aad7db)
  DOI : 10.1088/1361-6528/aad7db
• Three-Dimensional Branched and Faceted Gold-Ruthenium Nanoparticles: Using Nanostructure to Improve Stability in Oxygen Evolution Electrocatalysis
  
  • Gloag Lucy
  • Benedetti Tania
  • Cheong Soshan
  • Li Yibing
  • Chan Xuan-Hao
  • Lacroix Lise-Marie
  • Chan Shery
  • Arenal Raul
  • Florea Ileana
  • Barron Hector
  • Barnard Amanda
  • Henning Anna
  • Zhao Chuan
  • Schuhmann Wolfgang
  • Gooding J. Justin
  • Tilley Richard
  Angewandte Chemie International Edition, Wiley-VCH Verlag, 2018, 57 (32), pp.10241-10245. Achieving stability with highly active Ru nanoparticles for electrocatalysis is a major challenge for the oxygen evolution reaction. As improved stability of Ru catalysts has been shown for bulk surfaces with low‐index facets, there is an opportunity to incorporate these stable facets into Ru nanoparticles. Now, a new solution synthesis is presented in which hexagonal close‐packed structured Ru is grown on Au to form nanoparticles with 3D branches. Exposing low‐index facets on these 3D branches creates stable reaction kinetics to achieve high activity and the highest stability observed for Ru nanoparticle oxygen evolution reaction catalysts. These design principles provide a synthetic strategy to achieve stable and active electrocatalysts.
• Investigation of porous anodic alumina templates formed by anodization of single-crystal aluminum substrates
  
  • Sacco Leandro
  • Florea Ileana
  • Châtelet Marc
  • Cojocaru Costel-Sorin
  Thin Solid Films, Elsevier, 2018, 660, pp.213-220. Ordered porous anodic alumina (PAA) templates are of great interest as they facilitate the future development of nanodevices. The present study focuses on the impact of substrates with different crystallographic orientations on the template's pore structure. Characteristics such as pore diameter, interpore distance, pore regularity, porosity, and circularity are calculated as a function of the anodization potential for three different Al crystal orientations. The presented experiments reveal that the different crystallographic orientations mainly impact the pore ordering, while other structural parameters, such as the pore diameter and interpore distance, are not significantly affected. (10.1016/j.tsf.2018.06.015)
  DOI : 10.1016/j.tsf.2018.06.015
• Assessment of High Sn Incorporation in Ge NanoWires Synthesized via In Plane Solid-Liquid-Solid Mechanism by In-Situ TEM
  
  • Moldovan Simona
  • Azrak Edy
  • Chen Wanghua
  • Gao Shiwen
  • Duguay Sébastien
  • Pareige Philippe
  • Roca I Cabarrocas Pere
  Microscopy and Microanalysis, Cambridge University Press, 2018, 24 (S1), pp.306-307. (10.1017/S1431927618002027)
  DOI : 10.1017/S1431927618002027
• Optical Study and Experimental Realization of Nanostructured Back Reflectors with Reduced Parasitic Losses for Silicon Thin Film Solar Cells
  
  • Li Zeyu
  • E Rusli
  • Chen Chenjin
  • Prakoso Ari
  • Foldyna Martin
  • Khoury Rasha
  • Bulkin Pavel
  • Wang Junkang
  • Chen Wanghua
  • Johnson Erik
  • Roca I Cabarrocas Pere
  Nanomaterials, MDPI, 2018, 8 (626). (10.3390/nano8080626)
  DOI : 10.3390/nano8080626
• Nanogenerators based on piezoelectric GaN nanowires grown by PA-MBE and MOCVD
  
  • Lu L.
  • Jamond N.
  • Eymery J.
  • Lefeuvre E.
  • Mancini L.
  • Larzeau L.
  • Madouri A.
  • Saket O.
  • Gogneau N.
  • Julien F.H.
  • Tchernycheva M.
  , 2019, pp.1-2. (10.1109/NANO.2018.8626416)
  DOI : 10.1109/NANO.2018.8626416
• Anharmonicity and Instabilities in Halide Perovskites for Last Generation Solar Cells
  
  • Marronnier Arthur
  , 2018. Hybrid halide perovskites (ABX3) have emerged over the past five years as absorber layers for novel high-efficiency low-cost solar cells combining the advantages of organic (molecule A) and inorganic (metal B, halogen X) materials. Very recently, fully inorganic perovskite quantum dots also shown promising efficiencies, making them a potentially stable and efficient alternative to their hybrid cousins.The aim of this PhD thesis is to study and better understand both the structural and thermodynamic instabilities of these halide perovskites, with a specific focus on purely inorganic CsPbI3 structures.We first use various ab-initio techniques, the majority of which are based on Density Functional Theory (DFT) and its linear-response approach (DFPT), to investigate the vibrational and electronic properties of the different phases of CsPbI3. While the black γ-phase, crucial for photovoltaic applications, is shown to behave harmonically around equilibrium, for the other three phases frozen phonon calculations reveal a Brillouin zone center double-well instability. We also show that avoiding the order-disorder entropy term arising from these double-well instabilities is key in order to prevent the formation of the yellow perovskitoid phase, and evidence a Rashba effect when using the symmetry breaking structures obtained through frozen phonon calculations. We then analyze the structural changes and the dynamical Rashba splitting along molecular dynamics trajectories in the light of our findings.In a second phase, we investigate the thermodynamical stability of hybrid perovskite MAPbI3. Our experimental ellipsometry-based study brings better understanding of the chemical decomposition of MAPbI3 into its two precursors, methylammonium and lead iodides, which we predicted using DFT stability diagram calculations and which we confirm by X-Ray diffraction. Last, we prove that hybrid perovskite structure MAPbI3 behaves more like inorganic compounds (high dielectric constant, low exciton binding energy) than like organic materials (low dielectric constant, high exciton binding energy).
• Low temperature plasma epitaxy of Silicon on III-V
  
  • Hamon Gwenaëlle
  • Vaissière Nicolas Vaissiere
  • Chen Wanghua
  • Alvarez J
  • Maurice Jean-Luc
  • Decobert Jean
  • Kleider Jean-Paul
  • Roca I Cabarrocas Pere Roca I Cabarrocas
  , 2018.
• Modélisation de la production photovoltaïque : Évaluation de l’incertitude à chaque étape de simulation
  
  • Migan-Dubois Anne
  • Badosa Jordi
  • Calderón Obaldía Fausto
  • Bourdin Vincent
  • Bonnassieux Yvan
  , 2018.
• Le solaire vu sous tous les angles au SIRTA
  
  • Badosa Jordi
  • Migan-Dubois Anne
  • Bourdin Vincent
  • Calderón Obaldía Fausto
  • Atlan Olivier
  • Pavlov Marko
  • Abdel Nour Christine
  • Bergamini Andrea
  • Ortega Pascal
  • Haeffelin Martial
  • Nassar Joaquim
  • Bonnassieux Yvan
  , 2018.
• Energy transition: electric vehicles, smartgrids and PV feedback of 19 months using of a small electric car
  
  • Bourdin Vincent
  • Badosa Jordi
  • Calderón Obaldía Fausto
  • Migan-Dubois Anne
  • Bonnassieux Yvan
  , 2018.
• Powder free PECVD epitaxial silicon by plasma pulsing or increasing the growth temperature
  
  • Chen Wanghua
  • Maurice Jean-Luc
  • Vanel Jean-Charles
  • Roca I Cabarrocas Pere
  Journal of Physics D: Applied Physics, IOP Publishing, 2018, 51 (23), pp.235203. (10.1088/1361-6463/aac1ea)
  DOI : 10.1088/1361-6463/aac1ea
• Anharmonicity and Disorder in the Black Phases of CsPbI3 used for Stable Inorganic Perovskite Solar Cells
  
  • Marronnier Arthur
  • Roma Guido
  • Boyer-Richard Soline
  • Pedesseau Laurent
  • Jancu Jean-Marc
  • Bonnassieux Yvan
  • Katan Claudine
  • Stoumpos Constantinos C
  • Kanatzidis Mercouri G
  • Even Jacky
  , 2018, pp.1715-1717. Hybrid perovskite materials have emerged over the past five years as absorber layers for new high-efficiency yet low-cost solar cells (PSCs) that combine the advantages of organic and inorganic semiconductors. Here, employing the linear response (DFPT) approach of Density Functional Theory (DFT) and frozen phonon calculations, we reveal strong anharmonic effects in the inorganic CsPbI3 perovskite. We also show through high resolution in-situ synchrotron XRD measurements that CsPbI3 can be undercooled below its transition temperature and temporarily maintained in its perovskite structure down to room temperature, stabilizing a metastable perovskite polytype (black γ-phase) crucial for photovoltaic applications. Among the four phases of CsPbI3, we found that this phase is the only one to behave harmonically around equilibrium. Last, we explain the Rashba effect in these materials as a consequence of the symmetry breaking induced by the double-well instabilities. (10.1109/PVSC.2018.8547769)
  DOI : 10.1109/PVSC.2018.8547769
• Low Bandgap Bistetracene-Based Organic Semiconductors Exhibiting Air Stability, High Aromaticity and Mobility
  
  • Frigoli Michel
  • Sbargoud Kamal
  • Mamada Masashi
  • Jousselin-Oba Tanguy
  • Takeda Y.
  • Tokito S.
  • Yassar A.
  • Marrot Jérôme
  , 2018.
• Electrochemical synthesis of polyaniline-exfoliated graphene composite films and their capacitance properties
  
  • Sayah Abdelfetteh
  • Habelhames Farid
  • Bahloul Ahmed
  • Nessark Belkacem
  • Bonnassieux Yvan
  • Tendelier Denis
  • El Jouad Mohamed
  Journal of Electroanalytical Chemistry, Elsevier, 2018, 818, pp.26-34. (10.1016/j.jelechem.2018.04.016)
  DOI : 10.1016/j.jelechem.2018.04.016
• Triphenylamine/oxadiazole hybrids differing by the substitution pattern: Influence on the electroluminescence properties of yellow and green emitting diodes
  
  • Lepeltier Marc
  • Sallenave Xavier
  • Tondelier Denis
  • Sini Gjergji
  • Goubard Fabrice
  • Gigmes Didier
  • Geffroy Bernard
  • Dumur Frédéric
  Synthetic Metals, Elsevier, 2018, 240, pp.21-29. In this study, three donor-acceptor-donor triphenylamine/oxadiazole hybrids differing by the substitution pattern were synthesized and characterized by means of experimental and density functional theory (DFT) methods. The new compounds were used as hosts for the design of yellow- and green organic light emitting diodes (OLEDs), exhibiting very different EL characteristics. The position of the triphenylamine substituents relative to the central phenyl-oxadiazole-phenyl core was found to greatly influence the EL performances. The results indicate that the increased internal torsion and the disrupture of the interring π-conjugation of the hosts impacts importantly the triplet energies andthe EL performance of OLEDs. OLEDs fabricated with the best host afforded an external quantum efficiency (EQE) of 17.1%, a current and power efficiency of 59.3 cd/A and 29.5 lm/W while doping the emissive layer at 10 wt% with the triplet emitter Ir(ppy)$_3$ (10.1016/j.synthmet.2018.03.008)
  DOI : 10.1016/j.synthmet.2018.03.008
• Triphenylamine/oxadiazole hybrids differing by the substitution pattern: Influence on the electroluminescence properties of yellow and green emitting diodes
  
  • Lepeltier Marc
  • Sallenave Xavier
  • Tondelier Denis
  • Sini Gjergji
  • Goubard Fabrice
  • Gigmes Didier
  • Geffroy Bernard
  • Dumur Frédéric
  Synthetic Metals, Elsevier, 2018, 240, pp.21-29. (10.1016/j.synthmet.2018.03.008)
  DOI : 10.1016/j.synthmet.2018.03.008
• Localized Plasmonic Resonances of Prolate Nanoparticles in a Symmetric Environment: Experimental Verification of the Accuracy of Numerical and Analytical Models
  
  • Kobylko Mathias
  • Coulon Pierre-Eugène
  • Slablab Abdallah
  • Fafin Alexandre
  • Cardin Julien
  • Dufour Christian
  • Losquin Arthur
  • Kociak Mathieu K
  • Monnet Isabelle
  • Mailly Dominique
  • Lafosse Xavier
  • Ulysse Christian
  • Garcia-Caurel Enric
  • Rizza Giancarlo
  Physical Review Applied, American Physical Society, 2018, 9 (6). We study the evolution of the surface-plasmon resonances of individual ion-beam-shaped prolate gold nanoparticles embedded in a dielectric SiO 2 environment by electron-energy-loss spectroscopy mapping in a scanning transmission electron microscope. The controlled symmetric dielectric environment obtained through the ion-beam-shaping method allows a direct quantitative comparison with numerical results obtained through simulations (auxiliary differential-equation finite-difference time-domain and boundary-element method) and with theoretical results obtained through analytical models (quasistatic model for prolate nanoellipsoids and waveguide model for infinite one-dimensional plasmonic waveguides), with which our experimental results are in very good agreement. We confirm the accuracy of state-of-the-art numerical tools and analytical theories that establish ion-beam shaping as a very promising method to design metal-dielectric nanocomposites with well-predicted optical properties, and with many possible applications in surface-enhanced Raman spectroscopy and second-harmonic generation, as well as in conventional applications of metamaterials like negative refraction, superimaging, and invisibility cloaking. (10.1103/PhysRevApplied.9.064038)
  DOI : 10.1103/PhysRevApplied.9.064038
• Evidence of halide ion migration in CH$_3$NH$_3$PbI$_3$(Cl) based perovskite solar cell and its effect on current-voltage hysteresis
  
  • Lee Heejae
  • Gaiaschi Sofia
  • Chapon Patrick
  • Marronnier Arthur
  • Tondelier Denis
  • Bonnassieux Yvan
  • Bourée Jean-Eric
  • Geffroy Bernard
  , 2018. Hybrid perovskite solar cells (PSCs) have rapidly emerged as a promising candidate for the next generation photovoltaics with power conversion efficiencies (PCEs) up to 22%. Low temperature solution processing, low cost raw material and relative insensitivity to intrinsic point defects are some of the attractive qualities of this emerging class of devices. But one of the major obstacles for the commercialization of PSCs lies in the long-term stability of the perovskite films subjected to different environmental conditions such as temperature, humidity and illumination. In this work, we focused on experimental evidence of halide ion migration in CH3NH3PbI3-xClx based solar cells and its effect on current-voltage hysteresis for which various mechanisms have been proposed. The inverted planar structure adopted for the PSCs was: glass/ITO/PEDOT:PSS/perovskite/PCBM/Ag. The perovskite thin films were deposited by 1-step spin-casting process and the organic PEDOT:PSS (hole-transporting layer) and PCBM (electron-transporting layer) layers were deposited by spin-coating process. Firstly, the PCE under 1 sun equivalent illumination reached 12.7% for the best cell of a series of 10 samples with an active area of 0.28 cm$^2$. The J-V hysteresis effect was small (less than 2.5%) between the reverse and the forward direction, consistent with the results reported in the literature. Secondly, using glow discharge optical emission spectrometry (GD-OES), a spectroscopic technique allowing direct determination of major and trace elements, we have shown that halide ions migrate inside the perovskite films under an applied bias during 2 minutes in both directions. Furthermore, no migration of lead and nitrogen ions was observed in the same time scale. Thirdly we observed the hysteresis of current-voltage characteristics under dark conditions (thus without any photo-generated carriers) versus voltage scanning rate and temperature. The activation energy value of 0.253 eV derived from the Nernst-Einstein relation above 264 K, for which the perovskite phase is tetragonal, indicates that the conduction is dominated by the ions (instead of electrons for conventional semiconductors) and furthermore confirms that the conduction is ascribed to the migration of anion vacancies, which is well known in the perovskite-type halides such as CsPbCl$_3$ or CsPbBr$_3$. These experiments prove that there is a direct link between halide ion migrations in CH$_3$NH$_3$PbI$_{3-x}$Cl$_x$ based perovskite thin films and current-voltage hysteresis.
• Uncertainty in the simulation of photovoltaic module performance related to outdoor parameters
  
  • Migan-Dubois Anne
  • Calderón Obaldía Fausto
  • Badosa Jordi
  • Bourdin Vincent
  • Bonnassieux Yvan
  , 2018.
• Anharmonicity and Disorder in the Black Phases of Cesium Lead Iodide used for Stable Inorganic Perovskite Solar Cells
  
  • Marronnier Arthur
  • Roma Guido
  • Boyer-Richard Soline
  • Pedesseau Laurent
  • Jancu Jean-Marc
  • Bonnassieux Yvan
  • Katan Claudine
  • Stoumpos Constantinos C
  • Kanatzidis Mercouri G
  • Even Jacky
  ACS Nano, American Chemical Society, 2018, 12 (4), pp.3477–3486. Hybrid organic-inorganic perovskites emerged as a new generation of absorber materials for high-efficiency low-cost solar cells in 2009. Very recently, fully inorganic perovskite quantum dots also led to promising efficiencies, making them a potentially stable and efficient alternative to their hybrid cousins. Currently, the record efficiency is obtained with CsPbI3 whose crystallographical characterization is still limited. Here we show through high resolution in-situ synchrotron XRD measurements that CsPbI3 can be undercooled below its transition temperature and temporarily maintained in its perovskite structure down to room temperature, stabilizing a metastable perovskite polytype (black γ-phase) crucial for photovoltaic applications. Our analysis of the structural phase transitions reveals a highly anisotropic evolution of the individual lattice parameters versus temperature. Structural, vibrational and electronic properties of all the experimentally observed black phases are further inspected based on several theoretical approaches. While the black γ-phase is shown to behave harmonically around equilibrium, for the tetragonal phase density functional theory reveals the same anharmonic behavior, with a Brillouin zone-centered double-well instability, as for the cubic phase. Using total energy and vibrational entropy calculations, we highlight the competition between all the low-temperature phases of CsPbI3 (γ, δ, β) and show that avoiding the order-disorder entropy term arising from double-well instabilities is key in order to prevent the formation of the yellow perovskitoid phase. A symmetry-based tight-binding model, validated by self-consistent GW calculations including spin-orbit coupling, affords further insight into their electronic properties, with evidence of Rashba effect for both cubic and tetragonal phases when using the symmetry breaking structures obtained through frozen phonon calculations. (10.1021/acsnano.8b00267)
  DOI : 10.1021/acsnano.8b00267
• Local open-circuit voltage characterization of thin-film radial junction PIN solar cells by Kelvin Probe Force Microscopy
  
  • Marchat Clément
  • Dai Letian
  • Misra Soumyadeep
  • Jaffré Alexandre
  • Alvarez J
  • Levtchenko Alexandra
  • Le Gall Sylvain
  • Connolly James P
  • Foldyna Martin
  • Kleider Jean-Paul
  • Roca I Cabarrocas Pere Roca I Cabarrocas
  , 2018.
• In situ spectroscopic ellipsometry study of low-temperature epitaxial silicon growth
  
  • Halagacka L.
  • Foldyna M.
  • Leal R.
  • Roca I Cabarrocas P.
  Photonics and Nanostructures - Fundamentals and Applications, Elsevier, 2018, 30, pp.73 - 77. (10.1016/j.photonics.2018.04.011)
  DOI : 10.1016/j.photonics.2018.04.011
• Nanostructured back reflectors produced using polystyrene assisted lithography for enhanced light trapping in silicon thin film solar cells
  
  • Li Zeyu
  • Rusli E.
  • Foldyna Martin
  • Wang Junkang
  • Chen Wanghua
  • Prakoso Ari Bimo
  • Lu Chenjin
  • Roca I Cabarrocas Pere
  Solar Energy, Elsevier, 2018, 167, pp.108 - 115. (10.1016/j.solener.2018.03.079)
  DOI : 10.1016/j.solener.2018.03.079
• Kinetic theory of two-temperature polyatomic plasmas
  
  • Orlac'H Jean-Maxime
  • Giovangigli Vincent
  • Novikova Tatiana
  • Roca Pere
  Physica A: Statistical Mechanics and its Applications, Elsevier, 2018, 494, pp.503--546. We investigate the kinetic theory of two-temperature plasmas for reactive polyatomic gas mixtures. The Knudsen number is taken proportional to the square root of the mass ratio between electrons and heavy-species, and thermal non-equilibrium between electrons and heavy species is allowed. The kinetic non-equilibrium framework also requires a weak coupling between electrons and internal energy modes of heavy species. The zeroth-order and first-order fluid equations are derived by using a generalized Chapman-Enskog method. Expressions for transport fluxes are obtained in terms of macroscopic variable gradients and the corresponding transport coefficients are expressed as bracket products of species perturbed distribution functions. The theory derived in this paper provides a consistent fluid model for non-thermal multicomponent plasmas. (10.1016/j.physa.2017.11.151)
  DOI : 10.1016/j.physa.2017.11.151