Publications

2019

Silicon Nanowire Solar Cells With µc-Si:H and a-Si:H Absorbers For Tandem Radial Junction Devices
- Dai Letian
- Foldyna Martin
- Maurin Isabelle
- Alvarez J
- Wang Weixi
- Ngo Eric
- Maurice Jean-Luc
- Gacoin Thierry
- Kleider Jean-Paul
- Roca I Cabarrocas Pere Roca I Cabarrocas
, 2019.
Effective resistance of random percolating networks of stick nanowires: Functional dependence on elementary physical parameters
- Benda Robert
- Cancès Eric
- Lebental Bérengère
Journal of Applied Physics, American Institute of Physics, 2019, 126 (4), pp.044306. We study by means of Monte-Carlo numerical simulations the resistance of two-dimensional random percolating networks of stick, widthless nanowires. We use the multi-nodal representation (MNR) 1 to model a nanowire network as a graph. We derive numerically from this model the expression of the total resistance as a function of all meaningful parameters, geometrical and physical , over a wide range of variation for each. We justify our choice of non-dimensional variables applying Buckingham π−theorem. The effective resistance of 2D random percolating networks of nanowires is found to write as R eq (ρ, Rc, Rm,w) = A N, L l * ρl * + B N, L l * Rc + C N, L l * Rm,w where N , L l * are the geometrical parameters (number of wires, aspect ratio of electrode separation over wire length) and ρ, Rc, Rm,w are the physical parameters (nanowire linear resistance per unit length, nanowire/nanowire contact resistance, metallic electrode/nanowire contact resistance). The dependence of the resistance on the geometry of the network, one the one hand, and on the physical parameters (values of the resistances), on the other hand, is thus clearly separated thanks to this expression, much simpler than the previously reported analytical expressions. (10.1063/1.5108575)
DOI : 10.1063/1.5108575
Advanced radial junction thin film photovoltaics and detectors built on standing silicon nanowires
- Zhang Ting
- Wang Junzhuan
- Yu Linwei
- Xu Jun (jim)
- Roca I Cabarrocas Pere
Nanotechnology, Institute of Physics, 2019, 30 (30), pp.302001. (10.1088/1361-6528/ab0e57)
DOI : 10.1088/1361-6528/ab0e57
Colour optimization of phosphor-converted flexible nitride nanowire white light emitting diodes
- Guan Nan
- Amador-Mendez Nuño
- Wang Junkang
- Das Subrata
- Kapoor Akanksha
- Julien François
- Gogneau Noelle
- Foldyna Martin
- Som Sudipta
- Eymery J.
- Durand Christophe
- Tchernycheva Maria
Journal of Physics: Photonics, IOP Science, 2019, 1 (3), pp.035003. (10.1088/2515-7647/ab2c84)
DOI : 10.1088/2515-7647/ab2c84
Effect of Halide Ion Migration on the Electrical Properties of Methylammonium Lead Tri-Iodide Perovskite Solar Cells
- Lee Heejae
- Gaiaschi Sofia
- Chapon Patrick
- Tondelier Denis
- Bourée Jean-Eric
- Bonnassieux Yvan
- Derycke Vincent
- Geffroy Bernard
Journal of Physical Chemistry C, American Chemical Society, 2019, 123, pp.17728-17734. Ionic migration in halide perovskite materials is now well recognized to affect the electrical properties of perovskite solar cells. Native point defects such as vacancies are considered as responsible for migration of ions. In order to interpret the unusual behavior of current–voltage curves in methylammonium lead tri-iodide perovskite (MAPI) solar cells, we combined two independent experiments: temperature-dependent conductivity measurements (213–363 K) under dark and glow discharge optical emission spectroscopy (GD-OES) under electrical bias conditions. From the film conductivity measurements, we observed two different conduction regimes: an ionic conduction regime at temperatures higher than 263 K, associated with an activation energy of 0.25 eV, and an electronic conduction regime below 263 K. At room temperature, both conductivities are around 10–7 S/cm. From GD-OES, we observed directly a reversible migration of iodide ions under positive or negative bias (minute time scale) at room temperature and deduced an iodide ion diffusion coefficient of 1.3 × 10–12 cm2·s–1 and a mobility of 5 × 10–11 cm2·V–1·s–1. (10.1021/acs.jpcc.9b04662)
DOI : 10.1021/acs.jpcc.9b04662
Synthesis and investigation of 7,7’ disubstituted Isoindigo for organic electronic applications
- Yassar Abderrahim
- Ren Shiwei
, 2019. The development of novel electron-deficient acceptor building blocks plays a vital role in conjugated materials for electronic applications. Incorporation of lactam moieties on conjugated backbones is one of the most important design concepts of acceptor units. Isoindigo (iI) is a lactam core fused with phenyl group, it is an excellent electron-accepting building block and recently it has become very popular in semiconductors for OPV applications. Isoindigo can be functionalized on different position. The electronic effects of substitution pattern (5,5’ vs. 6,6’) and substituent nature have been reported. The study showed that substitution patterns played significant roles on the photo-physical properties of molecular iI compounds. The 6,6’ substituted derivatives had more extended conjugation than the 5,5’ substituted derivatives because of the large contribution of electronic transition dipole moment in the axis aligned with the 6, 6’ carbons. However, little attention has been paid to the substitution at 4,4’ positions and 7,7’ positions, Figure 1. Figure 1: Structure of Isoindigo derivatives In this work, we report on the effect of the substituent at the 4,4’ and 7,7’-positions of the iI-core. Hence, we have developed a new method for the synthesis of various bromo-isatin and bromo oxindole derivatives. Extending the conjugation at the 7-position via Suzuki or Stille cross-coupling reaction yields to useful functionalized-isatin, as synthon for further transformation. Direct condensation of 7-bromoisatin and 7-bromo-oxindole in acetic acid afforded 7,7′-dibromo-iI. However, the large steric hindrance induced by the bromine atom at
Digital histology with Mueller microscopy: how to mitigate an impact of tissue cut thickness fluctuations
- Lee Hee Ryung
- Li Pengcheng
- Yoo Thomas Sang Hyuk
- Lotz Christian
- Groeber-Becker Florian Kai
- Dembski Sofia
- Garcia-Caurel Enric
- Ossikovski Razvigor
- Ma Hui
- Novikova Tatiana
Journal of Biomedical Optics, Society of Photo-optical Instrumentation Engineers, 2019, 24 (07), pp.1. (10.1117/1.jbo.24.7.076004)
DOI : 10.1117/1.jbo.24.7.076004
Digital histology with Mueller microscopy: how to mitigate an impact of tissue cut thickness fluctuations
- Lee Hee Ryung
- Li Pengcheng
- Yoo Thomas Sang Hyuk
- Lotz Christian
- Groeber-Becker Florian Kai
- Dembski Sofia
- Garcia-Caurel Enric
- Ossikovski Razvigor
- Ma Hui
- Novikova Tatiana
Journal of Biomedical Optics, Society of Photo-optical Instrumentation Engineers, 2019, 24 (07), pp.1. (10.1117/1.jbo.24.7.076004)
DOI : 10.1117/1.jbo.24.7.076004
Mueller microscopy of full thickness skin models combined with image segmentation
- Lee Hee Ryung
- Lotz Christian
- Groeber-Becker Florian Kai
- Dembski Sofia
- Garcia-Caurel Enric
- Ossikovski Razvigor
- Novikova Tatiana
, 2019, pp.42. (10.1117/12.2526626)
DOI : 10.1117/12.2526626
Diagnostics of high grade cervical intraepithelial neoplasia with Mueller matrix polarimetry
- Kupinski Meredith
- Boffety Matthieu
- Ossikovski Razvigor
- Pierangelo Angelo
- Rehbinder Jean
- Vizet Jérémy
- Goudail François
- Novikova Tatiana
, 2019, pp.8. (10.1117/12.2527117)
DOI : 10.1117/12.2527117
Tissue polarimetric study I: In search of reference parameters and depolarizing Mueller matrix model of ex vivo colon samples
- Ivanov Deyan
- Ossikovski Razvigor
- Novikova Tatiana
- Li Pengcheng
- Borisova Ekaterina
- Genova Tsanislava
- Nedelchev Lian
- Nazarova Dimana
, 2019, pp.37. (10.1117/12.2526594)
DOI : 10.1117/12.2526594
Functionalized TiO 2 Nanorods on a Microcantilever for the Detection of Organophosphorus Chemical Agents in Air
- Biapo Urelle
- Ghisolfi Alessio
- Gerer Geoffrey
- Spitzer Denis
- Keller Valérie
- Cottineau Thomas
ACS Applied Materials & Interfaces, Washington, D.C. : American Chemical Society, 2019, 11 (38), pp.35122-35131. We report the fabrication of nanostructured microcantilevers employed as sensors for the detection of organophosphorus (OPs) vapors. These micromechanical sensors are prepared using a two-step procedure first optimized on a silicon wafer. TiO 2 one-dimensional nanostructures are synthesized at a silicon surface by a solvothermal method and then grafted with bifunctional molecules having an oxime group known for its strong affinity with organophosphorus compounds. The loading of oxime molecules grafted on the different nanostructured surfaces was quantified by UV spectroscopy. It has been found that a wafer covered by vertically aligned rutile TiO 2 nanorods (NRs), with an average length and width of 9.5 μm and 14.7 nm, respectively, provides an oxime function density of 360 nmol cm −2. The optimized TiO 2 nanorod synthesis was successfully reproduced on the cantilevers, leading to a homogeneous and reproducible TiO 2 NR film with the desired morphology. Thereafter, oxime molecules have been successfully grafted on the nanostructured cantilevers. Detection tests were performed in a dynamic mode by exposing the microcantilevers to dimethyl methylphosphonate (a model compound of toxic OPs agents) and following the shift of the resonant frequency. The nanostructure and the presence of the molecules on a TiO 2 NR surface both improve the response of the sensors. A detection limit of 2.25 ppm can be reached with this type of sensor. (10.1021/acsami.9b11504)
DOI : 10.1021/acsami.9b11504
Eigenvalue-based depolarization metric spaces for Mueller matrices
- Ossikovski Razvigor
- Vizet Jérémy
Journal of the Optical Society of America. A Optics, Image Science, and Vision, Optical Society of America, 2019, 36 (7), pp.1173. (10.1364/JOSAA.36.001173)
DOI : 10.1364/JOSAA.36.001173
Meandering growth of in-plane silicon nanowire springs
- Sun Ying
- Dong Taige
- Wang Junzhuan
- Xu Jun (jim)
- Chen Kunji
- Roca I Cabarrocas Pere
- Yu Linwei
Applied Physics Letters, American Institute of Physics, 2019, 114 (23), pp.233103. (10.1063/1.5097429)
DOI : 10.1063/1.5097429
Structural Robustness for Deep Learning Architectures
- Lassance Carlos
- Gripon Vincent
- Tang Jian
- Ortega Antonio
, 2019, pp.125-129. (10.1109/DSW.2019.8755564)
DOI : 10.1109/DSW.2019.8755564
Introducing Graph Smoothness Loss for Training Deep Learning Architectures
- Bontonou Myriam
- Lassance Carlos
- Hacene Ghouthi Boukli
- Gripon Vincent
- Tang Jian
- Ortega Antonio
, 2019, pp.160-164. (10.1109/DSW.2019.8755559)
DOI : 10.1109/DSW.2019.8755559
Excellent Semiconductors Based on Tetracenotetracene and Pentacenopentacene: From Stable Closed-Shell to Singlet Open-Shell
- Jousselin-Oba Tanguy
- Mamada Masashi
- Marrot Jérôme
- Maignan Antoine
- Adachi Chihaya
- Yassar Abderrahim
- Frigoli Michel
Journal of the American Chemical Society, American Chemical Society, 2019, 141 (23), pp.9373-9381. Designing stable open-shell organic materials through the modifications of the π-topology of molecular organic semiconductors have attracted recently considerable attention. However, their uses as an active layer in organic field-effect transistors (OFETs) are very limited and the obtained hole and electron charge mobilities are around 10 −3 cm 2 V −1 s −1. Herein, we disclosed the synthesis of two materials so-called tetraceno-tetracene (TT) and pentacenopentacene (PP) which have low band gap of 1.79 and 1.42 eV, respectively. Their ground state natures have been investigated by different experiments including steady state absorption, electron spin resonance, superconducting quantum interfering device (SQUID) and variable temperature NMR along with DFT calculations. TT and PP have closed-shell and singlet open-shell structures in their ground state, respectively , and possess high stability. Their biradical characteristics were found to be 0.50 and 0.64. The origin of the open-shell character of PP is related to the concomitant opening of two tetracenes with the recovering of two extra aromatic sextets and a small HOMO-LUMO energy gap (gap < 1.5 eV). Thanks to the high stability, thin film OFET devices could be fabricated. In TG-BC configuration PP shows remarkably high hole mobility of 1.4 cm 2 V −1 s −1 while TT exhibits a hole mobility of 0.77 cm 2 V −1 s −1. In configuration of BG-TC, ambipolar behaviors for both were obtained with hole and electron mobilities of 0.21 and 0.01 cm 2 V −1 s −1 for PP and 0.14 and 0.006 cm 2 V −1 s −1 for TT. (10.1021/jacs.9b03488)
DOI : 10.1021/jacs.9b03488
Silicon nanowire solar cells with μc-Si:H absorbers for radial tandem devices
- Dai Letian
- Foldyna Martin
- Maurin Isabelle
- Alvarez J
- Wang Weixi
- Ngo Eric
- Kleider Jean-Paul
- Maurice Jean-Luc
- Gacoin Thierry
- Roca I Cabarrocas Pere Roca I Cabarrocas
, 2019.
Impact of PECVD poly-Si on Tunnel Oxide for Passivating Contacts
- Desthieux Anatole
- Posada Jorge
- Grand Pierre-Philippe
- Broussillou Cédric
- Bazer-Bachi Barbara
- Goaer Gilles
- Messou Davina
- Bouttemy Muriel
- Drahi Etienne
- Cabarrocas Pere Roca I
, 2019.
Hydrogen evolution in hydrogenated microcrystalline silicon carbide thin films
- Nemmour Soumia
- Djoumi Siham
- Kail Fatiha
- Roura-Grabulosa Pere
- Roca I Cabarrocas Pere
- Chahed Larbi
Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics, AVS through the American Institute of Physics, 2019, 37 (3), pp.031218. (10.1116/1.5090174)
DOI : 10.1116/1.5090174
Impact of charged species transport coefficients on self-bias voltage in an electrically asymmetric RF discharge
- Orlac'H Jean-Maxime
- Novikova Tatiana
- Giovangigli Vincent
- Johnson Erik
- Roca Pere
Plasma Sources Science and Technology, IOP Publishing, 2019, 28 (5), pp.055003. In this paper, we use a fluid model to simulate the excitation of a hydrogen radio-frequency discharge, and employ tailored voltage waveforms to assess the effect of charged species transport properties. Results of the fluid simulation are compared with experimental data and previous results obtained with a hybrid model. Several expressions for electron and ion transport coefficients are compared, and their impact on the self-bias potential is studied. The self-bias is shown to be insensitive to the choice of electron transport coefficients, while remarkably sensitive to variations in ion mobility. Besides, our results show that fluid models can be competitive with hybrid models, provided self-consistent ion transport models and rate constants are used. (10.1088/1361-6595/ab067d)
DOI : 10.1088/1361-6595/ab067d
Impact of charged species transport coefficients on self-bias voltage in an electrically asymmetric RF discharge
- Orlac’h Jean-Maxime
- Novikova Tatiana
- Giovangigli Vincent
- Johnson Erik
- Cabarrocas Pere Roca I
Plasma Sources Science and Technology, IOP Publishing, 2019, 28 (5), pp.055003. (10.1088/1361-6595/ab067d)
DOI : 10.1088/1361-6595/ab067d
Influence of p- and n-type doping gases on nanoparticle formation in SiH 4 /H 2 radiofrequency plasma discharges used for polymorphous silicon thin film deposition
- Kharchenko A.
- Ouaras K.
- Suendo V.
- Ebothe J.
- Roca I Cabarrocas P.
Journal of Applied Physics, American Institute of Physics, 2019, 125 (16), pp.163307. (10.1063/1.5090769)
DOI : 10.1063/1.5090769
Structural and theoretical studies of Black Phases of CsPbI3: influence of the anharmonicity
- Pedesseau Laurent
- Marronnier Arthur
- Roma Guido
- Boyer-Richard S.
- Jancu Jean-Marc
- Bonnassieux Yvan
- Katan Claudine
- Stoumpos Constantinos C
- Kanatzidis Mercouri G
- Even Jacky
, 2019.
Phosphahelicenes: from chiroptical and photophysical properties to OLED applications
- Yavari Keihann
- Delaunay Wylliam
- de Rycke Nicolas
- Reynaldo Thibault
- Aillard Paul
- Srebro-Hooper Monika
- Chang Victoria Y.
- Muller Gilles
- Tondelier Denis
- Geffroy Bernard
- Voituriez Arnaud
- Marinetti Angela
- Hissler Muriel
- Crassous Jeanne
Chemistry - A European Journal, Wiley-VCH Verlag, 2019, 25 (20), pp.5303-5310. Herein, the experimental physicochemical and chiroptical properties of a series of phosphahelicenes are reported, focusing on their UV/Vis absorption, luminescence, electronic circular dichroism, optical rotations, and circularly polarized luminescence. Furthermore, detailed analysis of absorption and ECD spectra performed with the help of quantum-chemical calculations allowed us to highlight general features of these helicenic phosphines. Finally, due to well-suited electrochemical properties and thermal stability, the systems were successfully used as emitters in organic light-emitting diodes. (10.1002/chem.201806140)
DOI : 10.1002/chem.201806140

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