Publications

2025

• Amorphous GaN matrix embedded nanocrystals exhibiting bulk band-gap luminescence
  
  • Srinivasan Lakshman
  • Maurice Jean-Luc
  • Pirotta Stefano
  • Collin Stéphane
  • Johnson Erik
  • Roca i Cabarrocas Pere
  • Ouaras Karim
  APL Materials, AIP Publishing, 2025, 13 (6). <div><p>This work reports on room temperature sputtering growth of GaN thin films, exhibiting band-edge luminescence without thermal annealing or post-deposition processing. Particularly, we investigate and correlate their luminescence spectra with their structural properties (amorphous or polycrystalline phases), the presence of defects, and the grain features by combining cathodoluminescence and HR-TEM characterizations. The working pressure and Ar/N2 flow ratio are found to have a profound effect on both the structural and optical properties of the films. Notably, the only film with band-edge luminescence is grown at the highest investigated pressure (13.3 Pa) and 40%N2 concentration and exhibits single-grained crystallites of small sizes (~5nm). Moreover, this polycrystalline film has an almost equal fraction of amorphous and crystalline phases. This suggests that the presence of smooth and nanometer-sized crystals in an amorphous matrix (inducing grain surface passivation) could be a synergetic combination to achieve luminescent films grown at room temperature.</p></div> (10.1063/5.0253319)
  DOI : 10.1063/5.0253319
• Amorphous GaN matrix embedded nanocrystals exhibiting bulk bandgap luminescence
  
  • Srinivasan Lakshman
  • Maurice Jean-Luc
  • Pirotta Stefano
  • Collin Stéphane
  • Johnson Erik
  • Roca i Cabarrocas Pere
  • Ouaras Karim
  APL Materials, AIP Publishing, 2025, 13 (6). This work reports on the room temperature sputtering growth of gallium nitride thin films, exhibiting band edge luminescence without thermal annealing or post-deposition processing. In particular, we investigate and correlate their luminescence spectra with their structural properties (amorphous or polycrystalline phases), the presence of defects, and the grain features by combining cathodoluminescence and HR-TEM characterizations. The working pressure and Ar/N2 flow ratio are found to have a profound effect on both the structural and optical properties of the films. Notably, the only film with band edge luminescence is grown at the highest investigated pressure (13.3 Pa) and 40% N2 concentration and exhibits single-grained crystallites of small sizes (∼5 nm). Moreover, this polycrystalline film has an almost equal fraction of amorphous and crystalline phases. This suggests that the presence of smooth and nanometer-sized crystals in an amorphous matrix (inducing grain surface passivation) could be a synergetic combination to achieve luminescent films grown at room temperature. (10.1063/5.0253319)
  DOI : 10.1063/5.0253319
• Positron Lifetime in Lead Bromide Perovskite: delocalization versus capture at defects depending on composition and preparation
  
  • Nahdi H.
  • Helm R.
  • Iherenberger J.
  • Lemercier T.
  • Heshmati N.
  • Desgardin P.
  • Tondelier D.
  • Bourée J.E
  • Gros D’aillon E.
  • Zaccaro F.
  • Ceratti D.
  • Oswald F.
  • Bonnassieux Y.
  • Fisher T.
  • Mathur S.
  • Mitteneder J.
  • Liedke M.O.
  • Madaan K.
  • Roma G.
  • Pochet P.
  • L. Liszkay J.
  • Dickmann M.
  • Wagner A.
  • Barthe M.F.
  • Egger W.
  • Corbel C.
  , 2025.
• Enhancing hole mobility in p-type thin-film transistors: the impact of annealing in air on intrinsic and p+ µc-Si:H films deposited at 100 °C
  
  • Dolgoborodov Semen
  • Olivares Antonio
  • Cabarrocas Pere Roca I
  • Anutgan Mustafa
  • Anutgan Tamila
  Journal of Materials Science: Materials in Electronics, Springer Verlag, 2025, 36 (15), pp.876. Abstract P-type bottom gate (BG) microcrystalline silicon (µc-Si:H) thin-film transistors (TFTs) were fabricated utilizing intrinsic and p + µc-Si:H films grown at a low process temperature of 100 °C via plasma-enhanced chemical vapor deposition (PECVD) technique. The study explored the impact of 10-min annealing treatment within the temperature range of 200–350 °C on the hole mobility in both p + µc-Si:H films and BG TFTs. The as-grown p + µc-Si:H films exhibited notably high hole mobilities compared to the usual values, with further enhancement observed after annealing in air (2–3 cm 2 /(V s)). As for the field-effect mobility of p-type BG TFTs, it was within the usual range for the fresh devices. Similar to the mobility improvement in p + films, the p-type TFT mobility experienced a significant increase following annealing in air, compared to vacuum annealing. Further subjection of the TFT to annealing in air at elevated temperatures up to 350 °C resulted in a progressive enhancement in field-effect mobility up to ⁓0.13 cm 2 /(V s). Other important consequences are the decrease in the TFT threshold voltage and the improvement in its electrical stability. These findings emphasize the importance of applying a simple and short low-temperature annealing treatment in air for advancing the p-type BG µc-Si:H TFT performance, thereby rendering them viable for CMOS applications. The mechanism underlying this positive effect of the annealing in air was investigated by the attenuated-total-reflection (ATR) Fourier transform infrared (FTIR), Ultraviolet–Visible–near infrared (UV–VIS–NIR) spectroscopies, and computer simulations of the TFT transfer characteristics. (10.1007/s10854-025-14950-5)
  DOI : 10.1007/s10854-025-14950-5
• Safe Electrolytes for High-Energy Lithium-Sulfur Batteries
  
  • Li Shuang
  , 2025. Lithium-sulfur batteries (LSBs) are regarded as one of the most promising candidates for next-generation energy storage systems. Among all existing positive electrode materials, sulfur boasts one of the highest theoretical specific capacities, reaching 1675 mAh g-1 and it is an environmentally friendly natural resource. Furthermore, at the cell level, the coupling of metallic lithium and sulfur yields a theoretical specific energy of 2600 Wh kg-1, surpassing traditional lithium-ion batteries. Despite their potential, the development of LSBs faces intrinsic challenges, including the insulating nature of sulfur, end-product lithium sulfide issues, the "shuttle effect" caused by soluble intermediates of polysulfide, the lithium dendrite formation, as well as the safety concerns related to the flammability and possible leakage of traditional organic liquid electrolytes, which limits the commercialization of LSBs. In this thesis, polymer quasi solid-state electrolytes (PQSSEs) have gained attention for their potential to act as a physical barrier or chemical barrier against polysulfide migration, suppression of lithium dendrite growth, and their high flame resistance. Furthermore, PQSSEs stand out due to their increased safety and flexibility compared with other types of solid-state electrolytes. This thesis focuses on the fabrication of optimized VACNTs@S cathode configurations and synthesis of four types of potential polymer electrolytes via polymerization or cross linking reaction. Various synthesis strategies, including in-situ and ex-situ approaches, were explored to evaluate their impact on the performance of LSBs. Additionally, gel-state and membrane solid-state electrolytes were compared to assess their compatibility with well-designed nanostructured VACNTs@S cathode configuration.
• Rod-Shaped Nanographenes as Emitters in Fluorescent OLEDs
  
  • Lucas Fabien
  • Medina-Lopez Daniel
  • Banga-Kpako Cynthia
  • Huynh Thanh Trung
  • Lauret Jean-Sébastien
  • Campidelli Stéphane
  ACS Applied Nano Materials, American Chemical Society, 2025, 8 (16), pp.8473-8479. A significant challenge in the field of organic light-emitting diodes (OLEDs) technology is the development of stable, cost-effective, and sustainable emitters. Current emitters are frequently based on rare metals and heteroatom-based chromophores. Carbon-based nanomaterials, such as carbon dots (CDs) or nanographenes (NGs), offer a promising alternative due to their high photoluminescence quantum yields, the abundance of carbon materials, and the versatility of their syntheses. In this work, we fabricated green-light-emitting electroluminescent devices containing C60-tBu8 nanographene acting as the emitter. This nanographene contains 60 sp2 carbon atoms and tert-butyl solubilizing group on the periphery; it was synthesized via the bottom-up approach. The C60-tBu8 was fully characterized, and it was incorporated into the emissive layer of a benchmark OLED stack (ITO/PEDOT:PSS/NG-containing active layer/BCP/TmPyPB/LiF/Al). The OLED devices containing the C60-tBu8 exhibited current and power efficiencies (CE and PE) of 2.27 cd·A–1, 0.28 lm·W–1 and luminance of 164 cd·m–2. The performance remains modest in comparison to state-of-the-art OLEDs, but it outperforms previous attempts to utilize nanographenes as active materials for fluorescent OLEDs. Following the initial results, we also tested two other NGs (C78-tBu6 and C96-tBu8), which contain 78 and 96 sp2 carbon atoms as fluorescent emitters in OLEDs. The objective was to fine-tune the electroluminescence to yellow-orange and red light. (10.1021/acsanm.5c01332)
  DOI : 10.1021/acsanm.5c01332
• Investigation of the ageing behaviour of triple mesoscopic perovskite solar cells under outdoor working conditions
  
  • Var Maximilien
  • Oswald Frédéric
  • Bonnassieux Yvan
  • Migan-Dubois Anne
  • Jaffré Alexandre
  • Narbey Stéphanie
  • Parra J.
  , 2025. The photovoltaic industry’s dependence on critical raw materials such as silver raises sustainability concerns. This work explores rare-metal-free triple mesoscopic solar cells (m-TiO₂/m-ZrO₂/m-Carbon), easily fabricated by screen printing or doctor blading. The study focuses on the mesoporous carbon layer, acting as both hole-transporting and hole-collecting material, and on developing a conductive carbon ink with suitable rheology for thin film deposition. Applied to MAPbI₃ perovskite cells, these structures are evaluated under real outdoor conditions at the SIRTA site, demonstrating their potential for sustainable, low-cost photovoltaic technologies.
• Self-Consistent Field algorithms in Restricted Open-Shell Hartree-Fock
  
  • Benda Robert
  • Vidal Laurent
  • Giner Emmanuel
  • Cancès Eric
  , 2021. In this chapter, we propose a simple geometrical derivation of the restricted open-shell Hartree-Fock (ROHF) equations in the density matrix and molecular orbitals formalism. We then introduce a new, parameter-free, basic fixed-point method to solve these equations, that, in contrast with existing self consistent field (SCF) schemes, is not based on the introduction of a non-physical, parameter-dependent, composite Hamiltonian. We also extend the Optimal Damping Algorithm to the ROHF framework. We finally present numerical results on challenging systems (complexes with transition metals) demonstrating the performance of the new algorithms we propose.
• Contrôle du port de la ceinture de sécurité par imagerie polarimétrique
  
  • Eya Rjiba
  • Caurel Enrique Garcia
  • Rungasamy Koumara
  • Boffety Matthieu
  • Sortais Yvan R. P.
  , 2025.
• High power piezoelectric energy harvester for a temperature monitoring system
  
  • Kovacova Veronika
  • Alluri Nagamalleswara Rao
  • Bouton Olivier
  • Polesel Jérôme
  • Granzow Torsten
  • Frick Vincent
  • Wassouf Liana
  • Cojocaru Costel Sorin
  • Feugnet Gilles
  • Bondavalli Paolo
  • Defay Emmanuel
  APL Electronic Devices, AIP Publishing, 2025, 1 (1). In this study, we present a lead-free, piezoelectric energy harvester capable of generating power in the milliwatt range. The harvester consists of four layers of polyvinylidene difluoride piezoelectric polymer, bonded to a cantilever with a tip mass. The cantilever’s resonance frequency was measured at 13.4 Hz. The piezoelectric layers are connected in parallel, resulting in a total capacitance of 27 nF. At resonance, under open-circuit conditions, the harvester generates nearly 90 Vpp when subjected to an acceleration of 1 g. When impedance is matched, the maximum power output reaches 2.4 mW. In addition, we integrated the harvester with commercially available signal conditioning cards, enabling conversion from an AC signal to a steady 3.3 V DC signal useful for electronics to evaluate their efficiency in charging a capacitor. Finally, we demonstrated the harvester’s functionality in an autonomous system that measures and displays temperature on a digital screen. The system operated autonomously for 6.5 h. (10.1063/5.0253362)
  DOI : 10.1063/5.0253362
• Theoretical study of the non-covalent functionalization of carbon nanotubes for NO and CO detection
  
  • Bensifia Mohamed
  • Bouanis Fatima
  • Léonard Céline
  Computational Condensed Matter, Elsevier, 2025, 42, pp.e00998. Sensing CO and NO gases at room temperature (RT) is of great significance for various industrial and environmental sectors including, pollution monitoring, commercial safety, and medical services, among others. Nanomaterials such as single-walled carbon nanotubes (SWNTs) have emerged as promising candidates for RT gas-sensing applications due to their unique intrinsic properties. Herein, we reported a theoretical study of semiconductor-SWNTs (8,0) as sensitive layer for CO and NO detection. To improve their sensing performance, semiconductor-SWNTs (8,0) were non-covalently functionalized with a series of metalloporphyrins and metallophthalocyanines molecules such as cobalt(II)-phthalocyanine (Pht-Co), cobalt(II)-porphyrin (Por-Co) and iron(II)-porphyrin (Por-Fe). A charge transfer between the functionalizing molecules and SWNTs induces n-type doping of SWNTs. The functionalized SWNTs exhibited superior sensitivity and attachment capacity toward NO and CO compared to pristine SWNTs. By analyzing the interaction between gases and different functionalized SWNTs molecules, the results showed that NO acts as an electron acceptor with all systems. However, CO reacts as an electron donor with Por-Co and Pht-Co functionalized SWNTs and as an electron acceptor with SWNT (8,0) + Por-Fe. From the set of tested molecules, Por-Co is the best candidate for selective detection of both CO and NO with different signals depending on the gas nature. (10.1016/j.cocom.2024.e00998)
  DOI : 10.1016/j.cocom.2024.e00998
• Characterization of photophysical and electrochemical properties of a PNDT-T-DPP dye-based polymer with highly planar features and development of organic electronic applications
  
  • Chen Jinyang
  • Zhao Yue
  • Zeng Wenxiang
  • Ni Pingping
  • Wang Yujie
  • Chen Shuchang
  • Yuan Xianhe
  • Feng Zhuowen
  • Tang Suhong
  • Wang Sichun
  • Ren Shiwei
  • Yassar Abderrahim
  Dyes and Pigments, Elsevier, 2025, 234, pp.112536. Common organic small molecule dyes exhibit chemical modifiability and are easy to polymerize, making them potential monomers in organic electronics. The multifunctionality of organic synthetic chemistry allows for material adaptability. Here, we report the synthesis route and purification methods for dye polymer based on thiophene-diketopyrrolopyrrole. Their orderly conjugated structure and high coplanarity contribute to a high crystallinity, which is favorable for charge carrier transport. By adjusting the device structure and thin film preparation conditions, the hole transport properties of the materials were further optimized, achieving a maximum mobility of up to 0.35 cm 2 V -1 s -1 . The excellent charge carrier performance reveals the potential of such materials for applications in organic electronics. (10.1016/j.dyepig.2024.112536)
  DOI : 10.1016/j.dyepig.2024.112536
• Spin-crossover and high magnetic anisotropy in organometallic structures: W3C6O6 and Re3C6O6
  
  • Denawi Adam Hassan
  • Vach Holger
  • Das Kausik
  • Oison Vincent
  • Hayn Roland
  Materials Today Communications, Elsevier, 2025, 44, pp.112165. Organometallic monolayers of the form TM3C6O6 where TM is any possible transition metal are a very promising material class. Some members of this family with 3d transition metals had been synthesized on noble metal surfaces and we extend here the study to two metals, Tungsten (W) and Rhenium (Re), of the 5d series by the use of ab-initio calculations. One of the key findings is the discovery of spin-crossover behavior in both monolayers. Especially interesting is the spin-crossover behavior of Re3C6O6 which exhibits a transition from intermediate- spin (semiconducting) to high-spin (metallic) states, leading to a significant change in the bandgap, affecting its electrical behavior. In W3C6O6, a small gap in the electronic band structure has been observed. Furthermore, a remarkable high magnetic anisotropy energy has been found in these organometallics with 5d transition metals. Besides the ab-initio energy differences, also the parameters of a Heisenberg model with local anisotropy energies have been determined. The presence of high magnetic anisotropy energies in these organometallics makes them beneficial for potential technological applications, particularly in magnetic storage, spintronics, and other magnetic-based technologies. The high magnetic anisotropy also holds promise for quantum computing, where stable and robust magnetic qubits are essential for information storage and manipulation. Additionally, these materials with high magnetic anisotropy energies are of great interest in fundamental research as they can provide valuable insights into the underlying magnetic interactions and electronic structure of the compounds. In summary, our study highlights the fascinating properties of TM3C6O6 organometallics, with implications for future technologies, quantum computing, and fundamental research in the field of magnetic materials. Furthermore, the discovery of spin-crossover behavior of these materials opens up exciting possibilities for their use in future technologies and epitaxy on different substrates. (10.1016/j.mtcomm.2025.112165)
  DOI : 10.1016/j.mtcomm.2025.112165
• Homoepitaxial growth of device-grade GaAs using low-pressure remote plasma CVD
  
  • Watrin Lise
  • Silva François
  • Largeau Ludovic
  • Findling Nathaniel
  • Al Katrib Mirella
  • Bouttemy Muriel
  • Dembélé Kassiogé
  • Vaissière Nicolas
  • Jadaud Cyril
  • Bulkin Pavel
  • Vanel Jean-Charles
  • Johnson Erik
  • Ouaras Karim
  • Cabarrocas Pere Roca I
  Materials Science in Semiconductor Processing, Elsevier, 2025, 186, pp.109069. (10.1016/j.mssp.2024.109069)
  DOI : 10.1016/j.mssp.2024.109069
• Homoepitaxial growth of device-grade GaAs using low-pressure remote plasma CVD
  
  • Watrin Lise
  • Silva François
  • Largeau Ludovic
  • Findling Nathaniel
  • Al Katrib Mirella
  • Bouttemy Muriel
  • Dembélé Kassiogé
  • Vaissière Nicolas
  • Jadaud Cyril
  • Bulkin Pavel
  • Vanel Jean-Charles
  • Johnson Erik
  • Ouaras Karim
  • Cabarrocas Pere Roca I
  Materials Science in Semiconductor Processing, Elsevier, 2025, 186, pp.109069. (10.1016/j.mssp.2024.109069)
  DOI : 10.1016/j.mssp.2024.109069
• Chemical transport-based growth of Si and SiGe nanowires
  
  • Yang Ke
  • Zhu Xianjun
  • Gong Ruiling
  • Florea Ileana
  • Roca i Cabarrocas Pere
  • Chen Wanghua
  Journal of Applied Physics, American Institute of Physics, 2025, 137 (4). This study investigates the chemical transport-based growth of Si and Ge nanowires (NWs) using plasma-enhanced chemical vapor deposition. We found that Si NW growth requires a high etching temperature of 400 °C, related to a stronger Si–H bond energy compared to the Ge–H bond energy, allowing Ge NWs to form at 250 °C. The growth process is influenced by various parameters, including etching temperature, radio frequency power, GeH4/SiH4 precursor gas ratios, doping, and inter-electrode distance. Optimal Si NW growth is achieved at a substrate temperature of 250 °C during pre-coating and 400 °C during etching, with an RF power of 100 W. Conversely, Ge NWs can be fabricated at 250 °C, although they tend to be smaller and less dense. The study also highlights the role of the doping of the amorphous film precursors, with n-type doping enhancing growth and crystallization, while p-type doping negatively affects NW formation. Key findings include the significance of maintaining optimal etching time and its effect on NW morphology and uniformity. Overall, the results provide a novel method for efficiently growing Si and Ge NWs, emphasizing the importance of carefully controlling growth conditions. (10.1063/5.0249864)
  DOI : 10.1063/5.0249864
• Chemical transport-based growth of Si and SiGe nanowires
  
  • Yang Ke
  • Zhu Xianjun
  • Gong Ruiling
  • Florea Ileana
  • Roca i Cabarrocas Pere
  • Chen Wanghua
  Journal of Applied Physics, American Institute of Physics, 2025, 137 (4). This study investigates the chemical transport-based growth of Si and Ge nanowires (NWs) using plasma-enhanced chemical vapor deposition. We found that Si NW growth requires a high etching temperature of 400 °C, related to a stronger Si–H bond energy compared to the Ge–H bond energy, allowing Ge NWs to form at 250 °C. The growth process is influenced by various parameters, including etching temperature, radio frequency power, GeH4/SiH4 precursor gas ratios, doping, and inter-electrode distance. Optimal Si NW growth is achieved at a substrate temperature of 250 °C during pre-coating and 400 °C during etching, with an RF power of 100 W. Conversely, Ge NWs can be fabricated at 250 °C, although they tend to be smaller and less dense. The study also highlights the role of the doping of the amorphous film precursors, with n-type doping enhancing growth and crystallization, while p-type doping negatively affects NW formation. Key findings include the significance of maintaining optimal etching time and its effect on NW morphology and uniformity. Overall, the results provide a novel method for efficiently growing Si and Ge NWs, emphasizing the importance of carefully controlling growth conditions. (10.1063/5.0249864)
  DOI : 10.1063/5.0249864
• Development of a rabbit model of uterine rupture after caesarean section, Histological, biomechanical and polarimetric analysis of the uterine tissue
  
  • Debras Elodie
  • Maudot Constance
  • Allain Jean-Marc
  • Pierangelo Angelo
  • Courilleau Aymeric
  • Rivière Julie
  • Dahirel Michèle
  • Richard Christophe
  • Gelin Valérie
  • Morin Gwendoline
  • Capmas Perrine
  • Chavatte-Palmer Pascale
  Reproduction & Fertility, Bioscientifica Ltd, 2025, 6 (4), pp.e-250018. Uterine rupture is a major complication of caesarean section (CS) associated with a high foetal and maternal morbidity. The objective is to develop an in-vivo model of uterus healing and rupture after CS in order to analyse histological phenomena controlling scarring tissue development and potential cause of defects. Eighteen pregnant primiparous female rabbits were bred naturally. At caesarean, after 28 days of gestation, foetuses were either extracted through a longitudinal incision in one of the uterine horns (“CS horn”) or via a short incision at the tip of the contralateral horn (“control horn”). The uterine horns were sutured by single layer, all by the same surgeon. They were mated again 14 days later and euthanized at G28. Genital tracts were collected for histological, biomechanical and polarimetric analyses. Macroscopically, 2/18 presented a dehiscence and 1/18 a spontaneous rupture. The mean thickness of the scarred area was significantly lower 0.9 mm [0.7-1.4] that the non-scarring area on CS horns 2.2 [1.6-2.3] or control horns 2 [1.5-2.3] (p&lt;0.0001). The scar zone was statistically more fibrous (p&lt;0.0001), containing fewer vessels (p=0.03) and oestrogen (p&lt;0.001) and progesterone receptors (p&lt;0.0001). After balloon inflation, ruptured occurred in the scar zone in 8 out of 17 cases (47%). Polarimetry revealed that the scar zone was statistically inhomogeneous (73%). Multifactorial analysis allowed to identify groups with poor uterine healing and less resistant to rupture (balloon inflation) mostly in case of thin myometrium in the scar and a group with strong resistant to rupture and correct healing characteristics. Lay summary Caesarean section rates are rising across the world. When a caesarean section is carried out, it can lead to scarring on the uterus that can affect its resistance to pressure. During the next pregnancy, the uterus can tear, increasing risks to the mother and baby. We carried out caesarean sections in a rabbit, allowing us to analyse the scar on the uterus, the healing and tissue resistance. The scarred part of the uterus was statistically thinner, more fibrous and contained fewer vessels and hormone receptors than the area without scarring. Under similar conditions, poor healing was observed in some animals, reducing resistance in following pregnancies. These results suggest that individual and genetic factor have an effect on healing after a caesarean section. This study may enable us to improve our knowledge and management care for patients who have a caesarean section in order to reduce complications. (10.1530/raf-25-0018)
  DOI : 10.1530/raf-25-0018
• Seat belt detection using polarimetric imaging
  
  • Rjiba Eya
  • Garcia-Caurel Enrique
  • Ossikovski Razvigor
  • Rungasamy Koumara
  • Boffety Matthieu
  • Sortais Yvan R. P.
  Applied optics, Optical Society of America, 2025. (10.1364/AO.573295)
  DOI : 10.1364/AO.573295
• Vacancy Functionalized MoS₂ Nanolaminated Membranes for Efficient Sieving in Forward Osmosis
  
  • Ying Ting
  • Onofrio Nicolas
  • Mei Liang
  • Peng Huarong
  • Zhang Zhen
  • Gu Meng
  • Ma Chen
  • Chen Ye
  • Zhou Jiang
  • Leung Kenneth M Y
  • Cheng Chong
  • Li Shuang
  • Liu Bilu
  • Tang Chuyang Y
  • Voiry Damien
  • Zeng Zhiyuan
  Advanced Materials, Wiley-VCH Verlag, 2025, 37 (41), pp.e04781. 2D transition‐metal dichalcogenides (TMDs) based nanolaminates are promising candidates for water purification. However, fabricating nanochannels with tunable capillary widths remain a challenge. This study proposed a sulfur vacancy functionalization strategy for fabricating high performance nanolaminate membranes by grafting three kinds of thiol (S‐H) containing molecules (Cysteine, 3‐Mercapto‐1,2‐propanediol, 1‐Propanethiol) on MoS₂ nanosheets, in which propanethiol functionalized MoS₂ membrane exhibited best salt rejection (99.3%) and water/salt selectivity (800 bar −1 ) in forward osmosis (draw solution: sucrose solution). It is found the capillary width increased from 0.2 Å in pristine MoS 2 to ≈5 Å in propanethiol functionalized MoS₂ membranes. Numerical simulations suggest that nanofluidic properties of the functionalized membranes are governed by the fundamental interaction between water and the corresponding S‐H functional group, and the interlayer distance. Importantly, since the S‐H containing molecules can repair MoS₂ nanosheets by fitting into the sulfur vacancies, the stability of the membranes is also improved with minimal swelling, which is promising for their practical applications. (10.1002/adma.202504781)
  DOI : 10.1002/adma.202504781
• Synthesis of Sn-catalyzed Ge nanowires and Ge/Si heterostructures via a gradient method
  
  • Zhu Xianjun
  • Shen Ya
  • Florea Ileana
  • Roca i Cabarrocas Pere
  • Chen Wanghua
  Materials Letters, Elsevier, 2025, 379, pp.137674. (10.1016/j.matlet.2024.137674)
  DOI : 10.1016/j.matlet.2024.137674
• Pyrimidine‐Based Four‐Coordinate O^N^O Boron Complexes: Synthesis, Photophysical and Theoretical Studies, and TADF‐Based OLED Devices
  
  • Diguet Clément
  • Navarro Amparo
  • Fernández-Liencres M. Paz
  • B. Jiménez-Pulido Sonia
  • A. Illán-Cabeza Nuria
  • Almutairi Abdullah
  • Tondelier Denis
  • Gauthier Sébastien
  • Robin-Le Guen Françoise
  • Rodríguez-López Julián
  • Massue Julien
  • Achelle Sylvain
  Chemistry - A European Journal, Wiley-VCH Verlag, 2025. This article describes the synthesis, along with the full photophysical and computational characterization, of a series of push‐pull boron complexes comprising a sterically hindered donor connected to a pyrimidine‐based O^N^O boron chelate. The dimethylacridan‐functionalized fluorophore appears to be the most emissive in the series, both in toluene solution and in the solid state (as a powder), displaying thermally activated delayed fluorescence (TADF) emission in degassed media due to a small singlet‐triplet energy gap. This result is in line with a previously reported pyridine analogue, which also exhibits delayed emission. Incorporation of this TADF compound into an organic light‐emitting diode led to the observation of intense electroluminescence, with EQEmax values reaching 9.7% at a 5 wt% doping concentration. (10.1002/chem.202501089)
  DOI : 10.1002/chem.202501089
• Investigation of substrate and hydrogen pretreatment time to modulate SWCNT diameter and growth yield
  
  • Taoum Haifa
  • Ezzedine Mariam
  • Cojocaru Costel-Sorin
  Applied Surface Science, Elsevier, 2025, 691, pp.162664. Synthesizing high-quality single-walled carbon nanotubes (SWCNT) requires innovative approaches that surpass traditional catalysts supported on amorphous alumina or silica. This study investigates SWCNT growth on various substrates, including SiO₂/Si, quartz, C-sapphire, and R-sapphire, with and without a 5 nm amorphous alumina buffer layer, using different pretreatment times via hot-filament catalytic chemical vapor deposition (HF-CCVD). A 30-seconds atomic hydrogen pretreatment effectively promotes SWCNT growth on all plain substrates. The addition of the thin alumina buffer layer further enhances yield, resulting in a dense network of SWCNT. However, extending the pretreatment to 120 s leads to catalyst particle coarsening via Ostwald ripening, significantly reducing SWCNT yield and favoring multi-walled carbon nanotubes (MWCNT) formation, regardless of the presence of a buffer layer. Our results demonstrate that Fe catalyst activity and the resulting CNT structure is tightly linked to substrate characteristics, including crystallinity, porosity, and surface roughness. Importantly, high-yield SWCNT growth is achievable directly on plain substrates without the need for an alumina buffer layer. This work highlights the critical role of substrate-catalyst interactions in CNT synthesis and highlights the potential for fine-tuning SWCNT growth under short atomic hydrogen pretreatment conditions. (10.1016/j.apsusc.2025.162664)
  DOI : 10.1016/j.apsusc.2025.162664
• Electric fields, forces, and modification of the tunnel barrier during field electron emission and field evaporation from single-wall carbon nanotubes
  
  • Pimonov Vladimir
  • Panciera Federico
  • Rouille Goulven
  • Weng Catherine
  • Perisanu Sorin
  • Cojocaru Costel Sorin
  • Taoum Haifa
  • Wei Chen
  • Barranco Carceles Salvador
  • Verdugo-Gutiérrez Victor
  • Aguili Ilias
  • Sivignon Jean Francois
  • Blanchard Nicholas
  • Legagneux Pierre
  • Purcell Stephen Thomas
  • Ayari Anthony
  • Vincent Pascal
  Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics, AVS through the American Institute of Physics, 2025, 43 (4), pp.043202. In this paper, we theoretically and experimentally investigate the specificities of single-walled carbon nanotubes (SWNTs) for field electron emission (FE) and field ion evaporation (FI). For FE, the small radii of curvature of these nanotubes lead to a significant widening of the tunnel barrier, and thus, for a given emission current, the fields at the surface of the SWNTs are significantly higher than commonly observed in standard large radius FE. For currents in the μA range, for example, fields ranging from 7–8 V/nm for large nanotubes to 17–18 V/nm for the thinnest are required. These strong fields, in turn, have repercussions on FI and electrostatic forces. The electric fields and longitudinal electrostatic forces during FE and FI as a function of nanotube radius are presented. The evolution of the nanotube during field evaporation was also studied in an environmental transmission electron microscope as a function of field strength and polarity. A strong dissymmetry between positive and negative polarity is observed. For negative polarity, the nanotubes can gradually shorten as the voltage is increased, whereas in positive polarity, they are almost systematically torn off before apex evaporation occurs. A model to explain this dissymmetry for our samples is presented. These results can be used to optimize nanotube cathode geometries. (10.1116/6.0004707)
  DOI : 10.1116/6.0004707