Roberto Lazzaroni

Université de Mons · Department of Chemistry

High-resolution transmission electron microscopy (TEM) of organic crystals, such as Lead Phthalocyanine (PbPc), is very challenging since these materials are prone to electron beam damage leading to the breakdown of the crystal structure during investigation. Quantification of the damage is imperative to enable high-resolution imaging of PbPc cryst...

Two-dimensional (2D) chirality has been actively studied in view of numerous applications of chiral surfaces such as in chiral resolutions and enantioselective catalysis. Here, we report on the expression and amplification of chirality in hybrid 2D metallosupramolecular networks formed by a nucleobase derivative. Self-assembly of a guanine derivati...

Graphitic carbon nitride (gCN) is an important heterogeneous metal-free catalytic material. Thermally induced post-synthetic modifications, such as amorphization and/or reduction, were recently used to enhance the photocatalytic response of these materials for certain classes of organic transformations, with structural defects possibly playing an i...

Spiro compounds are widely used as host matrices in organic light‐emitting diodes (OLEDs). Here, inspired by the recent developments in thermally activated delayed fluorescence (TADF) materials, the potential as a light emitter of two spiro‐configured organic semi‐conductors is investigated, constructed by the association of quinolinophenothiazine...

Nanoscale Electrical Investigation of Transparent Conductive Electrodes In article number 2200019, Sy Hieu Pham, Philippe Leclère, and co-workers analyze at the nanoscale the current percolation mechanisms through a silver nanowire mesh. This network is successfully used for transparent and flexible electrodes in organic and hybrid electronic devic...

Presently, metallic nanowires (NWs) are the most promising materials to fabricate flexible transparent electrodes as an alternative to indium tin oxide. Here, the high performance of transparent conductive electrodes (TCEs) based on silver nanowires (AgNWs) percolation networks is reported. With optimized experimental conditions for the deposition,...

Nanoscopic lateral confinement created on a graphite surface enabled the study of embryonic stages of molecular self-assembly on solid surfaces using scanning tunneling microscopy performed at the solution/solid interface.

Aiming to develop efficient blue-emitting thermally activated delayed fluorescence (TADF) compounds, we have designed and synthesized derivatives of the well-known sky-blue emitter 2CzPN that contain electron-accepting phosphine chalcogenide groups to...

Aiming to develop efficient blue-emitting thermally activated delayed fluorescence (TADF) compounds, we have designed and synthesized derivatives of the well-known sky-blue emitter 2CzPN that contain electron-accepting phosphine chalcogenide groups to stabilize the HOMO level relative to the pristine compound, thus increasing the HOMO-LUMO gap and...

Aiming to develop efficient blue-emitting thermally activated delayed fluorescence (TADF) compounds, we have designed and synthesized derivatives of the well-known sky-blue emitter 2CzPN that contain electron-accepting phosphine chalcogenide groups to stabilize the HOMO level relative to the pristine compound, thus increasing the HOMO-LUMO gap and...

Precise characterization of the hydrogen bond network present in discrete self-assemblies of benzene-1,3,5-tricarboxamide monomers derived from amino-esters (ester BTAs) is crucial for the construction of elaborated functional co-assemblies. For all...

We utilize dynamic light scattering (DLS) and passive microrheology to examine the phase behavior of a supramolecular polymer at very high pressures. The monomer, 2,4-bis(2-ethylhexylureido)toluene (EHUT), self-assembles into supramolecular polymeric structures in the nonpolar solvent cyclohexane by means of hydrogen bonding. By varying the concent...

The presence of an opportune impurity can change the on-surface assembly behavior via preferential adsorption and nucleation.

The synthesis of a novel polyhedral oligomeric silsesquioxane functionalized with eight rigid and directional terpyridine-based arms (Ter-POSS) was successfully achieved via Sonogashira reaction. The POSS based ligand was extensively characterized...

Hydrogen bonding is an indispensable tenet in the fabrication of surface-confined physisorbed supramolecular networks. On-surface supramolecular chemistry is dominated by aromatic carboxylic acids, which allow implementation of highly directional and robust design elements in the form of hydrogen bonds. In this article, we investigate the influence...

Understanding the surface properties of hybrid perovskite materials is a key aspect to improve not only the interface properties in photovoltaic cells but also the stability against moisture degradation. In this work, we study the local electronic properties of two series of CH3NH3PbI3 perovskite films by Atomic Force Microscopy-based methods. We c...

The synthesis of 5-hydroxymethylfurfural (5-HMF) and 2-furfural (2-F) by hexoses and pentoses dehydration is considered as a promising path to produce materials from renewable resources. Low-transition-temperature mixtures (LTTMs) enable selective (>80%) dehydration of ketoses to furanic derivatives at moderate temperature (<100 • C). However, aldo...

Phosphonium‐based polythiophene conjugated polyelectrolytes (CPEs) with three different counterions (dodecylsulfate (DS), octylsulfate (OS) and perfluorooctylsulfonate (PFOS)) are synthesized to determine how the nature of the counterion affects the thermal properties, the self‐assembly in thin films and the performance as cathode interfacial layer...

1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) polymerizes rac-lactide (rac-LA) to form highly isotactic polylactide (PLA) with a Pm = 0.88, while meso-LA yields heterotactic PLA (Pm ~ 0.8) at −75 °C. The stereocontrol of the cryogenic-based ring-opening polymerization comes from a perfect imbrication of both chiral LA and the propagating chiral end-gro...

1,1’-disubstituted-2,3,4,5-tetraphenylsiloles incorporating triptycene moieties Tp-DMTPS and Tp-MPTPS were prepared and characterized. Like other 2,3,4,5-tetraphenylsiloles, both compounds exhibit aggregation-induced emission (AIE) behavior. Unexpectedly, the solid state PL emission of Tp-DMTPS show dependence according to the degree of crystallini...

Chlorophyll a derivatives were integrated in “all solid-state” dye sensitized solar cells (DSSCs) with a mesoporous TiO2 electrode and 2′,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene as the hole-transport material. Despite modest power conversion efficiencies (PCEs) between 0.26% and 0.55% achieved for these chlorin dyes, a s...

The synthesis and characterization of two new anthradithiophene (ADT) derivatives bearing electron donating (triphenylamine) or accepting (5-formylthiophen-2-yl unit) moieties have been performed to assess their potential as materials for organic photovoltaics. Optical spectroscopy was used to evaluate the effect of electron rich/poor substituents...

We have used atomistic simulations to study the network topology and the thermomechanical properties of the methyl-4,4-bis-[6-(3-phenyl-3,4-dihydro-2H-1,3-benzoxazine)]pentanoate based system (MDP-a), in comparison to commercially available bisphenol-A based benzoxazine (Ba-a). In the first part of the work, we focus on the role of the transesterif...

Increasing the crystallinity of thin films in concert with the planarization of the conjugated backbones has long been considered as the key for success in the design of polymer materials with optimized charge transport properties. Recently, this general belief had to be revisited with the emergence of a new class of disordered or even seemingly am...

Patterned and layered hydrophilic/phobic coatings were deposited on multiple surfaces using non-fluorinated precursors (AA - acrylic acid and PMA - propargyl methacrylate) with an atmospheric pressure dielectric barrier discharge operating in open air. Water contact angles of the resulting films could be tuned from < 5° (superhydrophilic) to > 135°...

A poly(3-hexylthiophene)-block-perfluoropolyether-block-poly(3-hexylthiophene) (P3HT-b-PFPE-b-P3HT) triblock copolymer was synthesized by copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) in 95% yield. The copolymer was unequivocally characterized by size exclusion chromatography reaching 27 000 g mol(-1) and nuclear magnetic resonance (NMR)....

In order to rationalize how the gelation ability of a low molecular weight gelator is influenced by its molecular structure, we performed extensive solubility tests of a group of thiazole based gelators and made use of Hansen solubility parameters formalism. We observe that the increase of a linear alkyl chain in these gelators promotes an increase...

Critical load measurements point to an improvement in the hardness of a soda–lime glass upon nitrogen implantation. In order to determine whether this improvement originates from electronic doping or surface composition changes induced by ion implantation, a theoretical approach using quantum‐chemical and force‐field methods combined with X‐ray pho...

End-functionalized poly(3-hexylthiophene) (P3HT) and poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA) were synthesized using controlled polymerization techniques and linked together to lead to a diblock copolymer structure via click cycloaddition. These diblock copolymers were further blended with carbon nanotubes (CNTs) to be used...

Sepiolite (Sep)⁻styrene butadiene rubber (SBR) nanocomposites were prepared by using nano-sized sepiolite (NS-SepS9) fibers, obtained by applying a controlled surface acid treatment, also in the presence of a silane coupling agent (NS-SilSepS9). Sep/SBR nanocomposites were used as a model to study the influence of the modified sepiolite filler on t...

Graphene-based two-dimensional (2D) materials are promising candidates for a number of different energy applications. A particularly interesting one is in next generation supercapacitors, where graphene is being explored as an electrode material in combination with room temperature ionic liquids (ILs) as electrolytes. Because the amount of energy t...

We model coupled ion transport in representative electrolyte solutions for Li−S batteries by applying molecular dynamic (MD) simulations on systems of increasing complexity, namely going from solutions of the Li2S4 salt in pure tetraethylene glycol dimethyl ether (TEGDME) and 1,3‐dioxolane (DOL) solvents, to Li2S4 in solvent mixtures, and finally i...

We report the preparation and characterisation of a novel three‐dimensional organic material consisting of porphyrin arrays on carbon nanotubes embedded in an organogel. Firstly, the porphyrin array was prepared through metal–ligand coordination of a ditopic ligand (1,2‐bis(4‐pyridyl)ethane) and two bis‐Zn(II) porphyrins, linked through pyrene core...

This work aims at presenting an innovative method for tailoring the morphology of functionalized plasma polymer films (PPF). The approach is based on the formation of a plasma polymer bilayer system in which the two layers differ by their chemical composition and cross-linking degree. As a case study, propanethiol-based plasma polymer films have be...

Para-quinone-based electrode materials are largely studied as redox-active components of organic cathodes for lithium-ion batteries. Although they present high capacities, yet they suffer from a rather low reduction potential (2–3 V vs Li+/Li) that limits the practical voltage and thus, the specific energy of the device. In this paper, we demonstra...

The nanoscale morphology of photoactive hybrid heterojunctions plays a key role in the performances of hybrid solar cells. In this work, the heterojunctions consist of a nanocolumnar TiO2 surface covalently grafted with a monolayer of poly(3-hexylthiophene) (P3HT) functionalized with carboxylic groups (–COOH). Through a joint analysis of the photov...

Supporting Information. Figure S1 shows a FM-AFM height image obtained in UHV astride the step from a nanostructured TiO2/P3HT-COOH HHJ to the ITO electrode lying below. The applied DC sample bias was varied during the measurement, without illumination. This result aims at demonstrating the absence of floating potential across the layer composing t...

Fillers are widely used to improve the thermomechanical response of polymer matrices, yet often in an unpredictable manner because the relationships between the mechanical properties of the composite material and the primary (chemical) structure of its molecular components have remained elusive so far. Here, we report on a combined theoretical and...

Well‐defined pyrene‐based poly(2,2,6,6‐tetramethylpiperidinyloxy‐4‐yl methacrylate) (PTMA) (co)polymers have been synthesized and combined with multi‐wall carbon nanotubes (CNTs) as electrode material for organic radical batteries. The influence of the number of pyrene pendent groups on the electrochemical response of the nanocomposite materials ha...

To succeed in commercial applications, donor materials for organic solar cells should combine high stability and simple synthesis with high performance in devices. Here, we present a new small π-conjugated molecule, TPA-T-DCV-Ph, which meets those requirements. Simple and efficient three-step synthesis produces a push-pull molecule with triphenylam...

The interaction between 2,2′-bithiophene-5-carboxylic acid (PT2) sublimed under ultra-high vacuum conditions and anatase (101) and rutile (110) TiO2 single crystal surfaces is investigated by studying the electronic spectral density near the Fermi level with synchrotron-based spectroscopy. The experimental results are compared to density functional...

Halogen-halogen interactions are a particularly interesting class of halogen bonds that are known to be essential design elements in crystal engineering. In solution, it is likely that halogen-halogen interactions also play a role, but the weakness of this interaction makes it difficult to characterize or even simply detect. We have designed a supr...

The performance of organic nanostructures is closely related to the organization of the functional molecules. Frequently, molecular chirality plays a central role in the way molecules assemble at the supramolecular level. Herein we report the hierarchical self-assembly of benzo-fused tetrathia[7]helicenes on solid surfaces, from a single surface-bo...

We report (Time-Dependent) Density Functional Theory calculations characterizing the changes in the electronic and optical properties of oligothiophene dyes when grafted on a titania surface via a carboxylic acid or catechol moiety as anchoring group, in relation to their use in dye-sensitized solar cells. The broadening of the LUMO level of the co...

Water-soluble binders can enable greener and cost effective Li-ion battery manufacturing by eliminating the standard fluorine-based formulations and associated organic solvents. The issue with water-based dispersions, however, remains the difficulty to stabilize them, requiring additional processing complexity. Herein, we show that mechanochemical...

We present a comparative molecular modeling study of the thermomechanical properties of crosslinked benzoxazine resins. A crosslinking algorithm was developed in order to simulate the thermal curing of the thermoset resins and monitor the evolution of their network topology. The resin properties (gelation point, crosslink density, volumetric expans...

Chiral induction in self-assembled monolayers has garnered considerable attention in the recent past, not only due to its importance in chiral resolution and enantioselective heterogeneous catalysis but also because of its relevance to the origin of homochirality in life. Here, we demonstrate the emergence of homochirality in a supramolecular low-d...

This chapter discusses the applicability of different AFM-based techniques with force sensitivity of a few pN for mapping the nanostructure and quantifying the nanoscale mechanical properties of the surface of complex polymer coatings based on silicone oligomers in order to use them as bioadhesives. The AFM modes used are Peak Force Tapping and Con...

The association of kinetic studies, DFT calculations and 1H-7Li NMR analyses allowed to control the cyclo-ATRP of PEG9DMA and produce polymethacrylate pseudo crown-ethers of various molar masses. Their potential to act as solid state polyelectrolyte in Li-ion batteries has been highligthed and may come from the supramolecular organization of the cy...

In this work, glancing angle deposition and magnetron sputtering are combined to synthesize nanostructured Ti films. Different type of microstructures (tilted columns, straight pillars, zigzags) are obtained as a function of the experimental conditions. As a support, kinetic Monte Carlo simulations are performed to understand the observed trends us...

Abstract All solid-state dye-sensitized solar cells (ss-DSSCs) based on the reference D102 organic dye and using poly(3-hexylthiophene) (P3HT) as hole transporting material were fabricated and compared to the most used 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD). Power conversion efficiency of 4.78% was reac...

A density functional theory (DFT) study has been carried out on transition metal phosphates with olivine structure and formula LiMPO 4 (M = Fe, Mn, Co, Ni) to assess their potential as cathode materials in rechargeable Li-ion batteries based on their chemical and structural stability and high theoretical capacity. The investigation focuses on LiMnP...

This paper describes the synthesis and characterization of a new hybrid material based on poly(2,2,6,6-tetramethylpiperidin-1-oxyl-4-yl methacrylate) (PTMA) for lithium battery applications. Our strategy relies on the anchoring of nitroxide-embedding polymer chains onto multi-walled carbon nanotubes (MWCNTs). The resulting hybrid material (MWCNT-g-...

In the rapidly developing field of organic photovoltaics, the material design and device engineering are key factors that eventually determine the device efficiency. Design of the active layer material and intermolecular interactions largely determine the efficiency of organic solar cells. In this study, the authors discuss ultrafast photophysics o...

TiO2 nanotube arrays (TNA) elaborated on transparent and conducting substrates are promising materials for photoanodes in dye-sensitized solar cells as the reduced dimensionality enhances their transport properties. TNA were obtained by anodization of Ti films deposited by magnetron sputtering on transparent conducting oxide-coated glass. This stud...

Previously, we reported that the photo-oxidation of P3HT:PCBM was shown to induce an increase of the electric resistance at the active layer in the solar cells, resulting in a drop in the device performances. Meanwhile, fragments resulting from the partial molecular scission of P3HT chains were also detected by analyzing the produced materials usin...

Conjugated polymers and small molecules based on alternating electron donating (D) and electron accepting (A) building blocks have led to state-of-the-art organic solar cell materials governing efficiencies beyond 10%. Unfortunately, the connection of D and A building blocks via cross-coupling reactions does not always proceed as planned, which can...

We report the synthesis of all-conjugated branched poly(thiophenes) with a control over the degree of nonlinearity via two different routes. In the first approach a branched monomer is polymerized using three different catalysts which differentiate in the degree of association to the π-system of the polymer backbone. In the second approach a copoly...

Templated cooperative binding induced assembly of chromophores is achieved via interactions between Zn-complexes and the DNA phosphodiester backbone. The chromophores are organized in left-handed (M)-helices via double-zipper assembly with the DNA templates.

A heterochiral 1,3,5-benzene tricarboxamide (BTA) monomer, derived from valine dodecyl ester, forms long rods in cyclohexane whilst its homochiral analogue assembles into dimers only at the same concentration. This highly original assembly behaviour is related to the destabilization of the dimeric structure containing the two heterochiral monomers...

As the benzene 1,3,5-tricarboxamide (BTA) moiety is commonly used as the central assembling unit for the construction of functionalized supramolecular architectures, strategies to tailor the nature and stability of BTA assemblies are needed. The assembly properties of a library of structurally simple BTAs derived from amino dodecyl esters (ester BT...

WC/C:H thin films have been synthesized by a hybrid Plasma Enhanced Chemical Vapor Deposition/Physical Vapor Deposition method consisting in the reactive sputtering of a tungsten target in Ar-C2H2 atmospheres. The influence of the gas mixture on the physico-chemical properties of WC/C:H layers including their chemical composition, morphology, tribo...

PDMS-b-PAA block copolymers were synthesized in a two-step procedure. The first step involves atom transfer radical polymerization (ATRP) of the protected ethoxyethyl acrylate (EEA) monomer initiated with α-bromopoly(dimethylsiloxane) (PDMS) (\( \bar{M}_{\text{n}} \) = 10,000 g/mol) macroinitiator. In the second step the synthesized poly(dimethylsi...

This work deals with the synthesis and characterization of new diblock copolymers based on π-conjugated and depolymerizable units. These diblock copolymers are based on a regioregular poly(3-hexylthiophene) sequence associated with a sacrificial block, namely polyphthalaldehyde. The conjugated polymer was obtained by Grignard metathesis polymerizat...

Multifunctional materials can be engineered by combining multiple chemical components, each conferring a well-defined function to the ensemble. Graphene is at the centre of an ever-growing research effort due to its combination of unique properties. Here we show that the large conformational change associated with the trans-cis photochemical isomer...

Supplementary Figures 1-19, Supplementary Notes 1-8 and Supplementary References

The photopolymerization of acrylated oligomers dispersed in an aqueous medium is successfully demonstrated using a simple continuous photoreactor designed with flexible tubing, which presents straightforward up-scaling and maintenance features. The performance of the continuous photoreactor is assessed by varying the length of the tube exposed to u...

Conjugated graft copolymers consisting of a chiral poly(phenyleneethynylene) (PPE) backbone and poly(3-hexylthiophene) side chains (P3HT) with different grafting degrees were synthesized. While PPE was prepared by classical Sonogashira couplings, the end-functionalized P3HT was prepared by a controlled Kumada catalyst transfer polycondensation (KCT...