Polyurethane-based nanocomposite films were prepared by incorporating carbon-coated SiC nanowires... more Polyurethane-based nanocomposite films were prepared by incorporating carbon-coated SiC nanowires (SiC@C) into the polymer matrix. Electric field-induced strain measurements revealed that a loading of 0.5 wt% SiC@C increased the strain level by a factor of 1.7 at a moderate field strength (6.5 V µm-1). Current-electric field characteristics and the film thickness dependence of strain demonstrated that the improvement of the
ABSTRACT A gradual downshift and broadening of the Si optical phonon peak was observed by Raman s... more ABSTRACT A gradual downshift and broadening of the Si optical phonon peak was observed by Raman scattering measurements on individual undoped and p-doped silicon nanowire (SiNW) when heated by a laser beam. This dual effect can be interpreted by an induced compressive stress resulting from structural defects. The p-doped SiNW was shown to be the most sensitive to heating and its structure was clearly modified with a large diffusion of gold atoms forming numerous gold nanoparticles.
Materials Research Society symposia proceedings. Materials Research Society
Macrocyclic thiacalixarenes have interesting non-linear optical properties. Thiacalixarenes beari... more Macrocyclic thiacalixarenes have interesting non-linear optical properties. Thiacalixarenes bearing phenylazo, imino, ethynylic groups or platinum derived acetylides on the upper rims were designed, prepared and fully characterised. They showed interesting properties for optical limiting. Moreover these macrocycles are highly soluble in organic solvents and can easily be embedded in inorganic matrix using the sol-gel routes. Thiacalixarene based class I and II solid-state materials were prepared and their optical limiting behaviour was investigated.
ABSTRACT Grafting of polystyrene (PS) from silica coating of silicon nanowires (SiNWs) has improv... more ABSTRACT Grafting of polystyrene (PS) from silica coating of silicon nanowires (SiNWs) has improved the dispersion of SiNWs in poly(N-vinylcarbazole) (PVK) matrix to form a bulk heterojunction (BHJ) hybrid photovoltaic (HPV) cell. First, an alkoxyamine, based on N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl) nitroxide (DEPN) was covalently attached onto SiNWs through free surface silanol groups. Then, polystyrene chains with controlled molecular weights and narrow polydispersities were grown from the alkoxyamine-functionalized SiNWs surface in the presence of a “free” sacrificial styrylDEPN alkoxyamine. Both the initiator and the polystyrene chains were characterized by FTIR and 13C Solid-State NMR and quantified by TGA. The hybrid layer of SiNWs and PVK, results in cell performance improvement in respect to a reference cell based on PVK alone. A fill factor of 50% is achieved upon inclusion of PS grafted SiNWs.
Polyurethane-based nanocomposite films were prepared by incorporating carbon-coated SiC nanowires... more Polyurethane-based nanocomposite films were prepared by incorporating carbon-coated SiC nanowires (SiC@C) into the polymer matrix. Electric field-induced strain measurements revealed that a loading of 0.5 wt% SiC@C increased the strain level by a factor of 1.7 at a moderate field strength (6.5 V µm-1). Current-electric field characteristics and the film thickness dependence of strain demonstrated that the improvement of the
ABSTRACT A gradual downshift and broadening of the Si optical phonon peak was observed by Raman s... more ABSTRACT A gradual downshift and broadening of the Si optical phonon peak was observed by Raman scattering measurements on individual undoped and p-doped silicon nanowire (SiNW) when heated by a laser beam. This dual effect can be interpreted by an induced compressive stress resulting from structural defects. The p-doped SiNW was shown to be the most sensitive to heating and its structure was clearly modified with a large diffusion of gold atoms forming numerous gold nanoparticles.
Materials Research Society symposia proceedings. Materials Research Society
Macrocyclic thiacalixarenes have interesting non-linear optical properties. Thiacalixarenes beari... more Macrocyclic thiacalixarenes have interesting non-linear optical properties. Thiacalixarenes bearing phenylazo, imino, ethynylic groups or platinum derived acetylides on the upper rims were designed, prepared and fully characterised. They showed interesting properties for optical limiting. Moreover these macrocycles are highly soluble in organic solvents and can easily be embedded in inorganic matrix using the sol-gel routes. Thiacalixarene based class I and II solid-state materials were prepared and their optical limiting behaviour was investigated.
ABSTRACT Grafting of polystyrene (PS) from silica coating of silicon nanowires (SiNWs) has improv... more ABSTRACT Grafting of polystyrene (PS) from silica coating of silicon nanowires (SiNWs) has improved the dispersion of SiNWs in poly(N-vinylcarbazole) (PVK) matrix to form a bulk heterojunction (BHJ) hybrid photovoltaic (HPV) cell. First, an alkoxyamine, based on N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl) nitroxide (DEPN) was covalently attached onto SiNWs through free surface silanol groups. Then, polystyrene chains with controlled molecular weights and narrow polydispersities were grown from the alkoxyamine-functionalized SiNWs surface in the presence of a “free” sacrificial styrylDEPN alkoxyamine. Both the initiator and the polystyrene chains were characterized by FTIR and 13C Solid-State NMR and quantified by TGA. The hybrid layer of SiNWs and PVK, results in cell performance improvement in respect to a reference cell based on PVK alone. A fill factor of 50% is achieved upon inclusion of PS grafted SiNWs.
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Papers by David Cornu