Research team

Nanostructured and organic optical and electronic materials (NANOrOPT)

Expertise

* Solubilization, molecular filling, and chirality sorting of carbon nanotubes (CNTs) * Spectroscopic characterization of carbon nanotubes and their nanohybrids * Design of (non-linear) optical molecules and nanomaterials * Non-linear optical characterization of organic molecules and nanomaterials

TunabLe pulsed And continuouS-wavE laseR facility (T-LASER). 01/01/2020 - 31/12/2021

Abstract

T-LASER comprises the extension of a laser facility to a versatile wavelength-tunable pulsed and continuous-wave (CW) laser platform operating from the ultraviolet to the infrared range of the optical spectrum, for enabling a wide range of advanced spectroscopic techniques and laser-based applications – the key research capabilities of the ECM group. Thanks to a large fraction (78%) of co-funding, a laser platform will be built that is not only essential to all of ECM's ongoing research projects and its many collaborations, but actually establishes a world-wide unique laser facility. Moreover, this central laser platform will be complemented with a range of optical satellite setups that are already available (and already unique) and will be further developed. The versatility of the laser facility, both in pulse duration and wavelength tunability, will enable unprecedented optical experiments, such as widely continuously tunable resonance Raman scattering, and nonlinear optical scattering such as widely wavelength-tunable (second- and third-order) hyper-Rayleigh and hyper-Raman scattering. This will form a highly complementary set of unique techniques, making UAntwerp an extremely desirable partner for research groups active in the involved technologies, worldwide.

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Chirality-defined sorting and optical characterization of double-wall carbon nanotubes. 01/10/2019 - 30/09/2022

Abstract

This is a fundamental research project financed by the Research Foundation – Flanders (FWO). The project was subsidized after selection by the FWO-expert panel. The objective of the FWO's Research projects is to advance fundamental scientific research.

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Hyperspectral imaging of the endo- and exohedral interactions of molecules with single-wall carbon nanotubes. 01/10/2019 - 30/09/2021

Abstract

This is a fundamental research project financed by the Research Foundation – Flanders (FWO). The project was subsidized after selection by the FWO-expert panel. The objective of the FWO's Research projects is to advance fundamental scientific research.

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Nonlinear Optics of Bistable Molecules and One-Dimensional Arrays. 01/01/2018 - 31/12/2021

Abstract

This is a fundamental research project financed by the Research Foundation – Flanders (FWO). The project was subsidized after selection by the FWO-expert panel. The objective of the FWO's Research projects is to advance fundamental scientific research.

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Functional Carbon Nanotube Nanohybrids: from Synthesis to Advanced Spectroscopic Characterization 01/01/2018 - 31/12/2021

Abstract

This is a fundamental research project financed by the Research Foundation – Flanders (FWO). The project was subsidized after selection by the FWO-expert panel. The objective of the FWO's Research projects is to advance fundamental scientific research.

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Carbon nanomaterial enhanced optical fibres for biomedical imaging and sensing (CHARMING). 01/01/2018 - 31/12/2021

Abstract

Optical fibres are very well-known for their application in telecommunications. In the last decades, they have also become increasingly popular in biomedical applications, where they are used as very sensitive sensors to detect minute amounts of biological cells or as flexible light sources enabling in-vivo microscopy of biological tissue, and as such allow for early diagnosis of medical conditions. At the same time, new so-called 'nanocarbon' materials with very particular characteristics have emerged, i.e. graphene and carbon nanotubes. The former is made of a sheet-like single layer of carbon atoms, whilst the latter consists of nanoscale hollow tubes rolled-up from the same carbon sheet. They both feature unique mechanical, electrical and optical properties. CHARMING's objective is to exploit these exceptional properties and to supplement them with the proven cutting-edge potential of optical fibrebased sensors and imaging systems to produce a novel class of devices for detecting and visualizing cancer cells with unprecedented sensitivity. More specifically, CHARMING will research into nanocarbon equipped optical fibres enabling the detection of down to 10 cancer cells as well as imaging of proteins in a tumorous environment with a 10-fold better sensitivity compared to current systems. By delivering this technology, CHARMING aims to contribute to the advent of advanced fibre-based tools empowering early in-vivo cancer diagnosis.

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Hyperspectral imaging of the endo- and exohedral interactions of molecules with single-wall carbon nanotubes. 01/10/2017 - 30/09/2019

Abstract

This is a fundamental research project financed by the Research Foundation – Flanders (FWO). The project was subsidized after selection by the FWO-expert panel. The objective of the FWO's Research projects is to advance fundamental scientific research.

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Synthesis, chirality sorting and advanced spectroscopy of functional nanohybrids of organic molecules inside carbon nanotubes. 01/10/2014 - 30/09/2017

Abstract

This is a fundamental research project financed by the Research Foundation – Flanders (FWO). The project was subsidized after selection by the FWO-expert panel. The objective of the FWO's Research projects is to advance fundamental scientific research.

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Equipment for high-speed refrigerated, preparative ultracentrifugation, automated gradient formation and fraction collection and analysis. 19/05/2014 - 31/12/2018

Abstract

This project represents a formal research agreement between UA and on the other hand the Hercules Foundation. UA provides the Hercules Foundation research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Nanochemistry of molecular materials for 2-photon functional applications (Nano2Fun). 01/09/2013 - 31/08/2017

Abstract

Technological development through research and knowledge transfer are the flag-words of Nano2Fun, a multidisciplinary project that will bring the techniques of two-photon microscopy (2PM) and two-photon polymerization (2PP) to their full maturity, allowing their exploitation in commercially and industrially relevant applications.

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Fully Automated Frequency Agile Characterisation of Organic Nonlinear Optical Materials 01/01/2013 - 31/12/2016

Abstract

Organic molecular materials can exhibit remarkably strong nonlinear optical (NLO) responses which are promising for photonic applications such as ultrafast electro-optic modulators and frequency converters. Most experimental work on their haracterisation and subsequent optimisation is generally limited to one or a few laser wavelengths. Yet, recent measurements on prototypical systems using our unique setup for precise and widely wavelength-tuneable incoherent second-harmonic light scattering (hyper-Rayleigh scattering, HRS) have revealed a far more complex NLO dispersion than generally assumed, implying that the almost universally applied extrapolations to the static limit (for comparison among different compounds or with theory) and to technologically relevant frequency components of the NLO response, are often off by an order of magnitude and more. Based on much more extensive wavelength dependent measurements practical yet accurate models for the NLO dispersion will be developed. To this end, we propose to lift these techniques to a new level and drastically improve the throughput of the setup, by upgrading the laser source to a fully automatically tuneable optical parametric amplifier (OPA), and integrating it with software for automatic calibration and data processing. This will allow for detailed and reliable laser-wavelength dependent NLO characterisation by hyper-Rayleigh as well as hyper-Raman scattering to be performed routinely for a wide range of systems, providing us with a solid basis for the rational design of optimised NLO materials.

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Separation, sorting and enhanced optical properties of intact carbon nanotubes and their composites. 01/01/2012 - 31/12/2015

Abstract

Carbon nanotubes (CNTs) exhibit unique and remarkably diverse electronic, optical and mechanical properties, implying potential applications ranging from ultrastrong composite materials to organic solar cells, organic light emitting diodes (O-LEDs), thin-film transistors, biomolecular sensors, nano-electro-mechanical devices (NEMS) and nanofluidic systems. This diversity in properties is at the same time a major challenge in the study and applications of CNTs, as synthesis methods produce a mixture of structures, and their virtual insolubility has long hindered their processing and purification. However, important breakthroughs have been made in our lab in the processing (by solubilization using natural bile salt surfactants), spectroscopic characterization (thanks to the high resolution achieved on the individualized, surfactant coated CNTs), and purification of CNTs (by density gradient ultracentrifugation [DGU] of the solubilized tubes). E.g., we recently demonstrated that empty (intact, end-capped) and water-filled (opened) CNTs coexist in aqueous solution, that these can be separated by DGU, and that the former posses far more ideal, unperturbed properties than the commonly used (unwittingly) water-filled tubes. All this opens a wide range of high-impact research opportunities. The empty (and full-length) CNTs allow for an enhanced further sorting according to diameter, electronic type (metallic and semiconducting), chirality, and even handedness, through density gradient ultracentrifugation. Further development of these separation/preparation methods will be combined with advanced optical spectroscopic techniques, for which our lab is particularly well equipped, to study the enhanced properties of these newly isolated intact CNTs, and their composites with organic functional molecules and polymers.

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High throughput, high performance second order light scattering spectroscopy. 01/01/2012 - 31/12/2015

Abstract

This project concerns the study of nonlineair optical response of molecules in the liquid phase, through incoherent second order light scattering using a widely wavelength tuneable picosecond amplified laser source.

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Nonlinear optical properties of single-wall carbon nanotubes and organic nanohybrids: enhancement through double resonance, coherent addition and symmetry breaking. 01/10/2011 - 30/09/2014

Abstract

Organic nonlinear optics (NLO) deals with the nonlinear response of organic molecular materials exposed to intense light beams, with prospective applications in optical telecommunication based on ultrafast switches and modulators, and highly efficient frequency convertors. In this research project, novel approaches will be examined to significantly amplify the molecular NLO response, in particular: (i) doubly (one- and twophoton) resonant enhancement, (ii) coherent addition of contributions from multiple molecular units and (iii) symmetry-breaking in formally centrosymmetric yet bistable molecules. To this aim, the NLO response of different molecular systems will be directly determined through ultrasensitive wavelength-dependent hyper-Rayleigh scattering (HRS) experiments in the appropriate wavelength ranges, using the setup I developed recently and which is unique in terms of both sensitivity and spectral tuneability. Measurements will be performed on well-designed organic molecules, as well as on single-wall carbon nanotubes (SWNTs), both empty and filled with efficient NLO chromophores. For the empty SWNTs, not only the second-order NLO response, but also the third-order response will be characterised by HRS at the tripled frequency. Finally, low-symmetry radial vibrational modes, never observed before but theoretically expected to be highly dependent on tube diameter and environmental interactions (e.g. filling), will be accessible by ultrasensitive (second- and third-order) hyper-Raman experiments.

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Advanced spectroscopy of empty and water-filled carbon nanotubes: Improved diameter sorting, exciton photophysics and one-dimensional molecular transport. 01/10/2011 - 30/09/2014

Abstract

Solubilization of single-walled carbon nanotubes (SWNTs) with bile salt surfactants allows for the sorting of the SWNTs by diameter using density gradient ultracentrifugation (DGU). Recent breakthroughs in the observation of water-filling and the sorting of empty and water-filled SWNTs will lift this sorting to a higher level, as the resolution in DGU is expected to increase drastically when using only empty and full-length SWNTs. These intact tubes possess superior optical properties, which is interesting for studying the very specific exciton photophysics of the nanotubes. The water-filling occurs even for very thin diameters, enabling the study of one-dimensional molecular transport inside the tubes and the different ordering and phase behavior of water (and other molecules) after confinement.

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Ultra-wide range wavelength dependent characterisation and modeling of organic nonlinear optical molecules. 01/01/2011 - 31/12/2013

Abstract

Recent measurements in our laboratory have shown that current models for the dispersion of the molecular nonlinear optical (NLO) response (hyperpolarisability ß), widely used in the interpretation of experimental data on organic/organometallic NLO molecules, fail at predicting the correct evolution with wavelength. This is very important to the fundamental understanding of the underlying physical mechanisms determining the NLO response, and hence also to be able to optimise the NLO molecules, and to derive the NLO response at technologically relevant frequencies ¿ and in the static limit, which is needed to compare with different molecules (showing different resonances) and with theoretical calculations. By implementing an improved detection scheme using a deep-depletion liquid nitrogen cooled CCD, and thereby significantly extending the wavelength range and sensitivity of our high performance setup for wavelength dependent hyper-Rayleigh scattering measurements (already unique in the world), we will be able to accurately measure the hyperpolarisability dispersion of representative model systems over an extremely wide wavelength range (fundamental wavelength ~400-2200nm), making optimal use of the available state-of-the-art picosecond amplified laser system. This will allow us to propose and accurately test refined models for the hyperpolarisability dispersion, properly accounting for vibronic coupling, and both homogeneous and inhomogeneous broadening effects, which play a quite different role in the NLO dispersion (unlike in linear optical properties).

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Separation and high-resolution spectroscopic characterisation of carbon nanotubes and nanocomposites. 01/01/2011 - 31/12/2011

Abstract

In order to fully exploit the exciting fundamental research opportunities created by the solubilisation/preparation techniques developed in the group, and making use of the available expertise in advanced spectroscopic research we aim at (1) Optimising the density gradient ultracentrifugation separation of different types of SWNTs by using pristine, full-length and empty SWNTs. This will involve the study of the subtle interactions of water and various surfactant molecules with the different types of SWNTs by high resolution Raman spectroscopy, in order to understand the separation mechanism and find the optimal conditions. It will of course also involve the spectroscopic characterization of the composition of the separated fractions. (2) Studying the obtained purified SWNTs using advanced optical techniques, which are not possible, or at least far less informative, for samples containing a mixture of SWNT types. This includes, for instance, ultrafast laser spectroscopy where individual types of SWNTs cannot be selectively excited in mixed samples. (3) Studying the interaction of SWNTs with other molecules in composites prepared from these separated SWNT types, which will again yield far more detailed information than current work involving mixtures of dozens of different SWNT types.

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SILASOL - New Silicon Materials for Solar Applications. 01/01/2010 - 31/12/2013

Abstract

Silicon solar cells are the work horse of the photovoltaic energy conversion from sunlight into electricity.The SILASOL project focuses on new silicon-based materials for PV applications: by changing the shape of the silicon material (thinner wafers, nanowires, ...), or the synthesis method (CVD, mechanical cleavage, ...), the "new" Si material acquires specific properties (bandgap, crystallinity, ...) that can be used advantageously for PV applications. The technology development is in Imec (Leuven), the task of the UA is the experimental and computational characterization of these advanced silicon nanostructures.

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Optical and laserspectroscopical research of organic and nanostructured materials for opto-electronic applications. 01/10/2008 - 30/09/2018

Abstract

Using advanced optical and laserspectroscopic techniques, the electronic and optical properties of carbon nanotubes (CNTs) and metal nanoparticles, as well as their organic nanohybrids, are investigated. This research aims both at the development of novel functional nanomaterials for opto-electronic applications, as well as at the development of reliable characterisation methods for these materials. In addition, organic and organometallic molecules are developed for nonlinear optics, and characterised in particular with our unique setup for wavelength dependent nonlinear optical measurements.

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Mass Transport through Carbon Nanotubes. 01/07/2008 - 31/12/2012

Abstract

Based on our recent breakthroughs in the opening/closing and water-filling of carbon nanotubes, the selective mass transport through individual types of carbon nanotubes will be characterised in view of possible applications in nanofluidics and nanofiltration.

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PolySpec - Nanostructured POLYmer phototvoltaic devices for efficient solar SPECtrum harvesting. 01/01/2008 - 31/12/2011

Abstract

The project aims at increasing the energy conversion efficiency of organic nanostructured bulk heterojunction photovoltaic devices as well as improving the stability of their nanomorphology. Progress on both fronts would allow envisaging outdoor large-scale application of these nanostructured PV-devices.

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Selective linear and nonlinear optical spectroscopy of carbon nanotubes and their interactions with organic molecules. 01/01/2007 - 31/12/2010

Abstract

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Solubilisation and purification of carbon nanotubes. 01/03/2006 - 31/12/2007

Abstract

Based on the recent discovery that bile salt surfactants are unusually efficient at solubilising individual single wall carbon nanotubes in water, and that the bile salt micelles form an unusually regular, unperturbing environment for the SWNTs, solubilisation and purification methods are developed. The goal is to produce individually isolated SWNTs in sufficient quantity and purity for spectroscopic research on liquid solutions and composites.

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Optical properties of nanostructured organic materials based on carbon nanotubes. 01/10/2005 - 30/09/2008

Abstract

The objectives of the study are: 1) To apply advanced optical techniques to the isolated CTN's in liquid and solid solution to get a better understanding of the electronic and optical properties of CNT's. 2) To develop a reliable characterization method using these optical techniques, for analyzing the composition of CNT materials. 3) To prepare composites of the individually dissolved CNT's with other molecules and polymers, and study the interactions occurring in these.

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Interaction between conjugated molecules and single-walled carbon nanotubes. 01/01/2005 - 31/12/2006

Abstract

Carbon nanotubes (CNTs) are very interesting as one-dimensional systems with metallic or semiconducting properties. The conduction and mobility of holes and electrons can be described in the same way. It is also possible to dope these nanotubes by inserting small molecules in the CNTs. These doped CNTs are very stable by exposure to air and the choice of the inserted molecule controls the degree of doping. This project will deal with two different subjects. First we will study the charge transfer from the conjugated molecules to the SW CNTs. This charge transfer is of great importance for the use of such composites in plastic solar cells. Second, we will consider doping of the CNTs by inserting different conjugated molecules inside the CNTs. Both systems wil be studied by optical spectroscopy, pulsed laserspectroscopy and electron paramagnetic resonance (EPR).

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Multi-wavelength nonlinear optical spectroscopy of organic materials. 01/10/2002 - 30/09/2005

Abstract

Organic and organometallic materials for non-linear optical (NLO) applications are investigated by non-linear and time-resolved laser spectroscopy. Molecular hyperpolarisabilities are determined, e.g. by hyper-Rayleigh scattering at variable laser wavelength with fluorescence correction through spectral analysis. Based on the experimental results, and in close collaboration with several synthesis groups, new NLO materials are developed. Also materials for two-photon absorption and two-photon induced fluorescence applications are developed.

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Nonlinear light scattering and multiphoton absorption in molecular optical materials. 01/01/2001 - 31/12/2006

Abstract

The 2nd and 3rd order nonlinear optical (NLO) properties of organic and organometallic compounds will be investigated by means of advanced spectroscopic techniques, in particular elastic and inelastic nonlinear light scattering 'hyper-Rayleigh (at the 2nd and 3rd harmonic) en hyper-Raman scattering' and also multiphoton absorption spectroscopy. To this end, a high-performance apparatus will be constructed based on a novel laser system with kilohertz repetition rate and a multi-channel detector for parallel measurement of the spectra.

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