Prof. Dr. Jonathan De Roo Department of Chemistry Profiles & Affiliations OverviewResearch Publications Projects & Collaborations Projects & Collaborations OverviewResearch Publications Projects & Collaborations Profiles & Affiliations Projects & Collaborations 5 foundShow per page10 10 20 50 Recyclable porous catalysts from metal oxo clusters Research Project | 1 Project MembersImported from Grants Tool 4657754 Unlocking complex ceramic nanocrystals using kinetic control and mechanistic insight Research Project | 3 Project MembersBackground. Colloidal (= non-aggregated) metal oxide and nitride nanocrystals (NCs) based on group 4 metals (Ti, Zr, Hf), are an underdeveloped materials class. However, they have the potential to play a central role in cancer therapy, bio-imaging, catalysis, memory devices, smart windows, ferroelectrics, solar cells, batteries, etc. They are nontoxic and chemically and thermally stable (= ceramic), key attributes for their successful application. However, the current synthetic methods towards the oxide NCs lack control over size, composition and structure while the colloidal nitride NCs are completely elusive. In addition, there is little mechanistic insight in the syntheses that do produce high quality metal oxide NCs. While the analysis of kinetics is usually the key to uncovering reaction mechanisms, the case of colloidal NCs is difficult because there are hundreds of elementary steps involved. Changes in precursor concentration or temperature do not only affect the kinetics of the first step (precursor conversion) but also influence the rates of nucleation and growth of the crystals.Goals and methods. My hypothesis is that well-defined, tunable precursors will provide an orthogonal handle on the kinetics of metal oxide and metal nitride NC formation. This is key to our general objective of obtaining mechanistic insight in and control over the formation of complex ceramic NCs. The project has four specific aims:1.We design a series of metal complexes as precursors with tunable conversion kinetics. Our first targets are the binary oxide and nitride NCs of Ti, Zr and Hf via a surfactant assisted approach. 2.We employ the tunable precursors to investigate the mechanism of NC formation. We aim to elucidate the precursor decomposition and the crystallization mechanism, and build a theoretical framework.3.We aim to apply our kinetic control and mechanistic insight to synthesize complex ceramic NCs. To demonstrate the power of our approach, we target highly challenging metal oxides: doped NCs, core/shell architectures and ternary compositions. 4.Finally, we focus on multimetal metal nitrides.Impact. Nanomaterial synthesis does not yet feature the predictability, reproducibility and intricacy of organic synthesis but this project aspires to be a step along the way toward this goal. If successful, it will change the way ceramic NCs are synthesized, going from an ad hoc, trial-and-error approach to a rational design. In addition, this project will provide exciting, previously inaccessible metal oxide building blocks for material science and nanomedicine. Finally, this project will break open a new field: colloidal metal nitrides. X-ray Diffractometer for Pair Distribution Function analysis of nanocrystals and nanostructured materials Research Project | 3 Project MembersNanoscience is at the frontier of research and is expected to provide new solutions in healthcare and energy. However, nanostructured materials in general and nanocrystals (NCs) in particular present a challenging problem: their structure is difficult to analyze with conventional techniques. Whereas powder X-ray diffraction (XRD) is very powerful for micron-sized crystals, extreme peak broadening precludes the accurate analysis of nanomaterials. As a consequence, structure-function relationships are hard to establish. Recently, a new technique has emerged, X-ray Pair Distribution Function (PDF) analysis, which allows to accurately model nanostructured materials. This requires a specialized diffractometer with high energy X-rays and a sensitive detection system. Many Swiss research groups are involved in nanostructured materials, including the main applicant, who was recently appointed as an assistant professor in nanomaterials with a research program featuring the synthesis and characterization of ceramic NCs. However, Switzerland does not yet have a PDF diffractometer available, hampering Swiss nanoscience. Therefore, we request here a PDF diffractometer with a silver source that yields the highest data quality possible for a lab diffractometer within a reasonable time (6 hours per sample). With the requested diffractometer the main applicant will pursue several projects, both fundamental and applied. In the first three projects, the PDF method will be further improved by designing new PDF sample preparation techniques for colloidal NCs (increasing signal-to-noise and removing background scattering), implementing advanced modelling and integrating PDF with other analytical techniques. This will greatly advance the use of lab source PDF diffractometers and establish PDF as a standard technique for NCs. In the second triad of projects, the main applicant will use PDF to support synthetic projects where the chemistry of (doped) metal oxide NCs is developed for bio-imaging applications and applied to shelling semiconductors NCs for solid state lighting applications. Together with the co-applicants and (inter)national collaborators, projects in the field of solar cells, photo-catalysis and thermoelectrics will be pursued. In these projects, the nanoparticle building blocks will be analyzed with the requested equipment and grant insight in their performance. Development of Nanocrystals as Artificial Mitochondria in Molecular Factories Research Project | 2 Project MembersEnergy conversion systems are a prerequisite to fuel top-down fabricated molecular factories. Such systems are the power plants of the factory and are thus equivalent to mitochondria in cells. Systems with colloidal nanocrystals at their hearth are very promising in this regard. Artificial photosynthesis, where light is converted in chemical energy, is catalysed by semiconducting nanocrystals. On the other hand, plasmonic nanocrystals can directly convert light into heat, thereby very locally raising the temperature. Such a mechanism is intensely researched for photodynamic therapy of cancer or to catalyse chemical reactions. Current challenges in photodynamic therapy include delivery of the particles to the tumour, a hurdle that is ascribed to poorly controlled surface chemistry. To incorporate nanocrystal based energy conversion systems in complex molecular factories, the toxicity and cost of the currently used semiconductor nanocrystals (cadmium or lead based) or plasmonic nanocrystals (noble metal based) must be tackled and the nanocrystals must be immobilized in the reaction compartments of the solid state platform developed in WP1 of the NCCR Molecular Systems Engineering. The latter requires a double surface functionalization, connecting the surface of both the nanocrystals and the reaction compartment. A limitation in studying the surface functionalization of the reactor compartments, is the challenging characterization of the solid state. However, nanocrystals of a few nanometer in diameter are ideally suited as model systems to study the interaction of organic molecules with metal, oxide or nitride surfaces through solution NMR techniques. The PI has already demonstrated this for carboxylic acid, phosphonic acid and diphosphoric acids ligands on CdSe, HfO 2 and CsPbBr 3 surfaces. Here, we introduce novel plasmonic nanocrystals based on nontoxic and earth abundant titanium nitride (TiN). TiN is often cited as a sustainable replacement for gold, with the additional advantage of displaying activity in the near infra-red. This opens up opportunities for photodynamic therapy of cancer cells using IR light, with deeper penetration in tissue. Furthermore, we functionalize oxide and nitride nanocrystals with tailor-made ligands that have a high binding affinity and tunable functionality. Such ligands facilitate targeted delivery for photodynamic therapy and also make it possible to couple nanocrystals to the reactor compartments. NCCR Molecular Systems Engineering - phase 2 Research Project | 30 Project MembersMolecular Systems Engineering is a National Centre of Competence in Research (NCCR) funded by the Swiss National Science Foundation (SNSF), and headed by the University of Basel and the ETH Zurich. This NCCR combines expertise from chemistry, biology, physics, bioinformatics, and engineering. The overreaching aim is to develop tools and devices to monitor and manipulate off-equilibrium (bio)chemical systems. These may find applications in the synthesis of high added-value products, as innovative diagnostic tools and for the restoration of a desired cellular or organ function. 1 1 OverviewResearch Publications Projects & Collaborations
Projects & Collaborations 5 foundShow per page10 10 20 50 Recyclable porous catalysts from metal oxo clusters Research Project | 1 Project MembersImported from Grants Tool 4657754 Unlocking complex ceramic nanocrystals using kinetic control and mechanistic insight Research Project | 3 Project MembersBackground. Colloidal (= non-aggregated) metal oxide and nitride nanocrystals (NCs) based on group 4 metals (Ti, Zr, Hf), are an underdeveloped materials class. However, they have the potential to play a central role in cancer therapy, bio-imaging, catalysis, memory devices, smart windows, ferroelectrics, solar cells, batteries, etc. They are nontoxic and chemically and thermally stable (= ceramic), key attributes for their successful application. However, the current synthetic methods towards the oxide NCs lack control over size, composition and structure while the colloidal nitride NCs are completely elusive. In addition, there is little mechanistic insight in the syntheses that do produce high quality metal oxide NCs. While the analysis of kinetics is usually the key to uncovering reaction mechanisms, the case of colloidal NCs is difficult because there are hundreds of elementary steps involved. Changes in precursor concentration or temperature do not only affect the kinetics of the first step (precursor conversion) but also influence the rates of nucleation and growth of the crystals.Goals and methods. My hypothesis is that well-defined, tunable precursors will provide an orthogonal handle on the kinetics of metal oxide and metal nitride NC formation. This is key to our general objective of obtaining mechanistic insight in and control over the formation of complex ceramic NCs. The project has four specific aims:1.We design a series of metal complexes as precursors with tunable conversion kinetics. Our first targets are the binary oxide and nitride NCs of Ti, Zr and Hf via a surfactant assisted approach. 2.We employ the tunable precursors to investigate the mechanism of NC formation. We aim to elucidate the precursor decomposition and the crystallization mechanism, and build a theoretical framework.3.We aim to apply our kinetic control and mechanistic insight to synthesize complex ceramic NCs. To demonstrate the power of our approach, we target highly challenging metal oxides: doped NCs, core/shell architectures and ternary compositions. 4.Finally, we focus on multimetal metal nitrides.Impact. Nanomaterial synthesis does not yet feature the predictability, reproducibility and intricacy of organic synthesis but this project aspires to be a step along the way toward this goal. If successful, it will change the way ceramic NCs are synthesized, going from an ad hoc, trial-and-error approach to a rational design. In addition, this project will provide exciting, previously inaccessible metal oxide building blocks for material science and nanomedicine. Finally, this project will break open a new field: colloidal metal nitrides. X-ray Diffractometer for Pair Distribution Function analysis of nanocrystals and nanostructured materials Research Project | 3 Project MembersNanoscience is at the frontier of research and is expected to provide new solutions in healthcare and energy. However, nanostructured materials in general and nanocrystals (NCs) in particular present a challenging problem: their structure is difficult to analyze with conventional techniques. Whereas powder X-ray diffraction (XRD) is very powerful for micron-sized crystals, extreme peak broadening precludes the accurate analysis of nanomaterials. As a consequence, structure-function relationships are hard to establish. Recently, a new technique has emerged, X-ray Pair Distribution Function (PDF) analysis, which allows to accurately model nanostructured materials. This requires a specialized diffractometer with high energy X-rays and a sensitive detection system. Many Swiss research groups are involved in nanostructured materials, including the main applicant, who was recently appointed as an assistant professor in nanomaterials with a research program featuring the synthesis and characterization of ceramic NCs. However, Switzerland does not yet have a PDF diffractometer available, hampering Swiss nanoscience. Therefore, we request here a PDF diffractometer with a silver source that yields the highest data quality possible for a lab diffractometer within a reasonable time (6 hours per sample). With the requested diffractometer the main applicant will pursue several projects, both fundamental and applied. In the first three projects, the PDF method will be further improved by designing new PDF sample preparation techniques for colloidal NCs (increasing signal-to-noise and removing background scattering), implementing advanced modelling and integrating PDF with other analytical techniques. This will greatly advance the use of lab source PDF diffractometers and establish PDF as a standard technique for NCs. In the second triad of projects, the main applicant will use PDF to support synthetic projects where the chemistry of (doped) metal oxide NCs is developed for bio-imaging applications and applied to shelling semiconductors NCs for solid state lighting applications. Together with the co-applicants and (inter)national collaborators, projects in the field of solar cells, photo-catalysis and thermoelectrics will be pursued. In these projects, the nanoparticle building blocks will be analyzed with the requested equipment and grant insight in their performance. Development of Nanocrystals as Artificial Mitochondria in Molecular Factories Research Project | 2 Project MembersEnergy conversion systems are a prerequisite to fuel top-down fabricated molecular factories. Such systems are the power plants of the factory and are thus equivalent to mitochondria in cells. Systems with colloidal nanocrystals at their hearth are very promising in this regard. Artificial photosynthesis, where light is converted in chemical energy, is catalysed by semiconducting nanocrystals. On the other hand, plasmonic nanocrystals can directly convert light into heat, thereby very locally raising the temperature. Such a mechanism is intensely researched for photodynamic therapy of cancer or to catalyse chemical reactions. Current challenges in photodynamic therapy include delivery of the particles to the tumour, a hurdle that is ascribed to poorly controlled surface chemistry. To incorporate nanocrystal based energy conversion systems in complex molecular factories, the toxicity and cost of the currently used semiconductor nanocrystals (cadmium or lead based) or plasmonic nanocrystals (noble metal based) must be tackled and the nanocrystals must be immobilized in the reaction compartments of the solid state platform developed in WP1 of the NCCR Molecular Systems Engineering. The latter requires a double surface functionalization, connecting the surface of both the nanocrystals and the reaction compartment. A limitation in studying the surface functionalization of the reactor compartments, is the challenging characterization of the solid state. However, nanocrystals of a few nanometer in diameter are ideally suited as model systems to study the interaction of organic molecules with metal, oxide or nitride surfaces through solution NMR techniques. The PI has already demonstrated this for carboxylic acid, phosphonic acid and diphosphoric acids ligands on CdSe, HfO 2 and CsPbBr 3 surfaces. Here, we introduce novel plasmonic nanocrystals based on nontoxic and earth abundant titanium nitride (TiN). TiN is often cited as a sustainable replacement for gold, with the additional advantage of displaying activity in the near infra-red. This opens up opportunities for photodynamic therapy of cancer cells using IR light, with deeper penetration in tissue. Furthermore, we functionalize oxide and nitride nanocrystals with tailor-made ligands that have a high binding affinity and tunable functionality. Such ligands facilitate targeted delivery for photodynamic therapy and also make it possible to couple nanocrystals to the reactor compartments. NCCR Molecular Systems Engineering - phase 2 Research Project | 30 Project MembersMolecular Systems Engineering is a National Centre of Competence in Research (NCCR) funded by the Swiss National Science Foundation (SNSF), and headed by the University of Basel and the ETH Zurich. This NCCR combines expertise from chemistry, biology, physics, bioinformatics, and engineering. The overreaching aim is to develop tools and devices to monitor and manipulate off-equilibrium (bio)chemical systems. These may find applications in the synthesis of high added-value products, as innovative diagnostic tools and for the restoration of a desired cellular or organ function. 1 1
Recyclable porous catalysts from metal oxo clusters Research Project | 1 Project MembersImported from Grants Tool 4657754
Unlocking complex ceramic nanocrystals using kinetic control and mechanistic insight Research Project | 3 Project MembersBackground. Colloidal (= non-aggregated) metal oxide and nitride nanocrystals (NCs) based on group 4 metals (Ti, Zr, Hf), are an underdeveloped materials class. However, they have the potential to play a central role in cancer therapy, bio-imaging, catalysis, memory devices, smart windows, ferroelectrics, solar cells, batteries, etc. They are nontoxic and chemically and thermally stable (= ceramic), key attributes for their successful application. However, the current synthetic methods towards the oxide NCs lack control over size, composition and structure while the colloidal nitride NCs are completely elusive. In addition, there is little mechanistic insight in the syntheses that do produce high quality metal oxide NCs. While the analysis of kinetics is usually the key to uncovering reaction mechanisms, the case of colloidal NCs is difficult because there are hundreds of elementary steps involved. Changes in precursor concentration or temperature do not only affect the kinetics of the first step (precursor conversion) but also influence the rates of nucleation and growth of the crystals.Goals and methods. My hypothesis is that well-defined, tunable precursors will provide an orthogonal handle on the kinetics of metal oxide and metal nitride NC formation. This is key to our general objective of obtaining mechanistic insight in and control over the formation of complex ceramic NCs. The project has four specific aims:1.We design a series of metal complexes as precursors with tunable conversion kinetics. Our first targets are the binary oxide and nitride NCs of Ti, Zr and Hf via a surfactant assisted approach. 2.We employ the tunable precursors to investigate the mechanism of NC formation. We aim to elucidate the precursor decomposition and the crystallization mechanism, and build a theoretical framework.3.We aim to apply our kinetic control and mechanistic insight to synthesize complex ceramic NCs. To demonstrate the power of our approach, we target highly challenging metal oxides: doped NCs, core/shell architectures and ternary compositions. 4.Finally, we focus on multimetal metal nitrides.Impact. Nanomaterial synthesis does not yet feature the predictability, reproducibility and intricacy of organic synthesis but this project aspires to be a step along the way toward this goal. If successful, it will change the way ceramic NCs are synthesized, going from an ad hoc, trial-and-error approach to a rational design. In addition, this project will provide exciting, previously inaccessible metal oxide building blocks for material science and nanomedicine. Finally, this project will break open a new field: colloidal metal nitrides.
X-ray Diffractometer for Pair Distribution Function analysis of nanocrystals and nanostructured materials Research Project | 3 Project MembersNanoscience is at the frontier of research and is expected to provide new solutions in healthcare and energy. However, nanostructured materials in general and nanocrystals (NCs) in particular present a challenging problem: their structure is difficult to analyze with conventional techniques. Whereas powder X-ray diffraction (XRD) is very powerful for micron-sized crystals, extreme peak broadening precludes the accurate analysis of nanomaterials. As a consequence, structure-function relationships are hard to establish. Recently, a new technique has emerged, X-ray Pair Distribution Function (PDF) analysis, which allows to accurately model nanostructured materials. This requires a specialized diffractometer with high energy X-rays and a sensitive detection system. Many Swiss research groups are involved in nanostructured materials, including the main applicant, who was recently appointed as an assistant professor in nanomaterials with a research program featuring the synthesis and characterization of ceramic NCs. However, Switzerland does not yet have a PDF diffractometer available, hampering Swiss nanoscience. Therefore, we request here a PDF diffractometer with a silver source that yields the highest data quality possible for a lab diffractometer within a reasonable time (6 hours per sample). With the requested diffractometer the main applicant will pursue several projects, both fundamental and applied. In the first three projects, the PDF method will be further improved by designing new PDF sample preparation techniques for colloidal NCs (increasing signal-to-noise and removing background scattering), implementing advanced modelling and integrating PDF with other analytical techniques. This will greatly advance the use of lab source PDF diffractometers and establish PDF as a standard technique for NCs. In the second triad of projects, the main applicant will use PDF to support synthetic projects where the chemistry of (doped) metal oxide NCs is developed for bio-imaging applications and applied to shelling semiconductors NCs for solid state lighting applications. Together with the co-applicants and (inter)national collaborators, projects in the field of solar cells, photo-catalysis and thermoelectrics will be pursued. In these projects, the nanoparticle building blocks will be analyzed with the requested equipment and grant insight in their performance.
Development of Nanocrystals as Artificial Mitochondria in Molecular Factories Research Project | 2 Project MembersEnergy conversion systems are a prerequisite to fuel top-down fabricated molecular factories. Such systems are the power plants of the factory and are thus equivalent to mitochondria in cells. Systems with colloidal nanocrystals at their hearth are very promising in this regard. Artificial photosynthesis, where light is converted in chemical energy, is catalysed by semiconducting nanocrystals. On the other hand, plasmonic nanocrystals can directly convert light into heat, thereby very locally raising the temperature. Such a mechanism is intensely researched for photodynamic therapy of cancer or to catalyse chemical reactions. Current challenges in photodynamic therapy include delivery of the particles to the tumour, a hurdle that is ascribed to poorly controlled surface chemistry. To incorporate nanocrystal based energy conversion systems in complex molecular factories, the toxicity and cost of the currently used semiconductor nanocrystals (cadmium or lead based) or plasmonic nanocrystals (noble metal based) must be tackled and the nanocrystals must be immobilized in the reaction compartments of the solid state platform developed in WP1 of the NCCR Molecular Systems Engineering. The latter requires a double surface functionalization, connecting the surface of both the nanocrystals and the reaction compartment. A limitation in studying the surface functionalization of the reactor compartments, is the challenging characterization of the solid state. However, nanocrystals of a few nanometer in diameter are ideally suited as model systems to study the interaction of organic molecules with metal, oxide or nitride surfaces through solution NMR techniques. The PI has already demonstrated this for carboxylic acid, phosphonic acid and diphosphoric acids ligands on CdSe, HfO 2 and CsPbBr 3 surfaces. Here, we introduce novel plasmonic nanocrystals based on nontoxic and earth abundant titanium nitride (TiN). TiN is often cited as a sustainable replacement for gold, with the additional advantage of displaying activity in the near infra-red. This opens up opportunities for photodynamic therapy of cancer cells using IR light, with deeper penetration in tissue. Furthermore, we functionalize oxide and nitride nanocrystals with tailor-made ligands that have a high binding affinity and tunable functionality. Such ligands facilitate targeted delivery for photodynamic therapy and also make it possible to couple nanocrystals to the reactor compartments.
NCCR Molecular Systems Engineering - phase 2 Research Project | 30 Project MembersMolecular Systems Engineering is a National Centre of Competence in Research (NCCR) funded by the Swiss National Science Foundation (SNSF), and headed by the University of Basel and the ETH Zurich. This NCCR combines expertise from chemistry, biology, physics, bioinformatics, and engineering. The overreaching aim is to develop tools and devices to monitor and manipulate off-equilibrium (bio)chemical systems. These may find applications in the synthesis of high added-value products, as innovative diagnostic tools and for the restoration of a desired cellular or organ function.
