Marek Szablewski - Academia.edu (original) (raw)

Papers by Marek Szablewski

ChemInform, Dec 12, 1989

Reaction of LiI (IV) or (MePPh3)I with dicyanomethylenedione (III), prepared by a new method from... more Reaction of LiI (IV) or (MePPh3)I with dicyanomethylenedione (III), prepared by a new method from (I) and (II), leads by way of a fascinating isomerization of the indan skeleton to the naphthoquinol salts (Va) and (Vb), respectively.

Proceedings of SPIE, Oct 5, 1995

ABSTRACT

2022 IEEE 49th Photovoltaics Specialists Conference (PVSC), Jun 5, 2022

ACS Applied Materials & Interfaces, Aug 1, 2014

Printed nanocomposites are of significant applications potential in numerous technologies, such a... more Printed nanocomposites are of significant applications potential in numerous technologies, such as touch-sensitive sensors and surfaces. Here, temperature dependent electrical transport measurements were undertaken on a recently developed screen-printed, multi-component, nanocomposite ink to develop a detailed understanding of the electrical transport mechanisms. A theoretical model combining contributions from linear percolative conduction, and non-linear conduction attributed to field-assisted quantum tunneling, successfully describes the temperature dependent conduction observed.

Materials Today: Proceedings, 2019

The eect of annealing conditions : temperature, time, ramping rate and atmosphere on nanocrystal ... more The eect of annealing conditions : temperature, time, ramping rate and atmosphere on nanocrystal Cu2ZnSnS4 (CZTS) thin lm solar cell properties.', Materials today : proceedings., 18 (2). pp. 473-486.

Springer eBooks, 1990

There is renewed interest in organic materials for optical data storage and, recently, a multifre... more There is renewed interest in organic materials for optical data storage and, recently, a multifrequency memory, comprising a Langmuir-Blodgett film with different photochromic layers, was proposed by Ando et al.1–4. To store several bits per pixel requires layers, with non-overlapping photochromic bands, which may be independently switched. The J-aggregated spiropyrans show some promise4 but their frequency range is restricted. It is necessary to design alternative materials with photochromic bands in the visible and near IR. An interesting series of photochromics, with tunable absorption bands, has been studied at Cranfield5–7. The materials are zwitterionic8 and have the general formula D+-CH=C(CN)-C6H4-C(CN)2 − where D+ is a pyridinium or quinolinium group linked at the alpha or gamma position. They may be switched at visible wavelengths and the photochromism has been attributed5,6 to electron transfer between a coloured zwitterionic form and a neutral colourless form.

Journal of Materials Chemistry C, 2016

There is much interest in the search for novel materials that show ferroelectric as well as magne... more There is much interest in the search for novel materials that show ferroelectric as well as magneto-electric coupling, such as that observed in multiferroics. Within organic based materials the electronic polarisation can originate from a charge distribution across a molecule or molecules, and so one must search for systems that have an electronic (and magnetic) dipole that is intrinsic. One such material is tetraethylammonium bis-7,7,8,8tetracyanoquinodimethane (TEA(TCNQ) 2) which is a charge transfer system with a single electron that is delocalised across a TCNQ dimer. We show that dielectric measurements yield anomalies at the cation freezing structural distortion and when singlet-triplet excitations freeze. In both cases the electric response is glassy and at low temperature the corresponding magnetic measurements evidence the strong magneto-electric coupling within the material showing scaling behaviour similar to spin glass systems.

Bulletin of the American Physical Society, Mar 3, 2015

TCNQ is a well known spin-Peierls system where a spin gap opens at 390 K due to the strong electr... more TCNQ is a well known spin-Peierls system where a spin gap opens at 390 K due to the strong electron-phonon coupling within the material, essentially forming 1D stack of antiferromagnetially coupled anion TCNQ dimers. We show that on substitution of TCNQF 4 for the TCNQ this changes the interaction of the anions and shifts T sp to 150 K. Additionally, substitution of TCNQ by TCNQBr 2 produces a sample with an even lower interaction strength. These observations demonstrate the ability to tune this system from a chemical point of view. Muon spin relaxation measurements show that in the vicinity of T sp the system is dominated by magnetic fluctuations and these persist to lower temperatures until the moments exhibit a quasi-static state on the time scale of the µSR experiment (MHz range). Within the KTCNQF4 sample we also observe the emergence of a small contribution from an entangled F-µ +-F where the data could be modeled using two environments that can help suggest possible muon stopping sites.

Magnetochemistry

Chemically altering molecules can have dramatic effects on the physical properties of a series of... more Chemically altering molecules can have dramatic effects on the physical properties of a series of very similar molecular compounds. A good example of this is within the quasi-1D spin-Peierls system potassium TCNQ (TCNQ = 7,7,8,8-tetracyanoqunidimethane), where substitution of TCNQF4 for TCNQ has a dramatic effect on the 1D interactions, resulting in a drop in the corresponding spin-Peierls transition temperature. Within this work, we extend the investigation to potassium TCNQBr2, where only two protons of TCNQ can be substituted with bromine atoms due to steric constraints. The new system exhibits evidence for a residual component of the magnetism when probed via magnetic susceptibility measurements and muon spin spectroscopy. The observations suggest that the system is dominated by short range, and potentially disordered, correlations within the bulk phase.

Optics and Photonics Journal, 2016

In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have inve... more In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have investigated the second harmonic generation (SHG) from both nonlinear polymer and guest-host thin films. We have also investigated the role of capping on the SHG, temporal stability and relaxation of dipole alignment. Corona poling techniques were employed to orient the dopants into the noncentrosymmetric structure required to obtain the SHG. The effect of capping with a polymeric encapsulant below the glass transition temperature of the polymers on the unpoled and corona poled thin films was studied. Capping of the nonlinear polymer and guest host thin films have resulted in high SHG with good temporal stability. SHG signal falls drastically during the first 8 days after poling while no further significant decay in SHG signal was observed after about 33 days. Our investigations have identified the characteristics required for a good encapsulant on a non-conductive surface.

Bulletin of the American Physical Society, Mar 17, 2016

There is much interest in the search for novel materials that show ferroelectric as well as magne... more There is much interest in the search for novel materials that show ferroelectric as well as magneto-electric coupling, such as that observed in multiferroics. Within organic based materials the electronic polarisation can come from a charge distribution across a molecule or molecules and so one must search for systems that have a electronic (and magnetic) dipole that is intrinsic. One such material is tetraethylammonium bis-7,7,8,8-tetracyanoquinodimethane (TEA(TCNQ) 2) which is a charge transfer system where there is a single electron delocalised across a TCNQ dimer. We show that dielectric measurements yield anomalies at the Peierls structural distortion and on going through the spin-Peierls transition. In both cases the electric response is glassy and at low temperature the corresponding magnetic measurements evidence the strong magneto-electric coupling within the material showing analogies to spin glass systems.

Physical Chemistry Chemical Physics, 2022

Materials research express, Feb 14, 2017

The metal-organic charge transfer compound NiTCNQ 2 has been subjected to pressure where both mag... more The metal-organic charge transfer compound NiTCNQ 2 has been subjected to pressure where both magnetisation and muon experiments show a suppression of T C with an applied pressure. At 12 kbar, it appears that the sample is paramagnetic and this gives an estimate of the pressure required for switching the transition on/off. The present work also provides some insight into the structure since this behaviour can be explained if the structure is 3D where TCNQ interactions increase along a stack with increasing pressure which causes spins on the TCNQ to couple into a singlet state with just isolated Ni ions left, which behave paramagnetically.

New Directions, 2013

T (2013) 'Using interactive screen experiments as pre-laboratory tasks to enhance student learnin... more T (2013) 'Using interactive screen experiments as pre-laboratory tasks to enhance student learning.', New directions in the teaching of physical sciences., 1 (9). pp. 24-47.

Journal of Physics: Condensed Matter, 2020

The search for ferromagnetic organic-based compounds has been a particular challenge to both chem... more The search for ferromagnetic organic-based compounds has been a particular challenge to both chemists and physicists over the past few decades. The synthesis of the Ni2A, where A is an organic acceptor; tetracyanoethene (TCNE), 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) (Jain et al 2007 Nature 445 291), was reported to be a great advancement with claims that the ferromagnetism persisted to well above room temperature. There were, however some substantial flaws in the methodology associated with the synthesis and physical characterisation. Our work solely studies the Ni2TCNQ compound where we find no evidence for the existence of inherent ferromagnetism within the material that was reported in the original paper. Instead, we find that the magnetism is due to superparamagnetic nickel nanoparticles embedded in an amorphous matrix. It is hoped that our work will also show that one must be careful when using Ni(COD)2 as a precursor in the syn...

Physical Review B, 2015

An in-depth study of the metal-organic magnet Ni(TCNQ) 2 was conducted where the deuterated form ... more An in-depth study of the metal-organic magnet Ni(TCNQ) 2 was conducted where the deuterated form was synthesised both to attempt to alter the magnetic properties of the material and to be advantageous in techniques such as neutron scattering and muon spectroscopy. Deuteration saw a 3 K increase in T C with magnetization and heat capacity measurements demonstrating a spin wave contribution at low temperatures confirming the 3D nature of the ferromagnetic state shown by Ni(TCNQ − D 4) 2. AC susceptibility results suggest there is a glassy component associated with the magnetically ordered state, though muon spectroscopy measurements did not support the presence of a spin glass state. Instead muon spectroscopy at zero magnetic field indicated the presence of two magnetic transitions, one at 20 K and another below 6 K; the latter is likely due to the system entering a quasistatic regime, similar to what one might expect of a superspin or cluster glass. Neutron diffraction measurements further supported this by revealing very weak magnetic Bragg peaks suggesting that the magnetism may have a short coherence length and be confined to small grains or clusters. The separation of the ferromagnetic and glassy magnetic components of the material's properties suggest that this system may show promise as a metal-organic magnet which is easily modified to change its magnetic properties, providing larger grain sizes can be synthesized.

Key Engineering Materials, 2015

A transparent, force sensing resistive ink suitable for touchscreen technology is presented, whic... more A transparent, force sensing resistive ink suitable for touchscreen technology is presented, which is capable of detecting both touch location and the applied force. The force sensing behavior is realized by a screen-printed ink layer which consists of pre-formed semi-conductive granules dispersed in an insulating polymer. The granule size is of a comparable dimension to the thickness of the printed layer. Conduction is via the creation of pressure-induced conductive pathways through the layer at the contact point. With increasing force the number of pathways increases and the resistance of the pathways decreases, reducing the resistance through the layer. The electrical behavior was tested with finger-press forces up to 5 N using a load cell and stylus attachment. Optical properties of the touchscreen were assessed using a spectrophotometer to measure the transmitted light over the range of visible wavelengths. Both the force-resistance profiles and the optical properties of the la...

MRS Proceedings, 1989

ABSTRACTZ-β-(N-alkyl-4-pyridinium)-α-cyano-4-styryldicyanomethanide (R-P3CNQ) and its quinolinium... more ABSTRACTZ-β-(N-alkyl-4-pyridinium)-α-cyano-4-styryldicyanomethanide (R-P3CNQ) and its quinolinium analogue (R-Q3CNQ) are photochromic. Their LB films show sharp charge transfer bands at 495 nm (C16H33-P3CNQ) , 565 nm (C16H33-Q3CNQ) and 614 nm (C8H17-Q3CNQ) with half widths at half maximum of 27, 22 and 37 nm respectively. They show interesting nonlinear optical properties and have the potential to store three bits per pixel when addressed at these wavelengths.

ChemInform, Dec 12, 1989

Reaction of LiI (IV) or (MePPh3)I with dicyanomethylenedione (III), prepared by a new method from... more Reaction of LiI (IV) or (MePPh3)I with dicyanomethylenedione (III), prepared by a new method from (I) and (II), leads by way of a fascinating isomerization of the indan skeleton to the naphthoquinol salts (Va) and (Vb), respectively.

Proceedings of SPIE, Oct 5, 1995

ABSTRACT

2022 IEEE 49th Photovoltaics Specialists Conference (PVSC), Jun 5, 2022

ACS Applied Materials & Interfaces, Aug 1, 2014

Printed nanocomposites are of significant applications potential in numerous technologies, such a... more Printed nanocomposites are of significant applications potential in numerous technologies, such as touch-sensitive sensors and surfaces. Here, temperature dependent electrical transport measurements were undertaken on a recently developed screen-printed, multi-component, nanocomposite ink to develop a detailed understanding of the electrical transport mechanisms. A theoretical model combining contributions from linear percolative conduction, and non-linear conduction attributed to field-assisted quantum tunneling, successfully describes the temperature dependent conduction observed.

Materials Today: Proceedings, 2019

The eect of annealing conditions : temperature, time, ramping rate and atmosphere on nanocrystal ... more The eect of annealing conditions : temperature, time, ramping rate and atmosphere on nanocrystal Cu2ZnSnS4 (CZTS) thin lm solar cell properties.', Materials today : proceedings., 18 (2). pp. 473-486.

Springer eBooks, 1990

There is renewed interest in organic materials for optical data storage and, recently, a multifre... more There is renewed interest in organic materials for optical data storage and, recently, a multifrequency memory, comprising a Langmuir-Blodgett film with different photochromic layers, was proposed by Ando et al.1–4. To store several bits per pixel requires layers, with non-overlapping photochromic bands, which may be independently switched. The J-aggregated spiropyrans show some promise4 but their frequency range is restricted. It is necessary to design alternative materials with photochromic bands in the visible and near IR. An interesting series of photochromics, with tunable absorption bands, has been studied at Cranfield5–7. The materials are zwitterionic8 and have the general formula D+-CH=C(CN)-C6H4-C(CN)2 − where D+ is a pyridinium or quinolinium group linked at the alpha or gamma position. They may be switched at visible wavelengths and the photochromism has been attributed5,6 to electron transfer between a coloured zwitterionic form and a neutral colourless form.

Journal of Materials Chemistry C, 2016

There is much interest in the search for novel materials that show ferroelectric as well as magne... more There is much interest in the search for novel materials that show ferroelectric as well as magneto-electric coupling, such as that observed in multiferroics. Within organic based materials the electronic polarisation can originate from a charge distribution across a molecule or molecules, and so one must search for systems that have an electronic (and magnetic) dipole that is intrinsic. One such material is tetraethylammonium bis-7,7,8,8tetracyanoquinodimethane (TEA(TCNQ) 2) which is a charge transfer system with a single electron that is delocalised across a TCNQ dimer. We show that dielectric measurements yield anomalies at the cation freezing structural distortion and when singlet-triplet excitations freeze. In both cases the electric response is glassy and at low temperature the corresponding magnetic measurements evidence the strong magneto-electric coupling within the material showing scaling behaviour similar to spin glass systems.

Bulletin of the American Physical Society, Mar 3, 2015

TCNQ is a well known spin-Peierls system where a spin gap opens at 390 K due to the strong electr... more TCNQ is a well known spin-Peierls system where a spin gap opens at 390 K due to the strong electron-phonon coupling within the material, essentially forming 1D stack of antiferromagnetially coupled anion TCNQ dimers. We show that on substitution of TCNQF 4 for the TCNQ this changes the interaction of the anions and shifts T sp to 150 K. Additionally, substitution of TCNQ by TCNQBr 2 produces a sample with an even lower interaction strength. These observations demonstrate the ability to tune this system from a chemical point of view. Muon spin relaxation measurements show that in the vicinity of T sp the system is dominated by magnetic fluctuations and these persist to lower temperatures until the moments exhibit a quasi-static state on the time scale of the µSR experiment (MHz range). Within the KTCNQF4 sample we also observe the emergence of a small contribution from an entangled F-µ +-F where the data could be modeled using two environments that can help suggest possible muon stopping sites.

Magnetochemistry

Chemically altering molecules can have dramatic effects on the physical properties of a series of... more Chemically altering molecules can have dramatic effects on the physical properties of a series of very similar molecular compounds. A good example of this is within the quasi-1D spin-Peierls system potassium TCNQ (TCNQ = 7,7,8,8-tetracyanoqunidimethane), where substitution of TCNQF4 for TCNQ has a dramatic effect on the 1D interactions, resulting in a drop in the corresponding spin-Peierls transition temperature. Within this work, we extend the investigation to potassium TCNQBr2, where only two protons of TCNQ can be substituted with bromine atoms due to steric constraints. The new system exhibits evidence for a residual component of the magnetism when probed via magnetic susceptibility measurements and muon spin spectroscopy. The observations suggest that the system is dominated by short range, and potentially disordered, correlations within the bulk phase.

Optics and Photonics Journal, 2016

In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have inve... more In attempts to fabricate thermally stable second-order nonlinear polymer thin films, we have investigated the second harmonic generation (SHG) from both nonlinear polymer and guest-host thin films. We have also investigated the role of capping on the SHG, temporal stability and relaxation of dipole alignment. Corona poling techniques were employed to orient the dopants into the noncentrosymmetric structure required to obtain the SHG. The effect of capping with a polymeric encapsulant below the glass transition temperature of the polymers on the unpoled and corona poled thin films was studied. Capping of the nonlinear polymer and guest host thin films have resulted in high SHG with good temporal stability. SHG signal falls drastically during the first 8 days after poling while no further significant decay in SHG signal was observed after about 33 days. Our investigations have identified the characteristics required for a good encapsulant on a non-conductive surface.

Bulletin of the American Physical Society, Mar 17, 2016

There is much interest in the search for novel materials that show ferroelectric as well as magne... more There is much interest in the search for novel materials that show ferroelectric as well as magneto-electric coupling, such as that observed in multiferroics. Within organic based materials the electronic polarisation can come from a charge distribution across a molecule or molecules and so one must search for systems that have a electronic (and magnetic) dipole that is intrinsic. One such material is tetraethylammonium bis-7,7,8,8-tetracyanoquinodimethane (TEA(TCNQ) 2) which is a charge transfer system where there is a single electron delocalised across a TCNQ dimer. We show that dielectric measurements yield anomalies at the Peierls structural distortion and on going through the spin-Peierls transition. In both cases the electric response is glassy and at low temperature the corresponding magnetic measurements evidence the strong magneto-electric coupling within the material showing analogies to spin glass systems.

Physical Chemistry Chemical Physics, 2022

Materials research express, Feb 14, 2017

The metal-organic charge transfer compound NiTCNQ 2 has been subjected to pressure where both mag... more The metal-organic charge transfer compound NiTCNQ 2 has been subjected to pressure where both magnetisation and muon experiments show a suppression of T C with an applied pressure. At 12 kbar, it appears that the sample is paramagnetic and this gives an estimate of the pressure required for switching the transition on/off. The present work also provides some insight into the structure since this behaviour can be explained if the structure is 3D where TCNQ interactions increase along a stack with increasing pressure which causes spins on the TCNQ to couple into a singlet state with just isolated Ni ions left, which behave paramagnetically.

New Directions, 2013

T (2013) 'Using interactive screen experiments as pre-laboratory tasks to enhance student learnin... more T (2013) 'Using interactive screen experiments as pre-laboratory tasks to enhance student learning.', New directions in the teaching of physical sciences., 1 (9). pp. 24-47.

Journal of Physics: Condensed Matter, 2020

The search for ferromagnetic organic-based compounds has been a particular challenge to both chem... more The search for ferromagnetic organic-based compounds has been a particular challenge to both chemists and physicists over the past few decades. The synthesis of the Ni2A, where A is an organic acceptor; tetracyanoethene (TCNE), 3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) (Jain et al 2007 Nature 445 291), was reported to be a great advancement with claims that the ferromagnetism persisted to well above room temperature. There were, however some substantial flaws in the methodology associated with the synthesis and physical characterisation. Our work solely studies the Ni2TCNQ compound where we find no evidence for the existence of inherent ferromagnetism within the material that was reported in the original paper. Instead, we find that the magnetism is due to superparamagnetic nickel nanoparticles embedded in an amorphous matrix. It is hoped that our work will also show that one must be careful when using Ni(COD)2 as a precursor in the syn...

Physical Review B, 2015

An in-depth study of the metal-organic magnet Ni(TCNQ) 2 was conducted where the deuterated form ... more An in-depth study of the metal-organic magnet Ni(TCNQ) 2 was conducted where the deuterated form was synthesised both to attempt to alter the magnetic properties of the material and to be advantageous in techniques such as neutron scattering and muon spectroscopy. Deuteration saw a 3 K increase in T C with magnetization and heat capacity measurements demonstrating a spin wave contribution at low temperatures confirming the 3D nature of the ferromagnetic state shown by Ni(TCNQ − D 4) 2. AC susceptibility results suggest there is a glassy component associated with the magnetically ordered state, though muon spectroscopy measurements did not support the presence of a spin glass state. Instead muon spectroscopy at zero magnetic field indicated the presence of two magnetic transitions, one at 20 K and another below 6 K; the latter is likely due to the system entering a quasistatic regime, similar to what one might expect of a superspin or cluster glass. Neutron diffraction measurements further supported this by revealing very weak magnetic Bragg peaks suggesting that the magnetism may have a short coherence length and be confined to small grains or clusters. The separation of the ferromagnetic and glassy magnetic components of the material's properties suggest that this system may show promise as a metal-organic magnet which is easily modified to change its magnetic properties, providing larger grain sizes can be synthesized.

Key Engineering Materials, 2015

A transparent, force sensing resistive ink suitable for touchscreen technology is presented, whic... more A transparent, force sensing resistive ink suitable for touchscreen technology is presented, which is capable of detecting both touch location and the applied force. The force sensing behavior is realized by a screen-printed ink layer which consists of pre-formed semi-conductive granules dispersed in an insulating polymer. The granule size is of a comparable dimension to the thickness of the printed layer. Conduction is via the creation of pressure-induced conductive pathways through the layer at the contact point. With increasing force the number of pathways increases and the resistance of the pathways decreases, reducing the resistance through the layer. The electrical behavior was tested with finger-press forces up to 5 N using a load cell and stylus attachment. Optical properties of the touchscreen were assessed using a spectrophotometer to measure the transmitted light over the range of visible wavelengths. Both the force-resistance profiles and the optical properties of the la...

MRS Proceedings, 1989

ABSTRACTZ-β-(N-alkyl-4-pyridinium)-α-cyano-4-styryldicyanomethanide (R-P3CNQ) and its quinolinium... more ABSTRACTZ-β-(N-alkyl-4-pyridinium)-α-cyano-4-styryldicyanomethanide (R-P3CNQ) and its quinolinium analogue (R-Q3CNQ) are photochromic. Their LB films show sharp charge transfer bands at 495 nm (C16H33-P3CNQ) , 565 nm (C16H33-Q3CNQ) and 614 nm (C8H17-Q3CNQ) with half widths at half maximum of 27, 22 and 37 nm respectively. They show interesting nonlinear optical properties and have the potential to store three bits per pixel when addressed at these wavelengths.