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1.
Trace Detection and Photothermal Spectral Characterization by a Tuneable Thermal Lens Spectrometer with White-Light Excitation
Mladen Franko, Dorota Korte, Humberto Cabrera, 2018, original scientific article

Abstract: In the thermal lens experimental set-up we replaced the commonly employed pump laser by a halogen lamp, combined with an interference lter, providing a tuneable, nearly monochromatic pump source over the range of wavelengths 430–710 nm. Counter-propagating pump and probe beams are used and a 1 mm path-length sam- ple cell together with the interference lter makes an optical cavity, providing ampli cation of the thermal lens signal, which leads to enhancement of the measurement sensitivity, and enables detection of absorbances on the order of 5×10− 6. Ampli ed thermal lens signal allows us to replace the typical lock-in ampli er and digital os- cilloscope with a silicon photodetector, Arduino board, and a personal computer, offering the possibility for a compact, robust and portable device, useful for in- eld absorption measurements in low concentration or weakly absorbing species. The use of a white light source for optical pumping, an interference lter for wavelength selection and direct diagnostic of the thermal lens signal increase the versatility of the instrument and simpli- es substantially the experimental setup. Determination of Fe(II) concentrations at parts per billion levels was performed by the described white-light thermal lens spectrophotometer and the absorption spectrum for 50μg/ L Fe(II)-1,10-phenanthroline was well reproduced with an average measurement precision of 4%. The obtained limits of detection and quantitation of Fe(II) determination at 510nm are 3μgL− 1 and 11μgL− 1, respectively. The calibration curve was linear in the concentration range of LOQ-500μgL− 1 with reproducibility between 2% and 6%, con rming that this instrument provides good spectrometric capabilities such as high sensitivity, tune- ability and good reproducibility. In addition, the versatility of the instrument was demonstrated by recording the photothermal spectrum of gold nanostructured material and determination of excitation wavelength with most ef cient optical to thermal energy conversion, which differs considerably (cca 100 nm) from the absorption maximum of the investigated sample.
Found in: ključnih besedah
Summary of found: ...thermal lens spectrometry, Fe(II) determination, photothermal technique, multi-wavelength excitation...
Keywords: thermal lens spectrometry, Fe(II) determination, photothermal technique, multi-wavelength excitation
Published: 21.02.2018; Views: 2872; Downloads: 0
.pdf Fulltext (889,82 KB)

2.
Photocatalytic properties of metal modified TiO2 by photothermal techniques
Mladen Franko, Dorota Korte, Urška Lavrenčič Štangar, Olena Pliekhova, Humberto Cabrera, Zeinab Ebrahimpour, 2018, published scientific conference contribution abstract

Found in: ključnih besedah
Summary of found: ... Thermal lens spectrometry, Photothermal beam deflection spectroscopy, Dye... ...Photothermal beam deflection spectroscopy, Dye remediation, Photothermal technique, Photocatalytic degradation, Reactive Blue 19, TiO2 modification...
Keywords: Thermal lens spectrometry, Photothermal beam deflection spectroscopy, Dye remediation, Photothermal technique, Photocatalytic degradation, Reactive Blue 19, TiO2 modification
Published: 09.11.2018; Views: 2436; Downloads: 0
.pdf Fulltext (208,76 KB)

3.
Chemical (in)stability of interfaces between different metals and Bi[sub]2Se[sub]3 topological insulator
Sandra Gardonio, Matjaž Valant, Katja Ferfolja, Mattia Fanetti, 2018, published scientific conference contribution abstract

Abstract: In recent years a classification of materials based on their topological order gained popularity due to the discovery of materials with special topological character – topological insulators (TI). TI have different band structure than regular insulators or conductors. They are characterized by a band gap in the bulk of the material, but at the surface they possess conductive topological surface states (TSS) that cross the Fermi level. TSS are a consequence of the non-trivial bulk band structure and have properties that differ from ordinary surface states. They are robust toward contamination and deformation of the surface. Additionally, they are also spin polarized, which means that an electron spin is locked to a crystal momentum and, therefore, backscattering during transport is suppressed [1]. Due to their specific properties the TI could be used in fields of spintronics, quantum computing and catalysis [2]. The investigation of the interfaces between metals and the TI has not been given much attention even though its characterization is interesting from fundamental physics and applicative point of view. (In)stability of the contacts with metal electrodes, in a form of a chemical reaction or diffusion, has to be taken into account since it can affect the transport properties of the material or increase the contact resistance. Our research is dedicated to the study of the metal/TI interfaces, in particular to Bi2Se3 with deposited metals that are relevant for electrical contacts (Au, Ag, Pt, Cr, Ti). The thermal and chemical stability of the interfaces are of fundamental importance for understanding the contact behavior, therefore, we focused our work to the characterization of these properties. The metal/TI interfaces are investigated mainly with an electron microscopy (SEM, TEM, STM), EDX microanalysis and XRD. Our previous studies showed that the interface between Bi2Se3, and Ag deposited either chemically or from a vapor phase, results in the formation of new phases already at room temperature [3]. On the contrary, Au deposited on the Bi2Se3 surface shows very limited reactivity and is stable at RT, but diffusion and coalescence of the metal are observed starting from 100 °C [4]. In this contribution, we will present further characterization on the evolution of the Ag/Bi2Se3 and Au/Bi2Se3 interfaces, show preliminary results about recently investigated systems (Pt/Bi2Se3, Ti/Bi2Se3) and compare the thermal and chemical stability of the systems under investigation.
Found in: ključnih besedah
Summary of found: ...contacts (Au, Ag, Pt, Cr, Ti). The thermal and chemical stability of the interfaces are... ...thermal lens spectrometry, photothermal beam deflection spectroscopy, dye remediation,... ...photothermal beam deflection spectroscopy, dye remediation, photothermal technique, photocatalytic degradation, reactive blue 19, TiO2 modification...
Keywords: thermal lens spectrometry, photothermal beam deflection spectroscopy, dye remediation, photothermal technique, photocatalytic degradation, reactive blue 19, TiO2 modification
Published: 20.08.2021; Views: 978; Downloads: 0
.pdf Fulltext (100,42 KB)

4.
5.
Nondestructive evaluation of heat trap mechanism in coconut oil – A thermal lens study
SWAPNA MOHANACHANDRAN NAIR SINDHU, 2018, original scientific article

Found in: ključnih besedah
Summary of found: ...thermal energy storage, thermal diffusivity, thermal lens technique, coconut oil, nondestructive evaluation...
Keywords: thermal energy storage, thermal diffusivity, thermal lens technique, coconut oil, nondestructive evaluation
Published: 05.07.2022; Views: 89; Downloads: 0
.pdf Fulltext (1,10 MB)

6.
Effect of duty cycle on photothermal phenomenon – a thermal lens study
SWAPNA MOHANACHANDRAN NAIR SINDHU, 2019, original scientific article

Found in: ključnih besedah
Summary of found: ...Photothermal phenomena Thermal lens technique Optical chopper Duty cycle variation...
Keywords: Photothermal phenomena Thermal lens technique Optical chopper Duty cycle variation
Published: 05.07.2022; Views: 96; Downloads: 0
.pdf Fulltext (1,30 MB)

7.
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