Stefan Lis

Stefan Lis
Adam Mickiewicz University | UAM · Faculty of Chemistry, Department of Rare Earths

Professor of Chemistry

About

319
Publications
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5,661
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Publications

Publications (319)
Article
The research is focused on hybrid, bifunctional composite materials, in terms of their application to innovative lightning systems. The main target was to obtain emissions in such materials for various colours other than red. In addition, the doping concentration was optimized and mechanical properties of the tested materials were improved. The mat...
Article
The work is focused on the preparation of biluminescent nanoparticles, in which Tb³⁺ and Eu³⁺-doped nanophosphors, based on an inorganic fluoride matrix were covered with luminescent metal nanoclusters of AuAg. Coating the surface of nanophosphors with nanoclusters allows prepared systems to emit light, which color (green/red or orange/red) depends...
Article
The concept of optical temperature sensing using band intensity ratio is considered as one of the most effective, self‐reference, non‐invasive, and rapid detection techniques for the local temperature in natural or engineered systems. In this work, for the first time a divalent lanthanide‐co‐doped dual‐center system, i.e., SrB4O7:Eu2+/Sm2+ phosphor...
Article
Full-text available
In this study, an optical thermometer based on regenerated cellulose fibers modified with YF3: 20% Yb3+, 2% Er3+ nanoparticles was developed. The presented sensor was fabricated by introducing YF3 nanoparticles into cellulose fibers during their formation by the so-called Lyocell process using N-methylmorpholine N-oxide as a direct solvent of cellu...
Article
A group of upconverting Ba2V2O7 barium pyrovanadate materials doped with Yb³⁺, Ho³⁺ was synthesized by hydrothermal method in a basic environment in order to promote the formation of [V2O7]⁴⁻ groups. The structural studies accompanied with the Rietveld analysis confirmed the excellent purity of the undoped matrix, while the increase in the phase co...
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Remote temperature and pressure monitoring provides new and exciting chances to explore the variation of luminescence properties of compounds under extreme conditions. Herein, series of Mn⁴⁺-activated, double perovskite Gd2ZnTiO6 phosphors were prepared to develop novel, bifunctional sensors of temperature and pressure. Upon 345 nm excitation, brig...
Article
To overcome the challenges of pressure monitoring with high sensitivity, we have designed a series of Ce³⁺-activated Ca2Gd8Si6O26 phosphors with outstanding pressure sensing properties. Excited with UV light, the resultant phosphors can emit a blue-violet luminescence, originating from optically active Ce³⁺ ions. The optimal doping content for Ce³⁺...
Article
Accurate, fast, and non-invasive methods for the determination of the local pressure magnitude are crucial for the investigation of the physical and chemical behavior of materials at the extreme conditions of high pressure. A promising method for remote operando pressure measurements is luminescence manometry. However, a limiting bottleneck for hig...
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Materials that generate pure, single-color emission are desirable in the development and manufacturing of modern optoelectronic devices. This work shows the possibility of generating pure, green up-conversion luminescence upon the excitation of Er3+-doped nanomaterials with a 785 nm NIR laser. The up-converting inorganic nanoluminophores YVO4: Er3+...
Article
Second harmonic generation (SHG) and upconversion luminescence (UCL), as second-order nonlinear optical (NLO) effects are crucial in modern optics and optoelectronics. Here, through the chemical engineering process we obtained a series of optically active BaTiO3: Er³⁺, Yb³⁺ perovskite materials, exhibiting temperature-dependent NLO responses. Upon...
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A new strategy for noninvasive temperature probing, applying the temperature-induced configuration crossover between the thermally-coupled ⁶ P 7/2 and 5d 1 levels of Eu ²⁺ is presented.
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Cellulose might be a promising material for surface-enhanced Raman scattering (SERS) substrates due to its wide availability, low cost, ease of fabrication, high flexibility and low optical activity. This work shows, for the first time development of the cellulose-based substrate, that owes its SERS activity to the presence of gold nanorods in its...
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Due to the ongoing need to create phosphors with the appropriate emission color for the production of light emitting diodes, we decided to synthesize a series of multicolour microphosphors with tunable visible emissions, depending on the composition of dopant ions. In this work, we investigated the structure, morphology, and luminescent properties...
Article
Optical thermometers are of great interest due to their non-contact, high-sensitivity and fast measurement characteristics. In this work, a series of dual-center Bi1.96-xMoO6: 0.02Er³⁺, 0.02Tm³⁺, xYb³⁺ (x=0.10-0.35) upconverting materials were prepared by a sol-gel synthesis method. Upon 975 nm excitation, the prepared materials exhibit bright colo...
Article
Noninvasive sensing of temperature and pressure offers new and exciting opportunities to investigate and monitor the variation of physicochemical and spectroscopic properties of materials under extreme conditions. In this work, Tm2+‐doped SrB4O7 phosphor material—a novel, contactless bifunctional, and multimodal optical sensor for pressure and temp...
Article
This work sheds the light on the pump power impact on the performance of luminescent thermometers, which is often underestimated by researchers. The up-converting, inorganic nanoluminophore YVO4:Yb3+, Er3+ (nanothermometer) was synthesized using the hydrothermal method and a subsequent calcination. The nanomaterial appears as a white powder compose...
Preprint
Full-text available
Single-phase CaSr 2 (PO 4 ) 2 :Dy ³⁺ ,Li ⁺ phosphors were prepared using the high-temperature solid-state method in the air. To characterize the luminescence properties of the synthesized phosphors, Powder X-ray diffraction patterns (XRD), scanning electron microscopy images (SEM), photoluminescence spectra, and concentration-dependent emission spe...
Article
A series of dual-mode nanomaterials based on Ba2LaV3O11:Yb³⁺, Er³⁺, Bi³⁺, with different bismuth content were synthesized using the hydrothermal method. Various analytical methods, such as x-ray diffraction (XRD) with additional detailed Rietveld analysis, transmission electron microscopy (TEM), inductively coupled plasma mass spectroscopy (ICP-MS)...
Article
Nonlinear optical spectroscopy may be a powerful tool for sensing of various intrinsic properties of materials and different state functions of the system. This is due to the strong dependence of nonlinear phenomena on numerous physicochemical factors. The feasibility of simultaneously employing the second harmonic generation (SHG) and upconversion...
Article
High-pressure X-ray diffraction studies on nanocrystals of the GdBO3 and YBO3 rare-earth orthoborates are herein reported up to 17.4(2) and 13.4(2) GPa respectively. The subsequent determination of the room-temperature pressure-volume equations of state is presented and discussed in the context of contemporary publications which contradict the find...
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Luminescent Ln 3+ ‐doped nanoparticles (NCs) functionalised with the desired organic ligand molecules for haemocompatibility studies were obtained by a one‐pot synthesis method. The ability to chelate various aromatic organic ligands such as: Isophthalic acid (IA) /Terephthalic acid (TA)/ Ibuprofen / Aspirin / 1, 2, 4, 5‐Benzenetetracarboxylic acid...
Article
Contactless optical nanothermometers of high thermal sensitivity are in great demand in various fields. In this work, we applied a facile sol-gel method to synthesize a series of Y2-xMoO6: xEr³⁺ upconverting nanoparticles (UCNPs), capable of acting as luminescence nanothermometers. Upon 980 nm laser light irradiation, with increasing Er³⁺ content,...
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Luminescence thermometers and manometers are among the most paramount emerging applications of phosphors nowadays, and remote reading is not the only attractive advantage they offer. Presently, truly encouraging examples offering both a wide operating range and appreciating thermal sensitivity are still limited. Double-mode sensors are especially a...
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Oligomeric-brush chains of helical lanthanide (Ln) complexes retain their structural and luminescent behavior after coating onto magnetic nanoparticles (MNPs) consisting of Fe3O4 covered with silicate. It is one of the type of bifunctional NPs exhibiting luminescence of Ln and superparamagnetism of Fe3O4. In comparison to a simple monolayer of comp...
Article
In our recent article on the luminescence and compressibility of monoclinic (phase α) and triclinic (β) GdBO3 submicron-sized crystals doped with Eu3+ the bulk modulus value Bo of phase α-GdBO3 should be 96(4) GPa, and for phase β-GdBO3 Bo =17.25(4) GPa.
Preprint
High-pressure X-ray diffraction studies on nanocrystals of the pseudo-vaterite-type borates GdBO$_3$ and YBO$_3$ are herein reported up to 17.4(2) and 13.4(2) GPa respectively. The subsequent determination of the room-temperature pressure-volume equations of state is presented and discussed in the context of contemporary publications which contradi...
Article
Up-converting nanothermometer YF3: 20% Yb³⁺, 0.5% Tm³⁺ was obtained via hydrothermal synthesis and a subsequent post-synthesis thermal treatment. The nanomaterial formed a stable colloid and showed (under 975 nm excitation) blue upconversion luminescence visible to the naked eye. The emission spectrum consisted of five thulium ion bands (450–870 nm...
Article
Nanophosphors based on NaM(WO4)2 (M = Gd, Y) doped with Yb³⁺/Ho³⁺ were synthesized in situ by a surfactant-assisted hydrothermal route. The average crystallite size of obtained nanophosphors was confirmed by transmission electron microscopy and scanning electron microscopy. Uniform nanocrystals of NaM(WO4)2 (M = Gd, Y) doped with Yb³⁺/Ho³⁺ formed w...
Article
The authors report a luminescence method based on energy transfer for the determination of permanganate ion in an aqueous medium. This is achieved using adenosine-capped CaF2:Eu³⁺ nanocrystals. Here, adenosine acts as a surfactant and a sensitizer for the Eu³⁺ ion in the CaF2 host matrix. The close proximity of the permanganate ion to the sensitizi...
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Full-text available
Lanthanide-based luminescent nanothermometers play a crucial role in optical temperature determination. However, due to the strong thermal quenching of the luminescence, as well as the deterioration of their sensitivity and resolution with temperature elevation, they can operate in a relative low temperature range, usually from cryogenic to ≈800 K....
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The growing interest in miniaturization of various devices and conducting experiments under extreme conditions of pressure and temperature causes the need for development of small, contactless, precise and accurate optical sensors, without any electrical connections. In this work, YF3:Yb³⁺-Er³⁺ upconverting micro-particles are used as a bi-function...
Article
The use of functional nanomaterials and their combination with organic polymers leads to the formation of advanced composites and hybrid inorganic-organic systems having unique properties. The use of such materials as anti-counterfeiting agents (invisible under ambient conditions) is crucial for modern security systems and for further identificatio...
Article
Novel precise thermometers are increasingly important due to the development of electronic and optoelectronic devices. Anti-Stokes luminescence of up-converting Sr3(PO4)2:Er³⁺,Yb³⁺ phosphor has been developed as a optical temperature sensor. The basic crystal structure, morphology, diffuse reflectance spectrum, chromaticity property, up-conversion...
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Full-text available
The concept of optical temperature sensing, based mainly on the band intensity ratio, line shift or luminescence lifetimes, is utilized for non-invasive and rapid detection of local temperature values in the inspected systems. For these purposes, lanthanide-doped nanoparticles (NPs) seem to be the most promising luminescence nanothermometers, becau...
Article
Luminescent lanthanide fluoride core‐shell (LaF3:Tb3+,Ce3+@SiO2‐NH2) nanoparticles, with acetyl salicylic acid (aspirin) coated on the surface were obtained. The synthesized products, combining the potential located in the silica shell with the luminescent activity of the core, were characterized in detail with the use of luminescence spectroscopy,...
Article
The monoclinic (α) and triclinic (β) GdBO3 submicron-sized crystals doped with Eu³⁺ ions were synthesized using different approaches (sol-gel Pechini and hydrothermal method). The luminescence properties of these two types of GdBO3 are different due to the different symmetry of the local coordination environment of Eu³⁺ ions, embedded in the invest...
Article
According to our knowledge, rare earth based upconverting ternary vanadates are synthesized by the hydrothermal method for the first time. This facile procedure offers an alternative approach to obtaining nanomaterials with the desired crystal structure, while omitting calcination step as to prevent from particle size growth and their agglomeration...
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Taking advantage of the excellent pressure-sensing properties of the Sm²⁺ ion in the SrB4O7 crystal, we demonstrate an enormous enhancement of about 60 times in the emission intensity of Sm²⁺ ions when Eu²⁺ ions are also incorporated into the crystalline structure. This enhancement is induced by the energy transfer from Eu²⁺ to Sm²⁺ ions. The spect...
Article
NaYbF4 luminophores doped with Ho³⁺ and increasing amount of Ce³⁺ were synthesized by the solvothermal method in a DAB-2 reactor. The structure and morphology of the obtained materials were determined by X-ray diffraction and a scanning electron microscope. It was confirmed that the phase structure and morphology can be changed by modifying the con...
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We report a facile and effective luminescence method for the determination of the WO42– ion in aqueous medium at initial pH = 6.3. This is achieved using 3,5-dihydroxybenzoic acid-capped CaF2:Tb³⁺ (5%) nanocrystals (NCs) as a luminescent probe. This is accomplished based on the energy transfer luminescence from the WO42– ion to the Tb³⁺ ion in smal...
Article
Counterfeiting of valuable documents, currency and branded products is a growing problem that has serious economic and security implications for governments and companies, as well as for ordinary people/customers. In order to prevent and detect falsification, continuous improvement of anticounterfeiting technology is required. This article presents...
Article
Currently the lowest optically determinable pressure values are around 102 bar, making the pressure below inaccessible for optical detection. This work shows for the first time how to overcome these limitations, and optically monitor the low pressure values in a vacuum region (from ≈10−5 to 10−2 bar), utilizing the light‐induced and pressure‐govern...
Article
The absorption characteristics of lanthanide-based functional materials is of key importance for many scientists and engineers, e.g. in luminescence studies, bioimaging, optical heating/cooling, Raman spectroscopy, as well as industrial applications, such as new light sources, optical sensors, labeling and tracing techniques, etc. Here we show the...
Article
Three complex strontium borate matrices, i.e. Sr3(BO3)2, SrB2O4 and SrB4O7 doped with Eu2+/Eu3+ ions, were prepared by the solid state reaction method in the air. X-ray and SEM analyses confirmed that all these samples are pure phase micro-sized materials. The luminescence properties of the Eu2+ and Eu3+ doped compounds were investigated in detail,...
Article
Luminescent YF3 nanoparticles doped with Pr3+ activator ion have been successfully synthesized via a facile hydrothermal approach for their application as a multi-range optical sensor of temperature. The product synthesized shows intense yellow luminescence at 457 nm laser excitation, and the emission spectra were recorded from 475 to 1650 nm, show...
Article
Preparation of LaF3:Gd³⁺ 30%, Ce³⁺ 10%, Eu³⁺ 1% NPs conjugated with CdTe quantum dots was performed by two methods. The first method includes mixing of two products, while the second method is based on the co-precipitation approach. The mixing of individual components did not lead to the formation of a new product. On the contrary, the product obta...
Article
Multifunctional core/shell type, luminescent-plasmonic material composed of lanthanide doped microspheres (≈50 μm) and gold nanoparticles (Au NPs; ≈10–20 nm) deposited onto their surface, were successfully prepared (Nd3+:YAS@Au). The material was synthesized to combine the luminescence properties of the Nd3+-doped microspheres, i.e. whispering reso...
Article
Gold nanorods (Au NRs), nanospheres and other nanoparticles display numerous superior physicochemical properties, such as resistance to oxidation and aggressive agents, strong enhancement of local electric field and high absorption coefficient in the visible and near-infrared (NIR) range. The absorption peaks of surface plasmon resonance (SPR) in A...
Article
Up-converting core@shell type β-NaYF4:Yb3+-Er3+@SiO2 nanorods have been obtained by a two-step synthesis process, which encompasses hydrothermal and microemulsion routes. The synthesized nanomaterial forms stable aqueous colloids and exhibits a bright dual-center emission (λex= 975 nm), i.e. up-conversion luminescence of Er3+ and down-shifting emis...
Article
Compression of up-converting (UC) YVO4 nanocrystals doped with Yb3+ and Er3+ ions leads to the luminescence color tuning, which can be used for the determination of pressure-induced zircon-to-scheelite phase transition. Spherical (≈20 nm), tetragonal YVO4: Yb3+-Er3+ UC nanoparticles (NPs) were synthesized by the hydrothermal method. The high-pressu...
Article
In this study, we present eight new complexes and self-assemblies of Tb(III), Eu(III), Zn(II) and Cu(II) ions with novel pyridine carboxamides, L1 [methyl 4-methyl-3-(pyridine-4-carbonylamino)benzoate] and L2 [methyl 2-methyl-3-(pyridine-4-carbonylamino)benzoate], as heterocyclic ligands. Two luminescent and spatially organized coordination compoun...
Preprint
div>The absorption peaks of surface plasmon resonance (SPR) in Au NRs are highly sensitive to their surrounding medium and to its refractive index ( RI ) changes. However, no applications of NRs for detecting phase transitions have been reported. Here we show that Au NRs effectively detect phase transitions of compressed compounds, liquid and solid...
Article
A novel, contactless optical sensor of pressure based on the luminescence red-shift and band width (full width at half maximum - FWHM) of the Ce3+-doped fluorapatite - Y6Ba4(SiO4)6F2 powder, has been successfully synthesized via a facile solid-state method. The obtained material exhibits a bright blue emission under UV light excitation. It was char...
Article
The article describes the properties of LuF3 and NaLuF4 fluorides doped with Yb³⁺ and Er³⁺ or Tm³⁺ ions, their comparison and application in latent fingermarks imaging. The single-phase materials were successfully synthesized by the hydrothermal method. They exhibited up-conversion (UC) phenomenon under excitation by the near-infrared (NIR) radiati...
Article
This article presents synthesis and properties of the fibers modified with luminescent, inorganic nanoparticles doped with lanthanide(III) ions, i.e. LaF3:Ce3+, Gd3+, Eu3+; CeF3:Tb3+ and CePO4:Tb3+. The fibers with luminescent properties were prepared via so called Lyocell process. This method involves dissolving cellulose in aqueous solution of N-...
Article
Microcrystals of the inorganic red emitting phosphors EuxCa1-1.5xMoyW1-yO4 (x = 0.00667, 0.03333, 0.06667; y = 0, 0.1, … 0.9, 1) were synthesized by a traditional solid-state method. Studied materials were characterized by X-ray diffraction, infrared spectroscopy and luminescence spectroscopy (luminescence spectra and lifetime measurements). The mo...
Article
In this report the thirteen new compounds including five new heterocyclic ligands and eight complexes with Cu(II), Zn(II) and Ni(II) ions are presented. The investigation of subsequent amide derivatives of picolinic and isonicotinic acid was performed to compare the coordination affinity for this carboxamide series. Moreover the magnetic properties...
Article
Full-text available
Novel luminescent–magnetic cellulose microfibers were prepared by a dry–wet spinning method with the use of N-methylmorpholine-N-oxide. The synthesized luminescent–magnetic core/shell type nanostructures, based on the lanthanide-doped fluorides and magnetite nanoparticles (NPs)—Fe3O4/SiO2/NH2/PAA/LnF3, were used as nanomodifiers of the fibers. Than...
Article
A new, non-contact optical sensor of pressure based on the SrB2O4:Sm2+ nanoparticles has been successfully synthesized via a simple and low-cost Pechini method. The obtained nanomaterial was thoroughly characterized using powder X-ray diffraction, transmission electron microscopy, and Raman and luminescence spectroscopies, including high-pressure a...
Article
Several complex strontium borate matrices (Sr3(B2O6), Sr2(B2O5), SrB2O4, SrB4O7, SrB6O10 and SrB8O11) doped with Sm2+/3+ ions were prepared using a modified Pechini method, with increasing Sr2+/boric acid ratio and a two-step annealing process. The Sm3+ ions were transformed into Sm2+ ones without additional reducing agents during the syntheses per...