arXiv subjects

L. Marciniak

Publications and source records attributed to L. Marciniak.

11 recordsLinked to original sources

arXiv2026

Unlocking the Potential of Ni2+ and Ni2+-Cr3+ Synergy for Bifunctional Pressure and Temperature Optical Sensing

Reliable simultaneous optical sensing of pressure and temperature under extreme and dynamically fluctuating conditions remains a major challenge due to intrinsic cross-sensitivity between these two thermodynamic parameters. Multimodal systems enabling simultaneous yet fully decoupled monitoring of both parameters are therefore highly sought after. Here, we demonstrate that the synergistic interplay between Cr3+ and Ni2+ luminescence provides a platform for bifunctional temperature-pressure sensing with independent readout channels. Two complementary detection strategies were systematically investigated: ratiometric approach based on luminescence intensity ratio and kinetic approaches exploiting emission decay dynamics. Among the kinetic strategies, a time-gated dual-ion lifetime concept - introduced here for the first time for luminescence manometry - enables pressure readout with record-high relative sensitivity reaching 148.33% GPa-1 while exhibiting complete immunity to temperature fluctuations. Conversely, temperature sensing is achieved via time-gated single-ion Ni2+ luminescence, ensuring high thermometric performance with negligible pressure-induced interference. Importantly, this work study, for the first time, the potential of Ni2+ ions for application in near-infrared luminescence manometry. The unique combination of ultrahigh sensitivity, multimodal readout capability, and possibility of near-infrared operation positions the Ni2+-Cr3+ luminescence synergy as a benchmark platform for next-generation bifunctional optical sensors, enabling reliable operation in complex, dynamically evolving, and optically demanding environments.

cond-mat.mtrl-sci↗

arXiv2026

Role of the Nephelauxetic Effect in Engineering Mn4+ Luminescence Kinetics for Lifetime-Based Thermometry

Although the considerable potential of luminescence thermometry based on emission kinetics has been widely demonstrated, reliable tools for the intentional prediction of thermometric performance remain limited. To address this challenge, the present work introduces an approach that enables a theoretical description of the 2E state lifetime of Mn4+ ions, as well as the absolute and relative sensitivities, in terms of the nephelauxetic effect within the group of double perovskites: Sr2InNbO6, Sr2InTaO6, Ba2InTaO6, and Ba2InNbO6. Our results clearly show that, contrary to common assumptions, the Dq/B ratio is not the primary factor governing either the spectroscopic behavior of Mn4+ ions or the thermometric performance of Mn4+-doped phosphors. Instead, the nephelauxetic beta1 parameter plays the dominant role. The empirical analysis carried out in this study led to the development of a predictive model that enables estimation of SAMAX and SRMAX values based exclusively on beta1. This methodology represents a significant step toward the rational design of lifetime-based luminescence thermometers with predefined thermometric characteristics tailored to the requirements of specific applications.

cond-mat.mtrl-sci↗

arXiv2026

Second-Coordination-Sphere Cation Substitution as a Tool for Controlling Phase Transitions and Performance of the Luminescence Thermometry

Despite the exceptionally high relative sensitivities achieved by luminescent thermometers based on first-order structural phase transitions, their principal limitation lies in the inherently narrow thermal operating range associated with the transition temperature. In this work, we demonstrate that partial substitution of Li+ by Na+ ions in the second coordination sphere of Eu3+ ions in LiYO2 enables a substantial shift of the phase transition temperature, thereby allowing controlled optimization of the thermometric performance. This approach represents a significantly more cost-effective and efficient strategy for tuning the phase transition temperature compared with the previously proposed substitution of Y3+ by other lanthanide ions. Importantly, we show that lowering the transition temperature through Na+ incorporation simultaneously introduces static compositional disorder and local lattice strain. As a consequence, the enthalpy difference between the competing structural phases decreases, and the cooperativity of the lattice distortion is reduced, indicating a gradual weakening of the first-order character of the phase transition. Our results demonstrate that such structural modifications, while effective in shifting the transition temperature, inevitably lead to a reduction in the relative sensitivity of phase-transition-based luminescent thermometers.

cond-mat.mtrl-sci↗

arXiv2026

Visual Luminescence Thermometry Enabled by Phase-Transition-Activated Cross Relaxation of Tb3+ Ions

The development of visual luminescent thermometers capable of exhibiting pronounced color changes in response to temperature variations requires the rational design of phosphors with high spectrally selective thermal sensitivity. In this work, we present a strategy based on phase-transition-induced activation of cross-relaxation processes in LiYO2:Tb3+. The monoclinic-to-tetragonal structural phase transition modifies the point symmetry of Tb3+ ions in the host lattice, enhances the Stark effect, and enables energetic resonance required for efficient cross relaxation. Consequently, emission originating from the 5D3 excited state is rapidly quenched relative to that from the 5D4 level above approximately 300 K, resulting in a distinct temperature-dependent color change of the emitted light from blue to green. This mechanism yields exceptionally high chromaticity-coordinate-based sensitivities, reaching SRx,max = 0.40% K-1 and SRy,max=0.72% K-1 at 410 K. Furthermore, phase-transition-driven modifications of the Tb3+ emission spectral profile enable the realization of a multimode luminescent thermometer with a maximum relative sensitivity of SRmax=13% K-1. The practical applicability of this system is demonstrated through an ON-OFF luminescent thermal switch and fully filter-free, dynamic two-dimensional thermal imaging using the blue and green channels of a standard digital camera, enabling intuitive visualization, remote readout, and temperature mapping under dynamic conditions.

cond-mat.mtrl-sci↗

arXiv2025

Unusual Thermally Induced Blueshift and Emission Amplification of Mn2+ ions Enable Filter-Free Luminescent Thermal Imaging

The shift from point-based thermal sensing to filter-free thermal imaging requires luminescent thermometers that exhibit pronounced and thermally driven spectral changes within spectral regions matching the sensitivity profiles of the R, G, and B channels of a digital camera. In this work, we introduce such a system, enabled by the synergistic interplay between (i) thermal redistribution among the vibronic components of the 4T1 excited state of Mn2+ ions and (ii) thermally assisted population of this state via optical trap sites. These combined processes result in a simultaneous thermal enhancement and blueshift of the Mn2+ emission band associated with the 4T1 -> 6A1 electronic transition. Consequently, the emission intensity recorded in the G channel increases with temperature, while the luminescence signals detected in the B channel exhibit a corresponding decrease. As demonstrated, Ca19Zn2(PO4)14:Mn2+, Ce3+ supports not only sensitive filter-free thermal imaging, but also two additional ratiometric readout schemes: one based on the intensity ratio of Ce3+ and Mn2+ emissions, and another based on two distinct spectral regions of the Mn2+ emission band, yielding maximum relative sensitivities of 0.42% K^-1 and 2.7% K^-1, respectively. This approach introduces a unique thermometric strategy that enables simple, robust, and cost-effective two-dimensional thermal imaging without the need for optical filters or specialized instrumentation.

cond-mat.mtrl-sci↗

arXiv2025

Dual-Mode Luminescent Thermometry in LiYO2:Nd3+,Yb3+ Enabled by Structural Phase Transition and Phonon-Assisted Energy Transfer

In this work, a dual-mode luminescent thermometer operating via both ratiometric and lifetime-based readout strategies was developed, enabled by the coexistence of two thermally driven effects: a structural phase transition in LiYO2 and a phonon-assisted energy transfer from Yb3+ to Nd3+. As demonstrated, changes in the shape of the emission band of Yb3+ ions corresponding to the 2F5/2 -> 2F7/2 electronic transition, induced by the phase transition, enabled the design of a ratiometric thermometer with a maximum relative sensitivity (SR) of 3.1% K^-1 for LiYO2 doped with 10% Yb3+ and 1% Nd3+ at 290 K. In contrast, the temperature-dependent Yb3+ -> Nd3+ energy transfer facilitated the development of a lifetime-based thermometer with a maximum SR of 1.5% K^-1 for 20% Nd3+ at 378 K. In both approaches, tuning the Nd3+ concentration allowed modulation of both the sensitivity and the temperature at which the maximum SR occurred. This was achieved by shifting the phase transition temperature and increasing the probability of interionic energy transfer, respectively. Notably, the temperature ranges corresponding to the maximum SR for the ratiometric and lifetime modes were distinct, effectively broadening the thermal operating window of the sensor. Additionally, it was shown that LiYO2 doped with Nd3+ and Yb3+ can also be used as a temperature sensor through the ratio of luminescence intensities recorded at two different time gates. Furthermore, the results confirmed that the phonon-assisted energy transfer process plays the dominant role in shaping the luminescence kinetics, surpassing the influence of the structural phase transition. Overall, this study identifies LiYO2:Nd3+,Yb3+ as a promising candidate for multimodal luminescent temperature sensing applications.

cond-mat.mtrl-sci↗

arXiv2025

Phase Transition Under Control: Toward Application-Oriented Luminescence Thermometry and Thermally Activated Emission

Phase-transition-based luminescent thermometers are characterized by two inherent limitations: a narrow thermal operating range and the presence of a hysteresis loop in the thermometric parameter. In this work, we demonstrate that controlling the particle size of LaGaO3:Eu3+ phosphors enables significant enhancement of thermometric performance. Specifically, a reduction in grain size dispersion leads to an increase in relative thermal sensitivity and significantly narrows the hysteresis loop. As a result of this approach, the relative sensitivity was increased to 18.2% K-1 for LaGaO3:Eu3+ synthesized via the solid-state method, compared to 3.0% K-1 for the counterpart prepared using the Pechini method. Furthermore, we show that the intentional incorporation of Al3+ and Sc3+ co-dopant ions allows for continuous tuning of the structural phase transition temperature from 165 K for 15% Al3+ to 491 K for 2% Sc3+, without significantly affecting the low-temperature spectroscopic properties of Eu3+ ions. This ability to shift the phase transition temperature in LaGaO3 offers a practical route to modulate the thermal response range of the luminescent thermometer, enabling its adaptation to specific application requirements. The empirical relationship established in this study between the phase transition temperature and the ionic radius mismatch parameter provides a predictive tool for the rational design of phase-transition-based phosphors with tailored thermometric performance. The ability to systematically tune the phase transition temperature via ionic radius mismatch, together with enhanced thermometric performance resulting from reduced grain size dispersion, establishes a coherent strategy for the rational design of high-sensitivity, low-hysteresis thermal sensors.

cond-mat.mtrl-sci↗

arXiv2025

Breaking Sensitivity Barriers in Luminescence Thermometry: Synergy Between Structural Phase Transition and Luminescence Thermal Quenching

One of the key parameters determining the performance of a luminescent thermometer is its relative sensitivity. In ratiometric luminescence thermometry, high relative sensitivity to temperature variations is typically achieved when the two monitored emission bands exhibit opposite thermal monotonicity. However, realizing a thermal enhancement in the luminescence intensity of one of the emission bands remains a significant challenge. In this study, we present a novel approach that leverages the synergistic effect of two phenomena: (1) the high thermal sensitivity of Mn4+ ion luminescence, and (2) a thermally induced structural phase transition in LaGaO3, which facilitates the enhancement of the luminescence signal from Tb3+ ions in the high-temperature phase of the host material. This dual effect not only led to an increased maximum relative sensitivity but also extended the temperature range over which the sensitivity exceeded 1% K-1. The highest recorded sensitivity was 4.5 K-1 at 400 K. Additionally, to the best of our knowledge, the luminescence of Mn4+ ions in the high-temperature phase of LaGaO3:Mn4+ was observed and reported here for the first time. The thermally induced modifications in the emission profile of LaGaO3:Mn4+,Tb3+ enabled the development of a quadruple ratiometric luminescence thermometer, with complementary operating ranges, offering enhanced versatility and accuracy across a broad temperature span.

cond-mat.mtrl-sci↗

arXiv2025

Luminescence thermometry based on time gates: highly sensitive approach for real time sensing and imaging

Undoubtedly, one of the most significant advantages of luminescence thermometry is its ability to be used not only for spot temperature measurements but also for imaging temperature changes. Among the commonly proposed approaches, luminescence thermometry based on luminescence kinetics holds particular promise. However, most thermometric studies rely on the analysis of luminescence decay profiles, a method that significantly hinders, if not entirely precludes, real-time thermal imaging. In this paper, we propose an alternative approach based on the luminescence intensity ratio integrated over two temporal gates. Tests conducted on two representative phosphors, Ba2LaNbO6:1%Mn4+ and Ca2LaNbO6:1%Mn4+, demonstrate that the proposed method not only enables thermal imaging but also achieves substantially higher relative sensitivity, reaching SR=17.1 % K-1 for Ba2LaNbO6:1%Mn4+ and SR=9.4 % K-1 for Ca2LaNbO6:1%Mn4+, compared to the conventional lifetime-based approach (SR=4.2 % K-1 for Ba2LaNbO6:1%Mn4+ and SR=1.2 % K-1 for Ca2LaNbO6:1%Mn4+). Furthermore, careful selection of gate lengths allows optimization of the thermometric performance of the proposed luminescent thermometers. This approach enables expansion of the thermal operating range at the cost of relative sensitivity, providing versatility to adapt the thermometer for specific applications.

physics.app-ph↗

arXiv2025

Expanding the Horizons of Phase Transition-Based Luminescence Thermometry

The limited operational range of phase transition-based luminescence thermometers necessitates the exploration of new host materials exhibiting first-order structural phase transitions to broaden the applicability of this approach. Addressing this need, the present study investigates the spectroscopic properties of as a function of temperature. A thermally induced structural transition from the low-temperature orthorhombic phase to the high-temperature trigonal phase, occurring at approximately 430 K, significantly alters the spectroscopic properties of Eu3 ions. Specifically, a reduction in the number of Stark lines due to changes in the point symmetry of Eu3 ions enables the development of a ratiometric luminescence thermometer with sensitivity as high as K. Furthermore, it was demonstrated that increasing the concentration of Eu3 ions shifts the phase transition temperature, allowing for modulation of the thermometric performance of this luminescence thermometer. The findings presented here not only expand the repertoire of phase transition-based luminescence thermometers but also illustrate how the luminescence properties of Eu3 ions can be employed to accurately monitor structural changes in the host material.

cond-mat.mtrl-sci↗

arXiv2024

NIR-to-NIR lifetime based thermometry with the thermally elongated luminescence kinetics driven by structural phase transition in LiYO2:Yb3+

Among the various techniques used in luminescence thermometry, luminescence kinetics is considered the least sensitive to perturbations related to the optical properties of the medium containing the phosphor. For this reason, temperature sensing and imaging using lifetime-based luminescence thermometers is of high interest for wide range of specific applications. However, for most such thermometers, an increase in temperature leads to a shortening in lifetime, which can hinder the specificity and accuracy of the readout. In this work, we present an approach that utilizes a thermally induced increase in the symmetry of the host material associated with a structural phase transition in LiYO2:Yb3+. Consequently, the lifetime of the excited level 2F5/2 of the Yb3+ ion is thermally prolonged, achieving a relative sensitivity of 0.5%/K. The phase transition temperature can be controlled by adjusting the dopant concentration. Additionally, thermal changes in the emission spectrum enable the use of LiYO2:Yb3+ for ratiometric temperature readout with a relative sensitivity of 5.3%/K at 280K for LiYO2:5%Yb3+.

cond-mat.mtrl-sci↗