Showing 1–4 of 4 results for author: Javaid, A

Structural Phase Transition and Cooperative Luminescence in K3Yb(PO4)2:Eu3+ for Multimodal Down-shifting and Up-converting Luminescence Thermometry

Authors: Anam Javaid, Maja Szymczak, Damian Szymanski, Lukasz Marciniak

Abstract: To develop a more universal luminescent thermometer that provides both high relative sensitivity and the ability to measure temperature across different spectral ranges and excitation wavelengths, the K3Yb(PO4)2:Eu3+ system was proposed in this work. It was demonstrated that this material undergoes a structural phase transition from the monoclinic to the hexagonal phase above 450 K. This transitio… ▽ More To develop a more universal luminescent thermometer that provides both high relative sensitivity and the ability to measure temperature across different spectral ranges and excitation wavelengths, the K3Yb(PO4)2:Eu3+ system was proposed in this work. It was demonstrated that this material undergoes a structural phase transition from the monoclinic to the hexagonal phase above 450 K. This transition enabled the construction of a ratiometric, phase-transition-based thermometer utilizing the luminescence intensity ratio of Stark lines of Eu3+ and Yb3+ ions, which exhibit SRmax values of 4.2% K^-1 and 1.15% K^-1, respectively. Moreover, increasing the Eu3+ ion concentration was shown to raise the phase transition temperature, thereby shifting the thermal operating range of both luminescent thermometers. Under 980 nm excitation, K3Yb(PO4)2:Eu3+ exhibits both cooperative luminescence from Yb3+ pairs and up-conversion emission from Eu3+ ions. Increasing the Eu3+ concentration enhances the Eu3+ luminescence intensity relative to the cooperative luminescence of Yb3+ pairs, resulting in a change in the emitted light color. The difference in the thermal quenching behavior of these two signals further enabled the development of a ratiometric thermometer with SRmax = 0.58% K^-1. These findings identify K3Yb(PO4)3:Eu3+ as a promising candidate for multimodal temperature sensing. △ Less

Submitted 10 December, 2025; originally announced December 2025.

From the up-converting multimodal luminescent thermometer to ratiometric visual power density meter based on Er3+,Yb3+ emission

Authors: Anam Javaid, Maja Szymczak, Lukasz Marciniak

Abstract: This study demonstrates that thermally induced variations in the spectroscopic properties of Na3Sc2(PO4)3:Er3+, Yb3+ can be effectively harnessed for multimodal remote temperature sensing. As shown, Na3Sc2(PO4)3:Er3+, Yb3+ supports multiple ratiometric sensing modes based on the intensity ratios of (i) 2H11/2 -> 4I15/2 and 4S3/2 -> 4I15/2; (ii) 2H9/2 -> 4I13/2 and 4S3/2 -> 4I15/2; and (iii) green-… ▽ More This study demonstrates that thermally induced variations in the spectroscopic properties of Na3Sc2(PO4)3:Er3+, Yb3+ can be effectively harnessed for multimodal remote temperature sensing. As shown, Na3Sc2(PO4)3:Er3+, Yb3+ supports multiple ratiometric sensing modes based on the intensity ratios of (i) 2H11/2 -> 4I15/2 and 4S3/2 -> 4I15/2; (ii) 2H9/2 -> 4I13/2 and 4S3/2 -> 4I15/2; and (iii) green-to-red emission intensity ratio, achieving maximum relative sensitivities of 2.8% K-1, 3% K-1, and 1.8% K-1, respectively. The synergy between thermal changes observed in the green-to-red emission intensity ratio of Er3+ ions, combined with the efficient optical heating of Na3Sc2(PO4)3:Er3+, Yb3+ at elevated Yb3+ concentrations enables the development of a visual optical power density sensor, exhibiting relative sensitivities of SRx = 1.0% W-1 cm2 and SRy = 0.9% W-1 cm2 at 15 W cm-2 when quantified using CIE 1931 chromaticity coordinates. To the best of our knowledge, this is the first report of a visual luminescent optical power density sensor. Furthermore, it was demonstrated that Na3Sc2(PO4)3:Er3+, Yb3+ can be successfully applied for two-dimensional imaging of optical power density, thereby enabling spatial visualization of power distribution within an illuminated field. △ Less

Submitted 17 July, 2025; originally announced July 2025.

Luminescent Platform for Thermal Sensing and Imaging Based on Structural Phase-Transition

Authors: Anam Javaid, Maja Szymczak, Malgorzata Kubicka, Vasyl Kinzhybalo, Marek Drozd, Damian Szymanski, Lukasz Marciniak

Abstract: The remarkable sensitivity of the luminescent properties of Eu3+ ions to structural changes in host materials has been well-explored for years. However, the application of this feature of Eu3+ in materials exhibiting thermally induced structural phase transitions for the development of luminescent thermometers has only recently been proposed. The narrow operating range of such thermometers necessi… ▽ More The remarkable sensitivity of the luminescent properties of Eu3+ ions to structural changes in host materials has been well-explored for years. However, the application of this feature of Eu3+ in materials exhibiting thermally induced structural phase transitions for the development of luminescent thermometers has only recently been proposed. The narrow operating range of such thermometers necessitates the exploration of new host materials. In response to this demand, this study carefully analyzes the spectroscopic properties of X as a function of temperature and dopant ion concentration. As demonstrated, X undergoes a phase transition from a low-temperature monoclinic phase to a high-temperature trigonal structure, resulting in significant changes in both the emission spectrum shape of Eu ions and the depopulation kinetics of the 5D0 level. Consequently, X can be utilized as both a ratiometric and a lifetime-based luminescence thermometer, achieving maximal relative sensitivities of 3.4 and 1.0 or the respective approaches. Additionally, this work highlights how increasing the concentration of Eu3+ ions enables the tuning of the thermal operating range to achieve optimal thermometric performance. Moreover, an implementation of ratiometric approach of temperature sensing and imaging with X using digital camera without filters was demonstrated. This is the first report that demonstrates thermal imaging using Eu3+-solely doped phosphor. This finding underscores the potential of X as a versatile host material for advanced luminescent thermometry applications. △ Less

Submitted 9 May, 2025; originally announced May 2025.

NIR-to-NIR ratiometric and lifetime based luminescence thermometer on a structural phase transition in Na3Sc2(PO4)3:Yb3+

Authors: Anam Javaid, Maja Szymczak, Malgorzata Kubicka, Justyna Zeler, Vasyl Kinzhybalo, Marek Drozd, Damian Szymanski, Lukasz Marciniak

Abstract: The ratiometric approach is the most commonly employed readout technique in luminescence thermometry. To address the trade-off between the risk of measurement disturbance in thermometers with high spectral separation of emission bands (due to dispersion in the surrounding medium) and the low sensitivity observed in ratiometric thermometers based on Stark level thermalization, we propose a thermome… ▽ More The ratiometric approach is the most commonly employed readout technique in luminescence thermometry. To address the trade-off between the risk of measurement disturbance in thermometers with high spectral separation of emission bands (due to dispersion in the surrounding medium) and the low sensitivity observed in ratiometric thermometers based on Stark level thermalization, we propose a thermometer based on the structural phase transition in . The use of Yb3+ ions as dopants and the changes in Stark level energies associated with the thermally induced monoclinic-to-trigonal phase transition enable the development of a thermometer with high relative sensitivity, achieving at 340K for N. Additionally, as demonstrated, the structural transition alters the probability of radiative depopulation of the 2F5/2 state of Yb3+, allowing the development of a lifetime-based luminescence thermometer. Furthermore, the phase transition temperature and consequently the thermometric performance of can be modulated by varying the Yb3+ ion concentration, offering additional tunability for specific applications. △ Less

Submitted 2 April, 2025; originally announced April 2025.