Dual-mode Luminescence Research Articles

Enhancement of persistent luminescence and mechanoluminescence in Pr3+ doped CaAl2Si2O8: Mn for multifunctional applications at wide temperature range

The orange-red phosphor, which combines persistent luminescence and mechanoluminescence, holds significant importance in advanced bioimaging and optical anti-counterfeiting. However, there are relatively few reports on this type of material currently. In this study, doping CaAl2Si2O8: Mn2+ phosphor with Pr3+ ions significantly increases the material's defect density. Under X-ray/UV excitation, the sample displays exceptional orange-red persistent luminescence and superior mechanoluminescence. More importantly, the samples exhibit the above properties in all temperature regions (including low temperature, room temperature (RT) and high temperature). Additionally, the material demonstrates excellent tissue penetration capabilities and dual-mode luminescence (persistent luminescence and mechanoluminescence), highlighting its potential for bioimaging and optical anti-counterfeiting applications.

Luminescent properties of Y2LaCaGa3ZrO12: Bi3+, Al3+ cyan phosphors for application in white light emitting diodes

High-quality white light can be obtained from a mixture of blue, green, and red phosphors excited by ultraviolet chips. However, this approach suffers from the presence of a cyan gap in the emission spectra, which hinders further improvement in the color rendering index (CRI). The obvious solution to this problem should be the development of efficient ultraviolet-excited cyan phosphors to fill this gap. Therefore, a series of Y2LaCaGa3ZrO12: xBi3+ (x = 0–0.1) cyan phosphors were synthesized via high-temperature solid-state reaction method, and their properties were systematically characterized. The Bi3+ ion in Y2LaCaGa3ZrO12 exhibits dual-mode luminescence with emission bands peaking at 356 nm and 483 nm, originating from the 3P1→1S0 transitions of Bi3+ at different sites. The ultraviolet emission is attributed to Bi3+ occupying 8 coordination sites, while the cyan emission arises from Bi3+ in 6 coordination sites. It is noteworthy that the emission intensity and thermal stability of the phosphors can be further improved by partially substituting Ga3+ with Al3+. By incorporating Y2LaCaGa3ZrO12: 0.02Bi3+ or Y2LaCaGa2.7Al0.3ZrO12: 0.02Bi3+ with commercial phosphors and depositing them onto a 365 nm ultraviolet chip, the prototype white light emitting diodes (w-LEDs) exhibits white light with high CRI of 89.6 and 90.4, respectively. These results validate the potential of Bi3+ activated Y2LaCaGa3-yAlyZrO12 (y = 0–1) cyan phosphor as a promising candidate material for application in UV-excited w-LEDs.

Biothiols-activated near-infrared frequency up-conversion luminescence probe for early evaluation of drug-induced hepatotoxicity

A novel biothiols-sensitive near-infrared (NIR) fluorescent probe RhDN based on a rhodamine skeleton was developed for early detection of drug-induced hepatotoxicity in living mice. RhDN can be used not only as a conventional large stokes shift fluorescent (FL) probe, but also as a kind of anti-Stokes frequency upconversion luminescence (FUCL) molecular probe, which represents a long wavelength excitation (808 nm) to short wavelength emission (760 nm), and response to Cys/Hcy/GSH with high sensitivity. Compared with traditional FL methods, the FUCL method exhibited a lower detection limit of Cys, Hcy, and GSH in 75.1 nM, 101.8 nM, and 84.9 nM, respectively. We exemplify RhDN for tracking endogenously biothiols distribution in living cells and further realize real-time in vivo bioimaging of biothiols activity in mice with dual-mode luminescence system. Moreover, RhDN has been successfully applied to visualize the detection of drug-induced hepatotoxicity in living mice. Overall, this report presents a unique approach to the development of large stokes shift NIR FUCL molecular probes for in vitro and in vivo biothiols biosensing.

Upconversion Emission and Dual-Mode Sensing Characteristics of NaYF4:Yb3+/Er3+ Microcrystals at High and Ultralow Temperatures.

In this study, we investigate micrometer-sized NaYF4 crystals double-doped with Yb3+/Er3+ lanthanide ions, designed for temperature-sensing applications. In contrast to previous studies, which focused predominantly on the high-temperature regime, our investigation spans a comprehensive range of both high and ultralow temperatures. We explore the relationship between temperature and the upconversion luminescence (UCL) spectra in both frequency and time domains. Our findings highlight the strong dependence of these spectral characteristics of lanthanide-doped NaYF4 crystals on temperature. Furthermore, we introduce a dual-mode luminescence temperature measurement technique, leveraging the upconversion emission intensity ratio for both green and red emissions. This study also examines the correlation between temperature sensing, energy level disparities, and thermal coupling in Er3+ ions across various temperature scales. Our research contributes to advancing the understanding and application of lanthanide-doped materials, setting a foundation for future innovations in temperature sensing across diverse fields.

One-step preparation and dual mode luminescence anti-counterfeiting application of LiYF4: Yb3+, Ho3+, Ce3+@ carbon quantum dot composite materials

In the field of fluorescent anti-counterfeiting, materials with single luminous mode are easy to be forged, which cannot meet the current anti-counterfeiting requirements. Currently reported bimodal light-emitting materials usually require multi-step and tedious synthesis steps. In this paper, LiYF4: Yb3+, Ho3+, Ce3+ upconversion micron particles (UCMPs)/carbon quantum dots (CDs) composite materials were prepared by one-step hydrothermal method, which greatly simplified the composite process of CDs and UCMPs. The upconversion wavelength (from green light to red light excited by 980 nm) can be achieved by changing the doping concentration of Ce3+ ions. Through the combination of CDs and UCMPs, an obvious dual mode luminescence phenomenon was achieved. Finally, screen printing was used to produce a clover pattern, which realized multi-color luminescence under 365 nm and 980 nm excitations respectively. The new fluorescence anti-counterfeiting composites, which uses simple and environmentally friendly one-step synthesis process, is expected to promote the development of fluorescence anti-counterfeiting field.

Optical temperature sensing of Yb,Er:GSAG single crystal in both upconversion and downconversion dual-mode luminescence

Fluorescence intensity ratio thermometry represents a novel non-contact approach for rapid and precise temperature measurements. In this study, a Yb,Er co-doped Gd3Sc2Al3O12 single crystal (Yb,Er:GSAG) was investigated, exploiting the dual-mode luminescence of upconversion and downconversion for optical temperature sensing applications. The crystal exhibited distinct luminescence behaviors when subjected to 266 nm, 355 nm, and 980 nm laser excitations, manifesting a dark blue appearance under 266 nm ultraviolet (UV) excitation and a green hue under 355 nm and 980 nm excitations. Specifically, under 355 nm excitation, the crystal demonstrated a predominantly pure green upconversion, with a green-to-red ratio of 38. For the first time, we propose an investigation into the temperature sensing behavior under dual-mode luminescence in the same crystal, utilizing the fluorescence intensity ratio of the 2H11/2 and 4S3/2 thermally coupled energy levels of Er3+. The obtained maximum relative sensitivities (SR) for the two fitted luminescence modes were found to be 101.80×10−4 K−1 at 300 K (980 nm excitation) and 126.39×10−4 K−1 at 300 K (355 nm excitation), respectively. The impressive SR values substantiate Yb,Er:GSAG crystal as highly promising candidates for optical temperature sensing applications.

Dual-mode luminescence light intensity modulation characteristics and optical radiation dependence of stannate photochromic ceramics

Alkaline earth stannate is characterized by good physicochemical stability. It has been applied in the field of optical information storage by coupling photoluminescence intensity modulation and photochromic performance, which has attracted the attention of researchers. The development of alkaline earth stannate ceramics with high light intensity modulation properties and non-destructive reading of optical information is of great research value. In this study, Er3+-doped Ca2SnO4 photochromic ceramics were prepared by high-temperature solid-phase reaction method. Alternating UV light irradiation and thermal stimulation, the ceramics achieve a reversible transition between light and dark gray. Er3+ doping gives the ceramics dual-mode luminescence light intensity modulation performance. When the doping amount of Er3+ is 0.01 mol, there is a maximum down-conversion luminous intensity modulation ratio of 93%, which is higher than most of the same type of photochromic materials. The photochromic behavior is explained using the capture-release model of traps for carriers, and the dual-mode luminescence light-intensity modulation behavior is analyzed through the energy transfer mechanism. The optical radiation response properties were investigated and the optimum light response wavelength is found to be 290 nm, which is related to the optical band gap Eg. And the selection of the optimal light response wavelength can effectively improve the performance of photochromic and light intensity modulation. This study provides a promising strategy for performance enhancement of photochromic materials.

The Combination of Upconversion Nanoparticles and Perovskite Quantum Dots with Temperature-Dependent Emission Colors for Dual-Mode Anti-Counterfeiting Applications.

Novel and high-security anti-counterfeiting technology has always been the focus of attention and research. This work proposes a nanocomposite combination of upconversion nanoparticles (UCNPs) and perovskite quantum dots (PeQDs) to achieve color-adjustable dual-mode luminescence anti-counterfeiting. Firstly, a series of NaGdF4: Yb/Tm UCNPs with different sizes were synthesized, and their thermal-enhanced upconversion luminescence performances were investigated. The upconversion luminescence (UCL) intensity of the samples increases with rising temperature, and the UCL thermal enhancement factor rises as the particle size decreases. This intriguing thermal enhancement phenomenon can be attributed to the mitigation of surface luminescence quenching. Furthermore, CsPbBr3 PeQDs were well adhered to the surfaces and surroundings of the UCNPs. Leveraging energy transfer and the contrasting temperature responses of UCNPs and PeQDs, this nanocomposite was utilized as a dual-mode thermochromic anti-counterfeiting system. As the temperature increases, the color of the composite changes from green to pink under 980 nm excitation, while it displays green to non-luminescence under 365 nm excitation. This new anti-counterfeiting material, with its high security and convenience, has great potential in anti-counterfeiting applications.

Emission color tuning and dual-mode luminescence thermometry design in Dy3+/Eu3+ co-doped SrMoO4 phosphors

The challenge of building a highly reliable contactless temperature probe with high sensitivity, good temperature-induced color discriminability, and economical synthesis has prompted the research community to work in the field of rare-earth-based luminescence thermometry. Moreover, the fast-growing market for optoelectronic devices has increased the demand for tunable color-emitting phosphors. In this study, Dy3+/Eu3+ co-doped SrMoO4 phosphors were developed as tunable color-emitting source and dual-mode luminescence thermometer. A facile and cost-effective auto-combustion method was used to synthesize the phosphors. Our work demonstrates a viable scheme for tailoring the emission of single-phase phosphors by precisely controlling the dopant concentrations and by modulating excitation wavelength. The overall emission is tuned from greenish-yellow to white and greenish-yellow to reddish-orange. A detailed energy transfer process from the host to the Ln3+ ions and between the Ln3+ ions is discussed. Further, anti-thermal quenching in the emission of Dy3+ ion is observed when excited with 297 nm. The dual-mode luminescence thermometry has been studied by analyzing the fluorescence intensity ratio of Dy3+ and Eu3+ ions upon excitation at 297 nm. The maximum relative sensitivity value for 4% Eu3+ co-doped SrMoO4:4%Dy3+ phosphor is 1.46% K−1 at 300 K. Furthermore, the configurational coordinate diagram is presented to elucidate the nature of temperature-dependent emission. Therefore, our research opens up new avenues for the development of color-tunable luminescent materials for various optoelectronic and temperature-sensing applications.

Reengineering the thermometric behaviors of Er3+/Yb3+-codoped Gd2Mo3O12 microparticles via dual-mode luminescence manipulation

Series of Er3+/Yb3+-codoped Gd2Mo3O12 (GMO:Er3+/2xYb3+) microparticles with dual-mode luminescence were fabricated with the assistance of sol-gel method. The phase structure, morphological information, upconversion (UC) and down-shifting luminescence properties of the final products were systematically investigated. At 980 nm light irradiation, strong UC emissions rise in all the products and their intensities depend on the dopant concentration, where the optimum status occurs at x = 0.25 and the two-photon capture procedure results in the UC emission mechanism. Besides, excited at 378 nm, the down-shifting photoluminescence is also gained in resulting samples. By means of the fluorescence intensity ratio technique, the thermometric properties of the studied samples were investigated through analyzing the diverse thermal quenching features of the green emissions from thermally coupled levels of Er3+. When the UC emission is selected, the maximum absolute and relative sensitivities of the GMO:Er3+/2xYb3+ microparticles are 0.0076 and 1.15% K−1, respectively, whereas they shift to 0.0036 and 0.89% K−1, respectively, when the down-shifting photoluminescence is adopted. Note that, the sensor sensitivities of developed microparticles are related to the luminescence mode, while they do not depend on Yb3+ content. These results suggest that the GMO:Er3+/2xYb3+ microparticles are promising thermosensitive luminescent materials for optical thermometry and their thermometric features can be tuned through changing luminescence mode.

Tuning green-to-red ratio of Ho3+ Activated YPO4 dual-mode luminescence through Yb3+ sensitized nano phosphors

INTRODUCTION: Yb3+/Ho3+co-doped YPO4 nano phosphors were synthesized by polyol route, which has both up-conversion (UC) and down-conversion (DC) characteristics and excellent luminescent properties. DC peaks were seen at ~460, ~550, and ~650 nm. METHOD: Switching at ~750 with 300 nm excitation, a very faint P-O charge-transfer (CT) band of the Ho3+ ion and a minute non-radiative resonant energy transfer were observed. We found that YPO4: Yb3+/Ho3+ is an up-converting (UC ) nano phosphor capable of large-scale generation and enhancement of luminescence with green and red emissions.RESULT: Under strong laser irradiation at 980 nm, the up-conversion emission spectrum shows obvious peaks expected for Ho3+ ions at ~550 and ~650 nm. This process produces high-quality nanocrystalline materials with sizes in the range of tens of nm. Considering the results obtained under excitation at 300nm, YPO4:Yb3+/Ho3+ yielded high quantum yield values CONCLUSION: This finding can be used to manufacture high-efficiency phosphors and demonstrates that the nano-phosphor materials covered by this method have a wide range of applications.

Heparin Induced Dual Mode Luminescence Modulation of Organic Nanoparticles and Efficient Energy Transfer.

Amphiphilic di-cationic fumaronitrile derivatives with peripheral n-alkyl chains formed organic nanoparticles (NPs) through self-assembly in aqueous media. The NPs exhibited enhanced luminescence in both steady-state and delayed mode in comparison to their molecularly dissolved state. Due to the presence of the multivalent array of positive charges on their surface, they were found to bind heparin, a bio-polyanion which is routinely employed during surgery as an anticoagulant. The electrostatically driven co-assemblies resulted in a significant enhancement in the steady-state and delayed luminescence of the NPs. This provided a highly sensitive detection of the polyanion in aqueous buffer as well as in highly competitive serum and plasma media. Furthermore, and most notably, the heparin based co-assemblies were found to act as efficient donors exhibiting fluorescence resonance energy transfer (FRET) to acceptor dyes with the energy transfer efficiency reaching up to 88%.

Effect of doping concentration on dual-mode LaVO4:Eu3+ luminescence thermometers

In recent years, we have witnessed tremendous progress in contactless thermal sensing because of the rapid development of luminescence thermometry. Although the thermometric performances of several luminescence thermometers were reported to be comparable with those of convenient contact thermal sensors, there is still room for further improvement. Majority of optical thermometers are based on a single temperature-sensitive luminescence parameter, whereas multiparametric readouts could broaden the working range and enhance the reliability of temperature measurements. Here, we report on a LaVO4:Eu3+ concentration series as dual-mode luminescence thermometers. The effect of the Eu3+ concentration on structural, luminescence, and thermometric properties of the materials was studied in detail. Two dual-excited single band ratiometric strategies and monitoring spectral position of the LaVO4 charge transfer band provide accurate thermal sensing in a wide temperature range. The best thermometric performances of studied phosphors attain Sr = 2.3% K−1 and ΔT = 0.2 K at room temperature.

High-efficiency dual-mode luminescence of metal halide perovskite Cs3Bi2Cl9:Er3+ and its use in optical temperature measurement with high sensitivity

Metal halide perovskites have attracted much attention due to their excellent optical properties and structural tunability. In this work, we synthesized the metal halide perovskite Cs3Bi2Cl9:Er3+ as the activator by solid-phase method using deionized water as the solvent. The phosphor doped with self-sensitizating of Er3+ ions emitted bright green light under the excitation of triple near-infrared laser (808 nm, 980 nm and 1550 nm). Interestingly, the upconversion emission exhibited a strong temperature dependence due to the thermally coupled energy levels 2H11/2 and 4S3/2 of Er3+, therefore is useful for optical temperature measurement. The maximum relative sensitivity in the range of 303–573 K is 1.40%K−1 (303 K, 808 nm), 1.38%K−1 (303 K, 980 nm), 1.50%K−1 (303 K, 1550 nm), respectively. By using fluorescence intensity ratiometry (FIR) methods, Cs3Bi2Cl9:Er3+ phosphor showed excellent accuracy and sensitivity and was compared very favorably with the reported temperature measurement materials. We anticipate that this new phosphor may have a range of applications in multi-mode luminescence and multi-excited light source temperature measurement.

Cancer bioimaging using dual mode luminescence of graphene/FA-ZnO nanocomposite based on novel green technique

Graphene based nanomaterials are explored in the field of cancer bioimaging and biomedical science and engineering. The luminescent nanostructures with a low toxicity and high photostability can be used as probes in bioimaging applications. This work is aimed to prepare graphene/folic acid-zinc oxide (GN/FA-ZnO) nanocomposite with dual-mode emissions (down-conversion and up-conversion) to be used in cancer bioimaging. The dual mode emissions offer long luminescence lifetime, multicolor emissions detected by the naked eyes after excitation and narrow band absorption and emission spectra. ZnO nanospheres and nanorods structures were prepared using co-precipitation technique and were conjugated with FA to separate the bulk graphite layers electrostatically into GN. The optical, morphological, surface charge and structural properties of the prepared nanostructures were investigated and discussed using different characterization techniques such as UV–visible spectroscopy, photoluminescence (PL) spectroscopy, scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), Zeta potential, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD), and Fourier transform infrared (FTIR). GN/FA-ZnO nanocomposites were injected into Swiss albino mice implanted with Ehrlich Tumor and the bioimaging was investigated using photon imager and digital camera. The results showed clear fluorescence and confirmed that the green design of GN/FA-ZnO nanocomposite with targeting behavior was capable of selective bioimaging of the tumor. This study presented a novel dual mode emission nanocomposite for tumor targeting and is a promising strategy for the fabrication of a new design of spectral encoding.

Dual-mode luminescence anti-counterfeiting and white light emission of NaGdF4:Ce,Eu,Tb/carbon dot hydrophilic nanocomposite ink.

NaGdF4:Ce,Eu,Tb nanocrystals were successfully prepared by a one-step hydrothermal method with Ce3+ ions as sensitizers, Eu3+ and Tb3+ ions as activators, and polyethylenimine (PEI) as surfactants. Color-adjustable fluorescence emission was achieved by the energy transfer effect between rare earth ions. Blue fluorescent carbon quantum dots (CDs) with a double UV response under 254 nm and 365 nm excitation were synthesized by a one-step hydrothermal method. A hydrophilic NaGdF4:Ce,Eu,Tb/CD composite ink was prepared by an easy physical mixing method. Because of the electrostatic self-assembly effect, the color adjustable luminescence was achieved in a few seconds, and the white light emission with color coordinates of (0.32, 0.32) was obtained. A dual-mode luminescence anti-counterfeiting pattern was designed and achieved by excitation with ultraviolet light at 254 nm and 365 nm.

Designing dual-emission phosphors for temperature warning indication and dual-mode luminescence thermometry.

Color tunable phosphors of Mn4+ and Tb3+ co-doped double-perovskite SrGdLiTeO6 (SGLT) were synthesized in this work. The crystal parameters and photoluminescence performances were investigated in detail. By taking advantage of the different thermal quenching strengths between Mn4+ and Tb3+ ions, the emission color of SGLT:0.7%Mn4+/1%Tb3+ changed from red to green, which could be used for high-temperature temperature warning indication. Moreover, according to the luminescence intensity ratio (LIR) technique, wide temperature-range optical thermometry was developed and further, the maximum relative sensitivity (SR1) value of the SGLT:0.7%Mn4+/5%Tb3+ phosphor was determined to be 1.49% K-1 at 560 K. On the other hand, the sensing properties were also analyzed based on the temperature-dependent lifetime method. The most interesting thing is that the maximum SR2 value reached 1.88% K-1 at 573 K. This work proved that the Mn4+ and Tb3+ co-doped double-perovskite SrGdLiTeO6 could be potentially used in temperature warning indication and high sensitivity luminescence thermometry.

Simple synthesis of dual-emission CsPbBr3@EuBTC composite for latent fingerprints and optical anti-counterfeiting applications

As an emerging optical material, all-inorganic perovskite quantum dots (QDs) have been successfully applied in some fields. However, inherent ionic properties of perovskite QDs lead to poor stability of water and heat which severely hinders the further industrial applications. Therefore, the incorporation of Metal-Organic Framework (MOF) into QDs to obtain CsPbX 3 @MOF composite is developing to improve the stability of all-inorganic perovskite QDs. In this work, a simple and fast method was developed to synthesize a CsPbBr 3 @EuBTC composite. The water stability and thermal stability of the CsPbBr 3 @EuBTC composite have been improved compared to pure CsPbBr 3 QDs. Simultaneously, luminescent properties and promising latent fingerprints and optical anti-counterfeiting applications of the CsPbBr 3 @EuBTC composite are further explored. Under fluorescent interference, it still shows excellent luminescence sensitivity and anti-interference ability. The CsPbBr 3 @EuBTC composite displays dual-mode luminescence as excited under the 365 nm or 254 nm ultraviolet (UV) excitation wavelength. Adjusting the ratio of CsPbBr 3 QDs to EuBTC in the CsPbBr 3 @EuBTC composite can also achieve multi-color luminescence. Therefore, it is expected that CsPbBr 3 @EuBTC can be applied to latent fingerprints and multi-mode optical anti-counterfeiting materials.

Simultaneous influence of Mg2+ and Sc3+ co-doping on upconversion luminescence and optical thermometry in β-NaYF4: Yb3+/Ho3+ microphosphor

A series of xMg2+/ySc3+ co-doped β-NaYF4:0.2Yb3+/0.02Ho3+ (x = y = 0 −0.2) upconversion (UC) green phosphors are synthesized using EDTA-assisted hydrothermal method. The structure, morphology and elemental compositions are investigated in detail using different experimental techniques. The lengthwise suppression of crystal due to co-doping is associated to the kinetics involved in the crystal growth in presence of Mg2+/Sc3+. The effect of Mg2+/Sc3+ co-doping on the UC green emission of β-NaYF4:0.2Yb3+/0.02Ho3+ microphosphors is studied and about 31-fold enhancement in the green emission (5F4,5S2→5I8) is observed for the 0.08Mg2+/0.12Sc3+ co-doped phosphor. The downconversion properties of the phosphors is also discussed to showcase the dual mode luminescence. The temperature sensing performance is investigated using luminescence intensity ratio (LIR) technique for non-thermally coupled levels (5F5/5F4,5S2) of Ho3+ ions and maximum relative sensitivity of 0.258% K−1 at 374 K is obtained for the optimized phosphor. The microphosphor can be sustained at high temperature as the UC emission intensity retains about 65% and 36% at 423 K and 574 K. From chromaticity diagram, the maximum color purity of 91.37% is obtained for 0.08Mg2+/0.12Sc3+ doping concentration. The estimated thermal parameters and color purity of Mg2+/Sc3+ co-doped β-NaYF4:0.2Yb3+/0.02Ho3+ UC phosphors suggest their applicability in fabricating temperature sensors and LEDs.

Upconversion luminescence, scintillation properties and optical thermometry behaviors of Tm3+, Yb3+: Gd2Zr2O7 nanocrystals

The development of multifunctional nanocrystals has attracted growing interest lately in the biological and medical sciences. Herein, the dual-mode luminescence properties and optical thermometric performances of Tm3+, Yb3+: Gd2Zr2O7 nanocrystals synthesized by a facile hydrothermal method are investigated systematically. Upon 980 nm excitation, the upconversion (UC) luminescence spectra of the obtained samples consist of blue (485 nm), red (655 and 681 nm), and near-infrared (785 nm) emission bands of Tm3+ ions. Diversely, the X-ray excited luminescence (XEL) spectra contain a strong ultraviolet (UV) emission from Gd3+ ions (314 nm), a weak defect-related emission band (400–600 nm), and several tiny emissions from Tm3+ ions. To realize the optical thermometry in the biological window, the luminescence intensity ratio (LIR) between 3F2,3 → 3H6 (681 nm) and 1G4→3F4 (655 nm) transitions is employed for temperature sensing, giving high absolute and relative sensing sensitivities (Sa-max = ∼1064 × 10−4 K−1, Sr-max = ∼2.32%K−1). Therefore, the present Tm3+, Yb3+: Gd2Zr2O7 nanocrystals could be useful in optical thermometry, photodynamic therapy, and X-ray imaging.