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In the framework of luminescent rare-earth-doped glasses for near-infrared applications, TiO2-containing inorganic glasses have been recently demonstrated to be a promising alternative to commercially used high-phonon SiO2-based glasses. This study investigates the effect of TiO2 concentration on the near-infrared spectroscopic properties of Yb3+ ions in multicomponent titanate–germanate glasses. A series of glass samples in the xTiO2-(60−x)GeO2-BaO-Ga2O3-Yb2O3 system (x ranging from 0 to 50 mol%) were synthesized using the melt-quenching technique. X-ray diffraction analysis confirmed the fully amorphous nature of the fabricated titanate–germanate samples. Fundamental spectroscopic properties of Yb3+-doped titanate–germanate system consisting of absorption spectra, near-IR emission spectra, and luminescence decay curves have been determined based on measurement using optical spectroscopy. The intensity of the emission band at 1 µm due to the 2F5/2 → 2F7/2 laser transition of Yb3+ ions increases by over 2.3-fold (TiO2 as the network former) compared to a barium gallo-germanate sample without TiO2. Our previous studies indicate that Yb3+-doped titanate–germanate glass is a promising optical material and could be successfully applied to laser technology. [ABSTRACT FROM AUTHOR]

Weak luminescence of the small‐sized lanthanide‐doped nanoparticles has limited their applications long. In recent years, there is a growing interest in luminescence thermal enhancement in small‐sized upconversion nanoparticles (UCNPs). The mitigation of surface quenching effects and the improvement of energy transfer (ET) are two convincing explanations for this phenomenon. A systematical investigation on the luminescence dynamics of Yb3+ is implemented. ET rate and then the proportion of ET increases greatly with rising temperatures in Yb3+/Tm3+ codoped system, while an alternative trend can be summarized in Yb3+/Er3+ one. Based on these findings, therefore it can be concluded that the surface quenching mitigation related to the desorption of water molecules on the surface is a common mechanism of the luminescence thermal enhancement. But ET related to the thermally‐activated surface phonons is a special case, it does play a positive role in Yb3+/Tm3+ system. These findings not only explain the upconversion luminescence thermal enhancement in Yb3+/Tm3+ system is more significant but also help to understand thermal enhancement and benefit highly‐sensitive temperature probe design. [ABSTRACT FROM AUTHOR]

Thermal quenching of luminescence materials poses a major obstacle to the technological application of luminescence thermometry. It still remains challenging to attain thermally enhanced light emissions, especially in the second near‐infrared window (NIR‐II). Herein, an anomalous thermal dependence of NIR‐II luminescence in the negative thermal expansion (NTE) Sc2Mo3O12:Er3+/Ho3+ nanocrystals is reported. Mechanistic investigations affirm that Ho3+ ion can work as an energy reservoir and back‐transfer to Er3+ ion with the assistance of lattice phonon at elevated temperatures. Moreover, the Ho3+‐mediated energy feedback is strengthened by the thermal contraction between dopant ions, thereby enabling a remarkable thermal enhancement of NIR‐II emission over 11‐fold. The opposite thermal response of Er3+ and Ho3+ emissions is harnessed for NIR‐II ratiometric thermometry, registering exceptional performance in a high‐temperature regime (Sr = 1.71% K−1, δT = 0.2 K at 513 K). These findings may inspire new insights for addressing the thermal quenching of NIR‐II luminescence, which also raises exciting opportunities for flexible thermometry in complex settings. [ABSTRACT FROM AUTHOR]

This work reports the preparation by co‐precipitation method of [Zn2Al0.95:Ln0.05(OH)6](HMA)0.21·(H2O)x, where x = 1.0–1.7 and Ln3+: Sm3+, Eu3+, Gd3+, Tb3+ and Dy3+, doped trivalent lanthanide ions (Ln3+) intercalated with mellitate (HMA5−) anions in the interlayer gallery. The results indicate that the Ln3+ ions and the organic anion are effectively introduced into the material without significantly losing the structural properties of the layered double hydroxydes (LDH). In situ measurements reveal slight changes in the luminescent properties assigned to the nucleation and growth processes of the LDH. Ex situ experiments show that the photophysical properties also changed after the drying process, indicating significant interactions of the mellitate anion in the materials. LDH‐HMA:Eu3+ and LDH‐HMA:Tb3+ exhibit high luminescence intensity in the red and green spectral regions due to the 5D0→7F0‐6 and 5D4→7F6‐0 transitions, respectively. The LDH‐HMA doped with different ratios Eu3+/Tb3+ presenting emission colors from red to green are also investigated. Surprisingly, the unexpected afterglow blue luminescence from the LDH‐HMA doped with Gd3+ ion is ascribed to the phosphorescence T→S0 transition. Finally, obtaining three red, green and blue luminophores based on the same type of material represents an effective strategy toward white‐light emission realized by mixing three different LDHs materials based on Ln3+ ions. [ABSTRACT FROM AUTHOR]

Lanthanide‐doped nanoparticles (NPs) exhibit temperature‐dependent luminescence, enabling the design of luminescent nanothermometers for industrial and medical applications. This research demonstrates the temperature‐sensing properties of NaYF4:7.5%Er3+@NaYF4 and NaErF4@NaYF4 NPs, which have a hexagonal shape and average size of 17 nm. Their core@shell structure is confirmed using high‐resolution transmission electron microscopy, and they exhibit intense upconversion (UC) emission under 1532 nm excitation in H2O and D2O colloids. The recorded spectra show Er3+ emission bands with varying intensity ratios depending on the Er3+ concentration, chosen solvent, and temperature. The spectroscopic properties of the studied NPs allow for their excitation and observation of emission within biological windows, which makes them useful for bio‐related applications. The emission of prepared NPs is analyzed as a function of temperature from 298 up to 358/363 K in H2O and D2O. The ratios for thermally‐coupled levels  and non‐TCLs and their relative sensitivities are studied. For the high dopant concentration sample in water, the O─H vibrations and blue shift in the absorption spectrum lead to a record relative sensitivity of 2.50% K−1 (at 363 K) for the 2H11/2/4I11/2 ratio. The use of synthesized NPs for bioimaging under 1550 nm excitation is also demonstrated to observe their accumulation in the guts of Daphnia magna. [ABSTRACT FROM AUTHOR]

The longitudinal and transverse nuclear magnetic resonance relaxivity dispersion (NMRD) of 1H in water induced by the paramagnetic relaxation enhancement (PRE) of dissolved lanthanide ions (Ln3+) can become very strong. Longitudinal and transverse 1H NMRD for Gd3+, Dy3+, Er3+ and Ho3+ were measured from 20 MHz/0.47 T to 1382 MHz/32.5 T, which extended previous studies by a factor of more than two in the frequency range. For the NMRD above 800 MHz, we used a resistive magnet, which exhibits reduced field homogeneity and stability in comparison to superconducting and permanent NMR magnets. These drawbacks were addressed by dedicated NMRD methods. In a comparison of NMRD measurements between 800 MHz and 950 MHz performed in both superconducting and resistive magnets, it was found that the longitudinal relaxivities were almost identical. However, the magnetic field fluctuations of the resistive magnet strongly perturbed the transverse relaxation. The longitudinal NMRDs are consistent with previous work up to 600 MHz. The transverse NMRD nearly scales with the longitudinal one with a factor close to one. The data can be interpreted within a PRE model that comprises the dipolar hyperfine interactions between the 1H and the paramagnetic ions, as well as a Curie spin contribution that is dominant at high magnetic fields for Dy3+, Er3+ and Ho3+. Our findings provide a solid methodological basis and valuable quantitative insights for future high-frequency NMRD studies, enhancing the measurement accuracy and applicability of PRE models for paramagnetic ions in aqueous solutions. [ABSTRACT FROM AUTHOR]

Lanthanide-doped β-Ca2SiO4 has been regarded as a promising material for use in light-emitting diode (LED) phosphors. Nevertheless, the performance of these luminescent materials activated by lanthanide ions depends strongly on the host matrix. The challenge lies in controlling the phase under ambient conditions in a material that exists in five polymorphic forms. Herein, we report the synthesis of β-Ca2SiO4 containing Ce and Eu ions via the Sol–Gel method. The pure and doped samples were characterized using thermogravimetric (TG) and differential thermal (DT) analysis, X-ray diffraction (XRD) and Rietveld–XRD analysis, scanning electron microscopy (SEM), X-ray absorption near edge structure (XANES), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and defect calculations. XRD analyses show the predominant formation of the β-phase. Morphological analyses by SEM show smaller particle sizes in Ce- and Eu-doped β-Ca2SiO4 than pure samples. This result suggests that Ce3+ is more efficient at stabilizing the β-Ca2SiO4 polymorph. The PL emission of the β-Ca2SiO4:Eu, excited at 393 nm, provides evidence about the existence of two nonequivalent sites, with one of them evolving to a high symmetry site and the other one remaining in a low symmetry. PL results are corroborated by defect calculations in which it is evident that both Eu3+ and Ce3+ ions prefer to be incorporated into the two Ca2 sites compensated by a Ca1 vacancy, including a probable change in the coordination number of the Eu3+ ion. The abrupt distortion of one of the Eu3+ sites is accompanied by the high 5D0 → 7F4 transition. Also, we present XANES and XPS analyses combined with defect calculations for Eu2+ and Ce4+ ions to discuss the likely coexistence of valency states in the host matrix. Lastly, the results offer insights into improving the performance of phosphor-converted white LEDs. [ABSTRACT FROM AUTHOR]

Lanthanide ions doped in perovskite (LIDP) nanocrystals (NCs) provide an effective way to utilize the emission of lanthanide metals in a solution‐processable way, combining the theoretical photoluminance quantum yield (PLQY) of ≈200%. To utilize advantages, LIDP‐NCs have inspired studies exploring the fundamental physics of energy transfer, including the up‐conversion or down‐conversion process, and the optoelectronic applications of solar cells and white light‐emitting didoes. This review broadens the scope of LIDP nanocrystal matrix semiconductors in electroluminescence devices in the near‐infrared (NIR) range (>900 nm). A research is summarized on the synergistic effect of lanthanide ions and perovskite matrix in the near‐infrared region, and discuss from the perspective of fabrication of lanthanide‐based electroluminescent devices using perovskite materials as the matrix. The multiple optical transitions, bandgap tunability, and quantum‐cutting effect to provide a tutorial on understanding LIDP‐NCs are started. The details of synthesizing LIDP materials and aim to lay the foundation for preparing NIR electroluminescent devices with high efficiency and application value are then illustrated. The scientific issues that limit the performance of LIDP NCs‐based electroluminescent devices and discuss the potential strategies for the future development of LIDP material are focused on. [ABSTRACT FROM AUTHOR]

Förster resonant energy transfer (FRET) is a well-known and important phenomenon in physics, chemistry, and biology, which plays a crucial role in various photofunctional systems, including photovoltaics, and lighting, and sensing where molecular distances and interactions are probed. This paper presents a systematical investigation of the construction of interfacial FRET between carbon dots (CDs) and NaYF 4 :Eu3+ nanoparticles (NPs) via various synthesis routes. The interfacial FRET was found to take place from CDs to Eu3+ in the wet-mixed and the reacted nanocomposites owing to the presence of strong interfacial interactions, as evidenced by the results of Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). By employing CDs-sensitized NaYF 4 :Eu3+ NPs as a model system, we were able to elucidate the intricate FRET mechanism between CDs and NaYF 4 :Eu3+ NPs. Surprisingly, the reacted nanocomposite exhibits remarkable photo- and thermal-stability, as well as high resistance to thermal degradation, demonstrating the robustness of the interfacial FRET in enhancing Eu3+ emission intensity. The study presents a convenient and versatile approach to achieving interfacial FRET based on CDs nanocomposites, which have a promising potential application in solid-state lighting and biomedicine. [ABSTRACT FROM AUTHOR]

Rare-earth elements (REEs) are critical to modern industry but difficult to separate due to their subtle and monotonic changes in physicochemical properties. MoS2-based two-dimensional (2D) materials offer novel opportunities for enhancing REE separation, exhibiting a distinct volcano-shaped transport performance distribution that peaks at Sm3+. However, the specific contributions of thermodynamic and kinetic factors to ion transport within 2D confinement remain unclear. In this study, we conducted a series of non-equilibrium all-atom molecular dynamics (MD) simulations to explore the effects of interlayer spacing and external pressure on the transport of lanthanide ions in Å-scale acetate functionalized 2D MoS2 (MoS2-COOH) channels. We examined ion entry and permeation rates, water flux, dehydration, and binding modes. The simulation results reveal that the transport trends of lanthanide ions are jointly driven by the dehydration degree and the relative-binding strengths of ions to water and to the acetate within the 2D channels. Notably, the dehydration pattern of lanthanide ions during permeation is closely linked to kinetic factors. Overall, this study provides a detailed atomistic understanding of the mechanisms underlying lanthanide ion transport under confinement. These findings point to the significant potential for tuning confinement and chemical functionalization within Å-scale channels for more efficient REE separation. [ABSTRACT FROM AUTHOR]

Lanthanide ions-doped fluoride nanocrystals have excellent application prospect. However, low photoluminescence quantum yield (PLQY) is usually along with lanthanide ions-doped fluoride nanocrystals owing to their low molar absorptivity and narrow absorption band. In order to increase the absorption cross section of Ln3+ in fluoride nanocrystals, a facile synthesis strategy to enhance luminescence of AF 2 : Ln3+ (A = Ca, Sr; Ln = Eu, Tb) by the use of carbon dots (CDs) has been developed in this work. A series of characterizations including TEM, XRD, FTIR and XPS demonstrated that the CDs have been successfully combined with the surface of AF 2 : Ln3+ nanocrystals. The combination of CDs has little influence on the microstructure and phase structure of AF 2 : Ln3+, and CDs@AF 2 : Ln3+ nanocrystals have uniform and regular shape with cubic phase. CDs are used as a broadband sensitizer and lead to the broadband excitation of Ln3+, resulting in the enhancement around 10-fold of Ln3+ luminescence emission in AF 2 : Ln3+ nanocrystals after CDs combination. The corresponding PLQY increases almost three times, and the luminescence enhancement mechanism by combining CDs is proposed. In addition, the CDs@AF 2 : Ln3+ nanocrystals are used to prepare CDs@AF 2 : Ln3+/PVA films, which exhibits excellent luminescence properties under the excitation of UV light. This work provides a superior method for enhancing the luminescence properties of lanthanide ions-doped nanocomposites and demonstrates practical potential as promising candidates for light-converting thin films. [Display omitted] • CDs can be as a broadband sensitizer to increase the absorption cross section of Ln3+ in AF 2 : Ln3+ nanocrystals. • The fluorescence emission of AF 2 : Ln3+ (A = Ca, Sr; Ln = Eu, Tb) increases by about 10 times by combining CDs. • CDs are able to capture the electrons of Ln3+ and transfer energy to Ln3+ in AF 2 : Ln3+ nanocrystals. • CDs@AF 2 : Eu3+/PVA film can be fabricated and converts UV to red light. [ABSTRACT FROM AUTHOR]

Enantiomeric molecules generally play distinct functions in chemistry, biology, and pharmacology. Similar physical and chemical properties of chiral analytes lay difficulty in discrimination and quantification of the enantiomers. We report herein an efficient approach of increasing the chiral sensing ability of β-cyclodextrin (β-CD), a widely used host molecule, in the host-guest chemistry by magnetic anisotropy. A rigid and chiral lanthanide binding tag was attached to the β-CD to amplify the changes of nuclear magnetic resonance (NMR) signals in the host-guest recognition process. The installation of the paramagnetic lanthanide ion in β-CD greatly enhances the enantiomeric discrimination up to 30-fold in comparison with the diamagnetic β-CD reference. In addition, the magnitude of the paramagnetic effects is tunable according to the diverse range of paramagnetic strength of the lanthanide series. The reported method significantly increases the chiral sensing ability of β-CD, which can be applied to other host molecules. The transferred paramagnetic effects, pseudocontact shifts (PCSs) and paramagnetic relaxation enhancements (PREs), from the host to the guest molecules, are valuable structural restraints to determine the absolute stereochemistry of the chiral analytes. The strategy does not need modification of the analytes and is complementary to the reported analytical methods that rely on the functionalization of the chiral analytes. [ABSTRACT FROM AUTHOR]

In recent years, the pursuit of luminescent thermometer probes with low cost and high sensitivity has become a significant research challenge. This work proposes a strategy that employs lanthanide ions and carbon dots with dual-emission with diverse temperature dependencies to achieve high-temperature sensitivity. Specifically, the fabrication of dual-activated temperature probes has been achieved using NaMgF3:Eu3+/carbon dot nanocomposites through a simple coprecipitation process at room temperature. The optical temperature sensor, NaMgF3:Eu3+/carbon dot, was developed using Eu3+ emission as an internal standard and carbon dot as the temperature signal. The sensor exhibits a substantial absolute sensitivity of 8.3 ± 0.2%K–1 and a relative sensitivity of 2.0 ± 0.1%K–1, both at 300 K, making it a promising candidate for physiological thermometry. Within the temperature range of 300–440 K, the NaMgF3:Eu3+/carbon dot probe shows a relative sensitivity of better than 1.0%K–1 with good excellent repeatability as well as a nearly linear relationship between the Commission Internationale de l'Echlairage chromaticity coordinates of the observed fluorescent color change. The feasibility of the proposed strategy has also been verified by modifying lanthanide ions, e.g., Tb3+. It is anticipated that this pilot study will serve as a springboard for research on dual-mode nanothermometers with superior ratiometric and colorimetric performance. [ABSTRACT FROM AUTHOR]

Rare earth doped luminescent sensing materials as non-contact thermometers have attracted extensive research interests due to their wide applications in areas like military, medical care, aerospace, etc. How to expand the working temperature range and improve the sensitivity has become the focus. In this work, we synthesized a series of apatite-structured luminescent temperature sensors M 2 La 7.9 Ce 0.1 (SiO 4) 6 O 2 (M = Ca, Sr, Ba) via isomorphic substitution. By monitoring the differential changes of emission intensities from Ce3+ at the 7-coordinate and 9-coordinate site respectively when temperature varies, the real-time temperature can be determined. These materials were proven to possess the maximum absolute sensitivity up to 0.825 × 10−3 K−1, 2.63 × 10−3 K−1 and 4.33 × 10−3 K−1, respectively. Meanwhile interesting regular patterns were observed for their temperature sensitivities with the substitution of Ca, Sr and Ba. Furthermore, through studying the temperature sensitivity of Ba 2 La 8 (SiO 4) 6 O 2 : x Ce3+ samples with different concentrations, it was found that when the Ce3+ content was at the optimal doping concentration of 0.7, the absolute sensitivity of the sample reached 14.64 × 10−3 K−1 at 573 K. This finding has opened up a new avenue for designing fluorescent temperature sensors. Synopsis: In this work, Ce3+ were doped into a series of phosphor-structured matrices containing two cationic sites (7-coordinated Ce1 and 9-coordinated Ce2 sites) via the solid-state high-temperature method. Due to the different temperature dependencies of luminescence intensities between the two Ce3+ sites, their intensity ratio could be used for temperature calibration. [Display omitted] [ABSTRACT FROM AUTHOR]

The ZnS: Ho3+, Yb3+, Mn2+ nanomaterials fabricated by the co-precipitation method have the zinc-blende structure with the crystallite size about 90 ∼ 100 nm. The X-ray diffraction (XRD), the scanning electron microscope (SEM) and the transmission electron microscope (TEM) characterizations confirm that the doping of the Mn2+ has less effect on the structure of the ZnS: Ho3+, Yb3+, Mn2+ nanomaterials. With the excitation of a 978 nm laser, the upconversion (UC) emissions of the ZnS: Ho3+, Yb3+, Mn2+ nanomaterials include two emission bands located at 551 and 664 nm, which correspond to the transitions 5F4 (5S2)→5I8 and 5F5→5I8 of the Ho3+ ions. The UC emission characterization confirms that the UC emission of the ZnS: Ho3+, Yb3+ nanomaterials can be modulated by the doping of the Mn2+ ions, the increase of the incident laser power and the change of the laser pulse-width. The red emission of the ZnS: Ho3+, Yb3+ nanomaterials particle will increase significantly with the incorporation of the Mn2+ ions. The incident laser power and the laser pulse-width also can modulate the intensity ratio G/R of the green to the red. With the increase of the incident laser power, the emission intensity ratio G/R will also increase. With the increase of laser pulse-width from 0.2 to 0.8 ms, the above intensity ratio G/R will decrease significantly. The modulation between the green and red emission is due to the energy transfer from the 5F4 (5S2) state to the 5F5 state of the Ho3+ ions through the state 4T1 of the Mn2+ ions. [ABSTRACT FROM AUTHOR]

A simple, sensitive dual-emission probe was developed for the detection of phosphate (Pi). The probe Tb-BTB/DPA was synthesized by mixing dual-ligand, 1,3,5-tri(4-carboxyphenyl) benzene (H3BTB) and dipicolinic acid (DPA), with metal ions Tb3+ in ethanol–water solution at 40℃ for 2 h. Tb-BTB/DPA exhibits two emission peaks, the emission at 362 nm is attributed to H3BTB, an energy transfer between Tb3+ nodes, and DPA further enhances the fluorescence of Tb3+ at 544 nm. Pi competes with ligand H3BTB to coordinate Tb3+, resulting in partial collapse of the Tb-BTB/DPA structure and interrupting the electron transfer between H3BTB and Tb3+. Therefore, the emission at 362 nm is enhanced, while the emission at 544 nm is unchanged, and a ratiometric fluorescence method is developed to detect Pi. Tb-BTB/DPA exhibits good linearity within the Pi concentration range (0.1–50 µmol/L), and the detection limit was 25.8 nmol/L. This study provides a new way to prepare probes with dual emission sensing properties. [ABSTRACT FROM AUTHOR]

Lanthanide ions, as dopants, have evoked widespread research interest owing to the rich optical, magnetic, and electrical properties, but their luminescent intensity is always limited by typical concentration quenching. Herein, a holmium‐based double perovskite of Cs2NaHoCl6 is reported, which surprisingly breaks through this barrier and achieves efficient red‐NIR emission by virtue of the large unit cell, low phonon energy, high content of activators, and cross relaxation phenomenon between Ho3+. The heavy Ho3+ also endows the intriguing half‐metallic nature with a down‐spin conducting band and an up‐spin insulating band. After performing ion doping on crystallographic sites of Na+ and Ho3+, the photoluminescence quantum yield of such red‐NIR emitter under 450 nm excitation is dramatically promoted to 82.3%, benefiting from the improved crystal field environment that alleviates the parity forbidden rule and suppresses non‐radiative recombination loss. Furthermore, the heat‐favorable phonon‐assisted population processes enable the robust photostability against thermal quenching. By combining a 450 nm chip, the red‐NIR light‐emitting diodes are fabricated, in which the wide‐coverage NIR emissions are ideally suited for medical light source, night vision, nondestructive examination, and transmission imaging. It is believed that this work will open an avenue for enhancing the fluorescence of lanthanide ions and developing advanced spintronic materials. [ABSTRACT FROM AUTHOR]

[Display omitted] Lanthanide complexes [CpXLnCl 2 (Me 3 tach)] n (Ln = Tb, Gd; CpX = Cp, Cp Ph 2 , Cp Ph 4 ; Me 3 tach = 1,3,5-trimethyl-1,3,5- triazacyclohexane; n = 1, 2), containing cyclopentadienyl (Cp), 1,3-diphenylcyclopentadienyl (Cp Ph 2) and tetraphenyl- cyclopentadienyl (Cp Ph 4) anions as ν-bonded antenna ligands, have been synthesized. A combined analysis of quantum chemical, optical and X-ray diffraction data has shown that the introduction of phenyl groups into the Cp ring leads to the inevitable appearance of intraligand charge transfer states due to the nonequivalence of the phenyl rings. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Luminescent materials that display quick spectral responses to thermal stimuli have attracted pervasive attention in sensing technologies. Herein, a programmable luminescence color switching in lanthanide‐doped LiYO2 under thermal stimuli, based on deliberate control of the monoclinic (β) to tetragonal (α) phase transition in the crystal lattice, is reported. Specifically, a lanthanide‐doping (Ln3+) approach to fine‐tune the phase‐transition temperature in a wide range from 294 to 359 K is developed. Accordingly, an array of Ln3+‐doped LiYO2 crystals that exhibit progressive phase transition, and thus sequential color switching at gradually increasing temperatures, is constructed. The tunable optical response to thermal stimuli is harnessed for colorimetric temperature indication and quantitative detection, demonstrating superior sensitivity and temperature resolution (Sr = 26.1% K−1, δT = 0.008 K). The advances in controlling the phase‐transition behavior of luminescent materials also offer exciting opportunities for high‐performance personalized health monitoring. [ABSTRACT FROM AUTHOR]

Compared with the conventional first near-infrared (NIR-I, 700–900 nm) window, the short-wave infrared region (SWIR, 900–1700 nm) possesses the merits of the increasing tissue penetration depths and the suppression of scattering background, leading to great potential for in vivo imaging. Based on the limitations of the common spectral domain, and the superiority of the time-dimension, time-resolved imaging eliminates the autofluorescence in the biological tissue, thus supporting higher signal-to-noise ratio and sensitivities. The imaging technique is not affected by the difference in tissue composition or thickness and has the practical value of quantitative detection in vivo. Almost all the relevant time-resolved imaging was carried out around lanthanide-doped upconversion nanomaterials, owing to the advantages of ultralong luminescence lifetime, excellent photostability, controllable morphology, easy surface modification and various strategies of regulating lifetime. Therefore, this review presents the research progress of SWIR time-resolved imaging technology based on nanomaterials doped with lanthanide ions as luminescence centers in recent years. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) cells are still the most used energy generation devices for aerospace applications. Although multijunction solar cells represent the standard commercial technology for powering spacecraft, spacecraft companies are still using Si-based PV cells to decrease the cost of satellites at the expense of efficiency and energy generation losses. One of the limitations on solar energy conversion is the mismatch between the solar spectrum and the absorption of the PV technology in use. Thus, strategies to overcome this have been proposed, namely the use of luminescent downshifting layers (DSLs) which are very promising to shape the incident sunlight. In this sense, downshifting materials with absorption in the UV/blue spectral region have been privileged considering the solar spectrum in space environments (AM0 solar spectrum), in which the UV component is larger than that on Earth surface (AM1.5 solar spectrum). Here, we propose the use of Eu3+-doped di-ureasil organic-inorganic hybrid materials as DSLs to be used on large area Si-based PV cells (∼0.1 m2) for space applications. Electrical measurements on the PV cell, done before and after the deposition of the DSLs, confirm the positive effect of the coatings on the device performance, with a relative increase on the generated electrical power of ∼2.6 %. Here, we report, for the first time, a DSL specifically designed for space applications and with the largest active area reported so far.

Recent progress on the temporal response (TR) of lanthanide‐doped upconversion luminescence (UCL) has enriched the means of UCL regulation, promoted advanced designs for customized applications such as biological diagnosis, high‐capacity optical coding, and dynamic optical anti‐counterfeiting, and pushed us to reacquaint the dynamic responses of sensitizer/activator ions in UCL systems. In particular, the lifetime of UCL should be revisited after discovery of novel experimental phenomena and luminescence mechanisms, i. e. it should be understood as the collective TR (in the decay edge) of all the involved ions rather than the reciprocal of the radiative rate of an individual ion. In this Concept, we retraced the latest understanding of the dynamics in UCL with special attention to the relationship between excitation and emission, means of TR regulation, and discussed existing challenges. It is expected to provide some fundamental insights to deepened understanding, further regulation, and frontier applications of TR features of UCL. [ABSTRACT FROM AUTHOR]

We obtained thorough insight into the capabilities of various computational methods to account for the ligand field (LF) regime in lanthanide compounds, namely, a weakly perturbed ionic body and quasidegenerate orbital multiplets. The LF version of the angular overlap model (AOM) was considered. We intentionally took very simple idealized systems, the hypothetical [TbF]2+, [TbF2]+ and [Tb(O2NO)]2+, in order to explore the details overlooked in applications on complex realistic systems. We examined the 4f and 5d orbital functions in connection to f–f and f–d transitions in the frame of the two large classes of quantum chemical methods: wave function theory (WFT) and density functional theory (DFT). WFT methods are better suited to the LF paradigm. In lanthanide compounds, DFT faces intrinsic limitations because of the frequent occurrence of quasidegenerate ground states. Such difficulties can be partly encompassed by the nonstandard control of orbital occupation schemes. Surprisingly, we found that the simplest crystal field electrostatic approximation, reconsidered with modern basis sets, works well for LF parameters in ionic lanthanide systems. We debated the largely overlooked holohedrization effect that inserts artificial inversion symmetry into standard LF Hamiltonians.

In recent years, lanthanide doped materials have been extensively studied in the field of fluorescence temperature sensing due to their abundant emission levels and sensitive thermal response. Temperature sensing based on fluorescence intensity ratio (FIR) of upconversion nanoparticles has the advantages of fast temperature response, non-aggressiveness, and high spatial resolution. However, the most reported FIR sensing has limited sensitivity, probably due to the use of thermal coupling levels. Herein, we report a novel FIR temperature measurement based on non-thermal coupling levels of NaGdF 4 :Yb3+/Er3+@NaGdF 4 @NaGdF 4 :Yb3+/Tm3+ core-shell-shell nanostructure, which has high sensitivity and robustness simultaneously. The relative sensitivity based on I 801 / I 654 and I 801 / I 841 of Tm3+ to Er3+ can reach up to 4.56 (303 K) and 3.82% K−1 (313 K), respectively. Between them, FIR of I 801 / I 841 is independent of excitation power and time. These results show the great potential of FIR based on non-thermal coupling levels in high-sensitive and robust temperature sensors. [ABSTRACT FROM AUTHOR]

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A series of novel 3D coordination polymers [Ln2(Qdca)3(H2O)x]·yH2O (x = 3 or 4, y = 0–4) assembled from selected lanthanide ions (Ln(III) = Nd, Eu, Tb, and Er) and a non-explored quinoline-2,4-dicarboxylate building block (Qdca2− = C11H5NO42−) were prepared under hydrothermal conditions at temperatures of 100, 120, and 150 °C. Generally, an increase in synthesis temperature resulted in structural transformations and the formation of more hydrated compounds. The metal complexes were characterized by elemental analysis, single-crystal and powder X-ray diffraction methods, thermal analysis (TG-DSC), ATR/FTIR, UV/Vis, and luminescence spectroscopy. The structural variety of three-dimensional coordination polymers can be ascribed to the temperature effect, which enforces the diversity of quinoline-2,4-dicarboxylate ligand denticity and conformation. The Qdca2− ligand only behaves as a bridging or bridging–chelating building block binding two to five metal centers with seven different coordination modes arising mainly from different carboxylate group coordination types. The presence of water molecules in the structures of complexes is crucial for their stability. The removal of both coordinated and non-coordinated water molecules leads to the disintegration and combustion of metal–organic frameworks to the appropriate lanthanide oxides. The luminescence features of complexes, quantum yield, and luminescent lifetimes were measured and analyzed. Only the Eu complexes show emission in the VIS region, whereas Nd and Er complexes emit in the NIR range. The luminescence properties of complexes were correlated with the crystal structures of the investigated complexes. [ABSTRACT FROM AUTHOR]

Complexes of lanthanide ions, such as Eu(III) (red light emission) and Tb(III) (green light emission), with proper ligands can be highly luminescent and color-tunable, also attaining yellow and orange emission under UV radiation. The ligands employed in this work were poly(sodium acrylate), working as polymeric matrix, and 1,10-phenanthroline, taking advantage of its antenna effect. Possibilities of color display were further enhanced by incorporating a cationic polyfluorene with blue emission. This strategy allowed for obtaining cyan and magenta, besides the aforementioned colors. Uncoated cellulose paper was impregnated with the resulting luminescent inks, observing a strong hypsochromic shift in excitation wavelength upon drying. Hence, while a cheap UV-A lamp sufficed to reveal the polyfluorene's blue emission, shorter wavelengths were necessary to visualize the emission due to lanthanide ions as well. The capacity to reveal, with UV-C radiation, a full-color image that remains invisible under natural light is undoubtedly useful for anti-counterfeiting applications. Furthermore, both lanthanide ion complexes and polyfluorenes were shown to have their luminescence quenched by Cu(II) ions and nitroarenes, respectively. [ABSTRACT FROM AUTHOR]

Lanthanide doped nanocrystalline fluoride optical materials have been explored for diverse applications in the solar energy harvesting, industry, medical, forensic and biological fields because of high photoluminescence quantum yield and low phonon energy. In this manuscript, Er3+/Yb3+:BaYF 5 nanocrystals were synthesized by hydrothermal process. These nanocrystals were investigated through X-ray diffraction (XRD), SEM/TEM, Raman, quantum yield, photoluminescence upconversion (UC) and downconversion (DC) studies. XRD patterns exhibited the cubic phase and no phase deviation with the addition of Er3+ and Yb3+ ions. The TEM images illustrate the cubic-like morphologies of the obtained nanocrystals. Raman spectrum unveils the characteristic vibrational bands with an intense band at 498 cm−1, which is considered the phonon energy of the BaYF 5 matrix. Under 488 nm excitation, the near infrared (NIR) emission of Er3+ increases up to 5 mol% and then decreases for a 10 mol% doped sample. Photoluminescence DC quantum yield of Er3+/Yb3+:BaYF 5 sample is measured by using integrating sphere in the visible region under 488 nm (Xe flash lamp) excitation, is 4.25%. Under 900 nm laser excitation, intense NIR emissions at 978 and 1550 nm corresponding to Yb3+ (2F 5/2 → 2F 7/2) and Er3+ (4I 13/2 → 4I 15/2) ions, respectively, were observed. With the increase of Yb3+ concentration, the NIR emissions of both Er3+ and Yb3+ increase to 5 mol% and then decrease to 10 mol%. The strength of green UC emission of Er3+ decreases with increase of Er3+ concentration, whereas it enhances with the rise of Yb3+ concentration under 980 nm laser excitation. Two-photon UC process is confirmed as the slopes of the green, and red intensities are 2 and 2. These nanocrystals exhibit intense UC and DC emissions under 980 nm and 480 nm, respectively, which can be suitable for improving the efficiency of solar cells. [ABSTRACT FROM AUTHOR]

To obtain optimal luminescence, 0.12 g of GdVO4:3%Eu3+ nanocrystals (NCs) and different volumes of nitrogen‐doped carbon dots (N‐CDs) crude solution were used as precursors, and the composite synthesized using the hydrothermal deposition method showed optimal luminescence when 11 ml (2.45 mmol) crude solution was used. In addition, similar composites with the same molar ratio as GVE/cCDs(11) were also prepared with the hydrothermal and physical mixing processes. Based on the test results of XRD, XPS, and PL spectra, for the composite GVE/cCDs(11), the highest (lowest) peak intensity of the C–C/C=C (C=O/C=N) bond, which was 1.18 (0.75) times that of GVE/cCDs‐m, indicated most N‐CDs deposition and led to their highest emission intensity under 365 nm excitation, although nitrogen atoms in the composite were shed slightly during the deposition process. Finally, as can be seen from the patterns designed for security applications that the optimally luminescent composite is one of the most promising candidates in the anti‐counterfeiting field. [ABSTRACT FROM AUTHOR]

In this work, we have compiled our research on lanthanide-based luminescent materials for use as down-shifter layers in photovoltaic (PV) mini-modules. The complexes we have prepared (C1–17), with formulas [Eu2(phen)2(bz)6] (C1), [Eu2(bphen)2(bz)6] (C2), [Eu(tta)3bphen] (C3), [Eu(bta)3pyz-phen] (C4), [Eu(tta)3pyz-phen] (C5), [Eu(bta)3me-phen] (C6), [Er(bta)3me-phen] (C7), [Yb(bta)3me-phen] (C8), [Gd(bta)3me-phen] (C9), [Yb(bta)3pyz-phen] (C10), [Er(tta)3pyz-phen] (C11), [Eu2(bz)4(tta)2(phen)2] (C12), [Gd2(bz)4(tta)2(phen)2] (C13), [EuTb(bz)4(tta)2(phen)2] (C14), [EuGd(bz)4(tta)2(phen)2] (C15), [Eu1.2Gd0.8(bz)4(tta)2(phen)2] (C16), and [Eu1.6Gd0.4(bz)4(tta)2(phen)2] (C17), can be grouped into three families based on their composition: Complexes C1–6 were synthesized using Eu3+ ions and phenanthroline derivatives as the neutral ligands and fluorinated β-diketonates as the anionic ligands. Complexes C7–11 were prepared with ligands similar to those of complexes C1–6 but were synthesized with Er3+, Yb3+, or Gd3+ ions. Complexes C12–17 have the general formula [M1M2(bz)4(tta)2(phen)2], where M1 and M2 can be Eu3+, Gd3+, or Tb3+ ions, and the ligands were benzoate (bz–), 2-thenoyltrifluoroacetone (tta–), and 1,10–phenanthroline (phen). Most of the complexes were characterized using X-ray techniques, and their photoluminescent properties were studied. We then assessed the impact of complexes in the C1–6 and C12–17 series on the EQE of PV mini-modules and examined the durability of one of the complexes (C6) in a climate chamber when embedded in PMMA and EVA films. This study emphasizes the methodology employed and the key findings, including enhanced mini-module efficiency. Additionally, we present promising results on the application of complex C6 in a bifacial solar cell. [ABSTRACT FROM AUTHOR]

We obtained thorough insight into the capabilities of various computational methods to account for the ligand field (LF) regime in lanthanide compounds, namely, a weakly perturbed ionic body and quasidegenerate orbital multiplets. The LF version of the angular overlap model (AOM) was considered. We intentionally took very simple idealized systems, the hypothetical [TbF]2+, [TbF2]+ and [Tb(O2NO)]2+, in order to explore the details overlooked in applications on complex realistic systems. We examined the 4f and 5d orbital functions in connection to f–f and f–d transitions in the frame of the two large classes of quantum chemical methods: wave function theory (WFT) and density functional theory (DFT). WFT methods are better suited to the LF paradigm. In lanthanide compounds, DFT faces intrinsic limitations because of the frequent occurrence of quasidegenerate ground states. Such difficulties can be partly encompassed by the nonstandard control of orbital occupation schemes. Surprisingly, we found that the simplest crystal field electrostatic approximation, reconsidered with modern basis sets, works well for LF parameters in ionic lanthanide systems. We debated the largely overlooked holohedrization effect that inserts artificial inversion symmetry into standard LF Hamiltonians. [ABSTRACT FROM AUTHOR]

Lanthanide coordinating polymeric microparticles have witnessed increasing research interests during the past decades due to their versatile morphology and tunable fluorescent properties. Herein, we have synthesized an amidoximed block copolymer containing aromatic backbone and pendent amidoxime as well as carboxyl groups, which has been employed as the ligand to sensitize the intrinsic fluorescence emission of lanthanide ions of Tb3+ and Eu3+. Furthermore, the lanthanide coordinating polymeric microparticles showing tunable green and red emission fluorescence have been prepared via the emulsion confinement co-self-assembly of amidoximed polymeric ligands with Tb3+ and Eu3+. It is found that both the fluorescence emission and sizes of obtained fluorescent microparticles can be easily modulated in a wide range by tuning concentration of polymers and lanthanide ions, as well as emulsion evaporation temperature. Thanks to their tunable sizes (250–900 nm), fluorescence emission as well as presence of surface active functional groups, the present fluorescent microparticles would find potential applications in in-vitro detection, optical encoding and devices.

Wide‐coverage near infrared (NIR) phosphor‐converted LEDs possess promising potential for practical applications, but little is developed towards the efficient and wide‐coverage NIR phosphors. Here, we report the single‐component lanthanide (Ln3+) ions doped Cs2M(In0.95Sb0.05)Cl6 (M=alkali metal) nanocrystals (NCs), exhibiting emission from 850 to 1650 nm with high photoluminescence quantum yield of 20.3 %, which is accomplished by shaping the multiple metal halide octahedra of double perovskite via the simple alkali metal substitution. From Judd‐Ofelt theoretical calculation and spectroscopic investigations, the shaping of metal halide octahedra in Cs2M(In1−xSbx)Cl6 NCs can break the forbidden of f‐f transition of Ln3+, thus increasing their radiative transition rates and simultaneously boosting the energy transfer efficiency from host to Ln3+. Finally, the wide‐coverage NIR LEDs based on Sm3+, Nd3+, Er3+‐tridoped Cs2K0.5Rb0.5(In0.95Sb0.05)Cl6 NCs are fabricated and employed in the multiplex gas sensing and night‐vision application. [ABSTRACT FROM AUTHOR]

This paper contains the design of active optical lenses used for the detection of arc flashing emissions. The phenomenon of an arc flashing emission and its characteristics were contemplated. Methods of preventing these emissions in electric power systems were discussed as well. The article also includes a comparison of commercially available detectors. An analysis of the material properties of fluorescent optical fiber UV-VIS-detecting sensors constitutes a major part of the paper. The main purpose of the work was to make an active lens using photoluminescent materials, which can convert ultraviolet radiation into visible light. As part of the work, active lenses with materials such as Poly(methyl 2-methylpropenoate) (PMMA) and phosphate glass doped with lanthanides, such as terbium (Tb3+) and europium (Eu3+) ions, were analyzed. These lenses were used to make optical sensors, which were supported by commercially available sensors in their construction. [ABSTRACT FROM AUTHOR]

Luminescent nanothermometry can precisely and remotely measure the internal temperature of objects at nanoscale precision, which, therefore, has been placed at the forefront of scientific attention. In particular, due to the high photochemical stability, low toxicity, rich working mechanisms, and superior thermometric performance, lanthanide-based ratiometric luminesencent thermometers are finding prevalent uses in integrated electronics and optoelectronics, property analysis of in-situ tracking, biomedical diagnosis and therapy, and wearable e-health monitoring. Despite recent progresses, it remains debate in terms of the underlying temperature-sensing mechanisms, the quantitative characterization of performance, and the reliability of temperature readouts. In this review, we show the origin of thermal response luminescence, rationalize the ratiometric scheme or thermometric mechanisms, delve into the problems in the characterization of thermometric performance, discuss the universal rules for the quantitative comparison, and showcase the cutting-edge design and emerging applications of lanthanide-based ratiometric thermometers. Finally, we cast a look at the challenges and emerging opportunities for further advances in this field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Room-temperature synthesis of COF materials enriched with anchoring sites. • The spherical COF probe has superior performance of dispersion. • Pore restriction and antenna effect facilitate the selective recognition. • COF-Eu shows excellent performance of recovery and detection for Flumequine. The overuse of quinolone antibiotics has led to a series of health and environmental issues. Herein, we combine the distinct luminescence properties of Eu3+ with the unique structure of covalent organic frameworks (COFs) to develop a precise and sensitive fluorescent probe for detecting Flumequine (Flu) in water. Eu3+ is thoroughly anchored into the channels of COFs as recognition sites, while the synthesized probe material still maintains its intact framework structure. The unique structure of COFs provides excellent support and protection for Eu3+. Therefore, COF-Eu can rapidly bind with Flu which can transfer the absorbed energy to Eu3+ through an "antenna effect", resulting in red fluorescence. Moreover, there is a good linear relationship between Flu concentration in the range of 0–30 µM, with a detection limit of 41 nM. Simultaneously, the material maintains remarkable reproducibility, with its performance remaining almost unchanged after five cycles of use. Remarkably, the probe demonstrates excellent Flu recovery rates in real samples. This study provides a viable approach for the recognition of flumequine in the environment through a customized fluorescence detection method. [ABSTRACT FROM AUTHOR]

Luminescence thermometry, leveraging the temperature-dependent luminescent properties of coordination compounds, offers precise and remote temperature measurement. However, many existing luminescent thermometers exhibit a narrow peak in temperature sensitivity, restricting their effective operating range. In this study, we synthesized new complexes [LnL 2 (NO 3)(TPPO) 2 ], where Ln = Eu (1), Tb (2), Gd (3), Tb 0.94 Eu 0.06 (4), (HL - 4,4,4-trifluoro-1-(furan-2-yl) butan-1,3-dione, TPPO - triphenylphosphine oxide, which demonstrate an exceptionally wide and stable range of maximum temperature sensitivity of 3 %×K−1, spanning from 180 to 320 K. Furthermore, the temperature uncertainty remained low and stable across the same temperature region, ensuring reliable measurements. An unusual behavior was observed in the ion-to-ion energy transfer process rate constant, which exhibited an additional peak between 120 and 180 K. This phenomenon warrants further investigation to fully understand the underlying mechanisms. The obtained results allow for creation of new highly efficient luminescent thermometers tailored for specific complex applications, including cryobiology and microfluidics. [Display omitted] • Novel mixed Eu/Tb 1,3-diketonates were proposed for luminescence thermometry. • Stable thermal sensitivity S r of 3 %×K −1 was observed from 180 to 320 K. • Mixed-metal complex shows temperature uncertainty less than <1 K from 170 to 330 K. • Energy transfer process rate constant exhibited an unusual peak from 120 to 180 K. [ABSTRACT FROM AUTHOR]

Quick screening and in-situ detection of trace antibiotics in environmental samples is needed for better control and monitoring of antibiotics pollution. Herein, a novel dual-lanthanide (Tb3+ and Eu3+) cyclodextrin-polyoxometalate fluorescent assembly (CD-LnPOM) has been developed for ciprofloxacin (CIP) detection. The "ratiometric" fluorescence response of CD-LnPOM enables specific detection of CIP within 5 s over a wide concentration range (0–100 μM) with a detection limit of 0.266 nM. When CIP presents, cyclodextrin acts as a host and encapsulates CIP in the cavity through host-guest interaction, which enhances the antenna sensitization between Tb3+ and CIP. Meanwhile, due to the more robust coordination between CIP and Tb3+, CIP blocks the energy transfer from Tb3+ to Eu3+ and recovers the sensitization of Tb3+ by POM. Based on the developed CD-LnPOM probe, a portable sensing device based on digital image color analysis is successfully demonstrated for real river water and antibiotic sludge samples. The developed fluorescent probe enables rapid and in-situ detection of trace antibiotics, which offers a new method for antibiotics screening and monitoring. [Display omitted] • Ciprofloxacin detection within 5 s with a detection limit of 0.266 nM. • Dual-lanthanide cyclodextrin-polyoxometalate fluorescent probe. • Portable instrument with fluorescent color change for in-situ detection of antibiotics. • Antibiotics detection in river water and antibiotic sludge samples. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln)-doped upconverting nanocrystals (LnNPs) exhibit suitable features as energy donors for Förster resonance energy transfer (FRET). The sensitivity of biosensors can be improved by optically active materials with anti-Stokes emission, narrowband absorption and emission spectral lines, and long luminescence lifetimes. In contrast to energy reabsorption, energy transfer between the upconversion nanocrystals (UCNPs) and organic dyes attached to their surface can be observed through donor emission quenching and acceptor emission and decreases in the luminescence lifetimes of donors. Although the emission spectra confirmed that FRET occurred from the Er3+ ions to the Rose Bengal acceptor, the luminescence lifetimes were generally not affected by the presence of the acceptor. The Ln3+ dopant in LnNPs, which typically has 20–100 % Yb3+ sensitizer ions and 0.2–2% activator (Er3+/Tm3+/Ho3+) ions, results in hundreds to thousands of Ln3+ ions in a single UCNP. The interaction between multiple Ln3+ ions results in significant energy migration and storage in the Yb3+ sensitizer network, which is often recharged with the energy of the Er3+ ions when they emit and nonradiatively transfer their energy to acceptor species. However, the energy transfer mechanisms could not be unambiguously determined through spectroscopic data due to the nature the upconversion process. Studies confirmed that the energy migration distance was significantly shortened when the LnNP surface contained acceptors; this affected the energy storage and 'recharging' capability of the Yb3+ sensitizer network within the UCNPs. These results provide hints on the future use of LnNP as effective FRET probes, in which the highest possible absorption cross section and possibly lowest dopant concentration should be maintained. [Display omitted] • Based on the Monte Carlo model, a shorter total energy migration distance was observed for the NPs with attached dye. • The effect of energy migration between the Ln3+ on the efficiency of FRET was verified with a Monte Carlo algorithm. • The effect of energy migration between the Ln3+ on the efficiency of FRET was experimentally verified spectroscopically. • Experimentally measured luminescence lifetimes, provided analogous theoretical trends for the total distance traveled. • Experimentally measured rise luminescence lifetimes changed similarly to the FRET efficiencies obtained from emission spectra. [ABSTRACT FROM AUTHOR]

Chemiluminescence (CL) methods, based on redox reactions are of substantial importance in analytical chemistry. The occurrence of chemiluminescence, requires liberation of a sufficient portion of energy in a single elementary stage of the reaction, the presence of molecules capable of accumulation of energy from the chemical reaction in the form of electronic excitation and showing the highest possible luminescence and excitation yields. It is still a major challenge to get chemiluminescence of sufficiently high emission intensity. The efforts to improve the analytical parameters of methods based on chemiluminescence focus on the search for substances that would increase the emission, sensitivity and selectivity of these methods. This review paper sums up the hitherto advances in the studies of chemiluminescence enhancing substances, starting from classical dyes, organic low-molecular weight compounds, lanthanide ions to nanoparticles in systems with different oxidizers. These substances take part in reactions as CL emitters, energy acceptors, catalysts and reagents. In this article, for particular types of CL-enhancers, the mechanisms of CL enhancement and analytical applications of the reaction mixtures are described, together with comments on future challenges and perspectives in this area. • Mechanisms of enhanced chemiluminescence. • Organic enhancers: classical dyes, low-molecular weight organic compounds. • Inorganic enhancers: lanthanide ions, nanoparticles. • Analytical applications of enhanced chemiluminescence. [ABSTRACT FROM AUTHOR]

Abstract Perovskite nanocrystals (NCs) with intentionally introduced Mn2+/Yb3+ activators enable tunable emissions covering UV‐orange‐NIR spectral range. However, the exact microscopic energy transfer mechanisms in this system remain unknown. Herein, Mn/Yb codoped CsPbCl3 perovskite NCs with triple emissions originated from exciton recombination of host, 3d–3d transition of Mn2+ and 4f–4f transition of Yb3+ are prepared. Femtosecond resolution transient absorption spectra performed on the pristine CsPbCl3, Mn‐doped, Yb‐doped and Mn/Yb codoped samples clarify efficient and simultaneous energy transfer (ET) from excitons to Mn2+ and Yb3+ dopants. It is testified the sensitizations of dopants mainly result from the trapped hole, taking 285 ps for Mn2+ and 17 ps for Yb3+ respectively, which make less trapped hole recombine with de‐localized carriers. Importantly, energy transfer processes from host to Mn2+ and Yb3+ activators emerge as competition, and the ET probability of exciton‐to‐Mn2+ is higher than that of exciton‐to‐Yb3+. Finally, control experiments further prove that tunable Mn2+ orange emission and Yb3+ NIR emission are achievable via elaborate adjustment of the dopant concentrations.