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Lanthanide (Ln3+) oxysulfide nanocrystals (NCs) have great prospect in many advanced technologies; however, they suffer from a low photoluminescence efficiency due to the volatility of sulfur and deleterious surface quenching effect. Herein, we report a novel sandwiched luminescent heterostructure based on Ln3+‐doped Gd2O2S@NaYF4 core/shell NCs with tunable sulfur content in the sandwich layer. By means of Eu3+ as the sensitive structural probes, we unravel the ligand‐mediated structure control of the NCs from Gd2O3: Ln3+@NaYF4 to Gd2O2S: Ln3+@NaYF4 with tailored S2– deficiency. Such a sandwich‐type core/shell heterostructure enables us to achieve efficient and multicolor downshifting and upconversion luminescence (UCL), with up to 208.8 folds of enhancement in UCL intensity as compared to that of their core‐only counterparts. These findings provide a general approach for the controlled synthesis of lanthanide oxysulfide@fluoride heterostructure, which offers a new way for the materials design towards diverse emerging applications. [ABSTRACT FROM AUTHOR]

Hybrid composites made of metal-organic frameworks (MOFs) and lanthanide-doped upconversion nanoparticles (UCNPs) have attracted considerable interest for their synergistically enhanced functions in various applications such as chemical sensing, photocatalysis, anticounterfeiting and nanomedicine. However, precise assembly of MOF/UCNP hybrid composites with tunable morphologies remains a challenge due to the lack of effective synthetic methods and fundamental understanding of the growth mechanisms. Herein, we propose a modulator-directed assembly strategy to synthesize a series of ZIF-8@UCNP composites (ZIF-8 = zeolitic imidazolate framework-8). The UCNPs densely paved on the surface of ZIF-8 microcrystals and endowed the composites with intense upconversion blue emission, which were verified by steady-state/transient photoluminescence (PL) spectroscopy and single-particle imaging. Ethylenediamine (EDA) was firstly used as a modulator to fine-tune the predominant MOF facets and realized distinct morphologies of the composites. By adjusting the concentration of EDA from 0 to 25 mmol/L, the morphology of the ZIF-8@UCNP composites was tuned from rhombic dodecahedron (RD) to truncated rhombic dodecahedron (TRD), cube with truncated edges (CTE), cube, and finally a unique form of interpenetration twins (IT). The nucleation and growth process of the ZIF-8@UCNP composites was monitored by time-dependent scanning electron microscopy (SEM) images and the formation mechanism was thoroughly revealed. Furthermore, we demonstrated that the strategy for assembly of morphology-controllable ZIF-8@UCNP composites was generally applicable to various UCNPs with different sizes and shapes. The proposed strategy is expected to open up new avenues for the controllable synthesis of MOF/UCNP composites toward diverse applications. [ABSTRACT FROM AUTHOR]

Currently, lanthanide (Ln3+)‐doped near‐infrared (NIR)‐emitting double perovskites (DPs) suffer from low photoluminescence quantum yield (PLQY). Herein, we develop a new class of NIR‐emitting DPs based on Ln3+‐doped Cs2(Na/Ag)BiCl6. Benefiting from the Na+‐induced breakdown of local site symmetry in the Cs2AgBiCl6 DPs, effective NIR emissions of Ln3+ are realized through Bi3+ sensitization. Specifically, 7.3‐fold and 362.9‐fold enhanced NIR emissions of Yb3+ and Er3+ are achieved in Cs2Ag0.2Na0.8BiCl6 DPs relative to those in Na‐free Cs2AgBiCl6 counterparts, respectively. The optimal absolute NIR PLQYs for Yb3+ and Er3+ in Cs2Ag0.2Na0.8BiCl6 DPs are determined to be 19.0 % and 4.3 %, respectively. Raman spectroscopy and first‐principles density functional theory calculations verify the sublattice distortion in Cs2(Na/Ag)BiCl6 DPs via Na+ doping. These findings provide fundamental insights into the design of efficient NIR‐emitting Ln3+‐doped DPs for versatile optoelectronic applications. [ABSTRACT FROM AUTHOR]

All‐inorganic lead‐free perovskite‐derivative metal halides have shown great promise in optoelectronics, however, it remains challenging to realize efficient near‐infrared (NIR) luminescence in these materials. Herein, we report a novel strategy based on Te4+/Ln3+ (Ln=Er, Nd, and Yb) co‐doping to achieve efficient NIR luminescence in vacancy‐ordered double perovskite Cs2ZrCl6 phosphors, which are excitable by a low‐cost near‐ultraviolet light‐emitting diode (LED) chip. Through sensitization by the spin‐orbital allowed 1S0→3P1 transition of Te4+, intense and multi‐wavelength NIR luminescence originating from the 4f→4f transitions of Er3+, Nd3+, and Yb3+ was acquired, with a quantum yield of 6.1 % for the Er3+ emission. These findings provide a general approach to achieve efficient NIR emission in lead‐free metal halides through ns2‐metal and lanthanide ion co‐doping, thereby opening up a new avenue for exploring NIR‐emitting perovskite derivatives towards versatile applications such as NIR‐LEDs and bioimaging. [ABSTRACT FROM AUTHOR]

Rare earth (RE3+)-doped phosphors generally suffer from thermal quenching, in which their photoluminescence (PL) intensities decrease at high temperatures. Herein, we report a class of unique two-dimensional negative-thermal-expansion phosphor of Sc2(MoO4)3:Yb/Er. By virtue of the reduced distances between sensitizers and emitters as well as confined energy migration with increasing the temperature, a 45-fold enhancement of green upconversion (UC) luminescence and a 450-fold enhancement of near-infrared downshifting (DS) luminescence of Er3+ are achieved upon raising the temperature from 298 to 773 K. The thermally boosted UC and DS luminescence mechanism is systematically investigated through in situ temperature-dependent Raman spectroscopy, synchrotron X-ray diffraction and PL dynamics. Moreover, the luminescence lifetime of 4I13/2 of Er3+ in Sc2(MoO4)3:Yb/Er displays a strong temperature dependence, enabling luminescence thermometry with the highest relative sensitivity of 12.3%/K at 298 K and low temperature uncertainty of 0.11 K at 623 K. These findings may gain a vital insight into the design of negative-thermal-expansion RE3+-doped phosphors for versatile applications. Rare-earth doped phosphors with negative thermal expansion (NTE) may display thermally-enhanced emission, but their performance is generally limited. Here the authors report thermally-boosted green upconversion luminescence and near-infrared downshifting luminescence in Sc2(MoO4)3:Yb/Er phosphors with two-dimensional NTE, and their application in temperature sensing. [ABSTRACT FROM AUTHOR]

The point‐of‐care detection of tumor markers in saliva with high sensitivity and specificity remains a daunting challenge in biomedical research and clinical applications. Herein, a facile and ultrasensitive detection of tumor marker in saliva based on luminescence‐amplification strategy of lanthanide nanoprobes is proposed. Eu2O3 nanocrystals are employed as bioprobes, which can be easily dissolved in acidic enhancer solution and transform into a large number of highly luminescent Eu3+ micelles. Meanwhile, disposable syringe filter equipped with nitrocellulose membrane is used as bioassay platform, which facilitates the accomplishment of detection process within 10 min. The rational integration of dissolution enhanced luminescent bioassay strategy and miniaturized detection device enables the unique lab‐in‐syringe assay of tumor marker like carcinoembryonic antigen (CEA, an important tumor marker in clinic diagnosis and prognosis of cancer) with a detection limit down to 1.47 pg mL−1 (7.35 × 10−15m). Upon illumination with a portable UV flashlight, the photoluminescence intensity change above 0.1 ng mL−1 (0.5 × 10−12m) of CEA can be visually detected by naked eyes, which allows one to qualitatively evaluate the CEA level. Moreover, we confirm the reliability of using the amplified luminescence of Eu2O3 nanoprobes for direct quantitation of CEA in patient saliva samples, thus validates the practicality of the proposed strategy for both clinical diagnosis and home self‐monitoring of tumor marker in human saliva. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln3+)-doped upconversion nanoparticles (UCNPs), exhibiting excellent optical properties such as long photoluminescence lifetime, narrow emission bandwidth, and low autofluorescence background, have been applied in many fields, especially in biological analysis and medical diagnostics. Despite the exciting progress, the applications of Ln3+-doped UCNPs are hindered by the small absorption cross-section and low upconversion luminescence efficiency of Ln3+. To this regard, several effective strategies associated with energy transfer designing have been proposed to modulate the upconversion luminescence properties of Ln3+ in the past few decades. In this feature article, we focus on the most recent development of optical property designing in Ln3+-doped UCNPs on the basis of energy transfer between Ln3+–Ln3+, Ln3+–dyes, and Ln3+–quantum dots. Some future efforts towards the energy transfer designing in Ln3+-doped UCNPs are also proposed. [ABSTRACT FROM AUTHOR]

The detection of circulating tumor cells (CTCs) is crucial to early cancer diagnosis and the evaluation of cancer metastasis. However, it remains challenging due to the scarcity of CTCs in the blood. Herein, we report an ultrasensitive platform for the direct detection of CTCs using luminescent lanthanide nanoprobes. These were designed to recognize the epithelial cell adhesion molecules on cancer cells, allowing signal amplification through dissolution‐enhanced time‐resolved photoluminescence (TRPL) and the elimination of short‐lived autofluorescence interference. This enabled the direct detection of blood breast‐cancer cells with a limit of detection down to 1 cell/well of a 96‐well plate. Moreover, blood CTCs (≥10 cells mL−1) can be detected in cancer patients with a detection rate of 93.9 % (14/15 patients). We envision that this ultrasensitive detection platform with excellent practicality may provide an effective strategy for early cancer diagnosis and prognosis evaluation. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln3+)‐doped luminescent nanoparticles (NPs) with emission in the second near‐infrared (NIR‐II) biological window have shown great promise but their applications are currently limited by the low absorption efficiency of Ln3+ owing to the parity‐forbidden 4f→4f electronic transition. Herein, we developed a strategy for the controlled synthesis of a new class of NIR‐II luminescent nanoprobes based on Ce3+/Er3+ and Ce3+/Nd3+ co‐doped CaS NPs, which can be effectively excited by using a low‐cost blue light‐emitting diode chip. Through sensitization by the allowed 4f→5d transition of Ce3+, intense NIR‐II luminescence from Er3+ and Nd3+ with quantum yields of 9.3 % and 7.7 % was achieved, respectively. By coating them with a layer of amphiphilic phospholipids, these NPs exhibit excellent stability in water and can be exploited as sensitive NIR‐II luminescent nanoprobes for the accurate detection of an important disease biomarker, xanthine, with a detection limit of 32.0 nm. [ABSTRACT FROM AUTHOR]

Lanthanide-doped upconversion nanoparticles (UCNPs) have shown great promise in versatile bioapplications. For the first time, organosilica-shelled β-NaLuF4:Gd/Yb/Er nanoprobes with a rattle structure have been designed for dual-modal imaging and photodynamic therapy (PDT). Benefiting from the unique rattle structure and aromatic framework, these nanoprobes are endowed with a high loading capacity and the disaggregation effect of photosensitizers. After loading of β-carboxyphthalocyanine zinc or rose Bengal into the nanoprobes, we achieved higher energy transfer efficiency from UCNPs to photosensitizers as compared to those with conventional core-shell structure or with pure-silica shell, which facilitates a large production of singlet oxygen and thus an enhanced PDT efficacy. We demonstrated the use of these nanoprobes in proof-of-concept X-ray computed tomography (CT) and UC imaging, thus revealing the great potential of this multifunctional material as an excellent nanoplatform for cancer theranostics. [ABSTRACT FROM AUTHOR]

Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted considerable interest due to their superior physicochemical features, such as large anti-Stokes shifts, low autofluorescence background, low toxicity and high penetration depth, which make them extremely suitable for use as alternatives to conventional downshifting luminescence bioprobes like organic dyes and quantum dots for various biological applications. A fundamental understanding of the photophysics of lanthanide-doped UCNPs is of vital importance for discovering novel optical properties and exploring their new applications. In this review, we focus on the most recent advances in the development of lanthanide-doped UCNPs as potential luminescent nano-bioprobes by means of our customized lanthanide photophysics measurement platforms specially designed for upconversion luminescence, which covers from their fundamental photophysics to bioapplications, including electronic structures (energy levels and local site symmetry of emitters), excited-state dynamics, optical property designing, and their promising applications for in vitro biodetection of tumor markers. Some future prospects and efforts towards this rapidly growing field are also envisioned. [ABSTRACT FROM AUTHOR]

Time-resolved (TR) photoluminescence (PL) biosensing has been widely adopted in many research and medical institutions. However, commercial molecular TRPL bioprobes like lanthanide (Ln3+)-chelates suffer from poor photochemical stability and long-term toxicity. Inorganic Ln3+-doped nanocrystals (NCs), owing to their superior physicochemical properties over Ln3+-chelates, are regarded as a new generation of luminescent nanoprobes for TRPL biosensing. The long-lived PL of Ln3+-doped NCs combined with the TRPL technique is able to completely suppress the interference of the short-lived background, resulting in a background-free signal and therefore a remarkable sensitivity for biosensing. In this feature article, we summarize the latest advancements in inorganic Ln3+-doped NCs as TRPL nano-bioprobes from their fundamental optical properties to their potential applications for ultrasensitive biodetection and high-resolution bioimaging. Future efforts towards the commercialization of these nanoprobes are also proposed. [ABSTRACT FROM AUTHOR]

Lanthanide-doped upconversion nanoparticles (UCNPs) have shown great promise in bioapplications. Exploring new host materials to realize efficient upconversion luminescence (UCL) output is a goal of general concern. Herein, we develop a unique strategy for the synthesis of novel LiLuF4:Ln3+ core/shell UCNPs with typically high absolute upconversion quantum yields of 5.0 % and 7.6 % for Er3+ and Tm3+, respectively. Based on our customized UCL biodetection system, we demonstrate for the first time the application of LiLuF4:Ln3+ core/shell UCNPs as sensitive UCL bioprobes for the detection of an important disease marker β subunit of human chorionic gonadotropin (β-hCG) with a detection limit of 3.8 ng mL−1, which is comparable to the β-hCG level in the serum of normal humans. Furthermore, we use these UCNPs in proof-of-concept computed tomography imaging and UCL imaging of cancer cells, thus revealing the great potential of LiLuF4:Ln3+ UCNPs as efficient nano-bioprobes in disease diagnosis. [ABSTRACT FROM AUTHOR]

Lanthanide-doped inorganic nanoparticles possess superior physicochemical features such as long-lived luminescence, large antenna-generated Stokes or anti-Stokes shifts, narrow emission bands, high resistance to photobleaching and low toxicity, and thus are regarded as a new generation of luminescent bioprobes as compared to conventional molecular probes like organic dyes and lanthanide chelates. These functional nanoparticles, although most of their bulk counterparts were well studied previously, have attracted renewed interest for their biomedical applications in areas as diverse as biodetection, bioimaging, and disease diagnosis and therapeutics. In this review, we provide a comprehensive survey of the latest advances made in developing lanthanide-doped inorganic nanoparticles as potential luminescent bioprobes, which covers areas from their fundamental chemical and physical features to bioapplications including controlled synthesis methodology, surface modification chemistry, optical spectroscopy, and their promising applications in diverse fields, with an emphasis on heterogeneous and homogeneous in vitro biodetection of tumor markers and multimodal bioimaging of various tumor tissues. Some future prospects and challenges in this rapidly growing field are also summarized. [ABSTRACT FROM AUTHOR]

Photon upconversion is promising for applications such as biological imaging, data storage or solar cells. Here, we have investigated upconversion processes in a broad range of gadolinium-based nanoparticles of varying composition. We show that by rational design of a core-shell structure with a set of lanthanide ions incorporated into separated layers at precisely defined concentrations, efficient upconversion emission can be realized through gadolinium sublattice-mediated energy migration for a wide range of lanthanide activators without long-lived intermediary energy states. Furthermore, the use of the core-shell structure allows the elimination of deleterious cross-relaxation. This effect enables fine-tuning of upconversion emission through trapping of the migrating energy by the activators. Indeed, the findings described here suggest a general approach to constructing a new class of luminescent materials with tunable upconversion emissions by controlled manipulation of energy transfer within a nanoscopic region. [ABSTRACT FROM AUTHOR]

Sm3+ and Dy3+ ions doped hexagonal wurtzite ZnO nanocrystals were fabricated by a sol-gel method. The obtained ZnO nanocrystals were characterized using the X-ray diffraction, transmission electron microscopy, ultraviolet-visible reflectance spectra, and low-temperature luminescence spectroscopy. Intense and well resolved emission lines for Sm3+ and Dy3+ ions can be achieved via an energy transfer process from ZnO host to the dopants. It was found that the host sensitized emissions were more efficient than that of direct excitation for Sm3+ and Dy3+ ions. Moreover, multiple sites of Sm3+ and Dy3+ ions in ZnO nanocrystals were identified based on the low-temperature photoluminescence spectra. [ABSTRACT FROM AUTHOR]

In dieser Replik entgegnen die Autoren der Zuschrift „Breakdown of Crystallographic Site Symmetry in Lanthanide ‐ Doped NaYF4 Crystals“ dem Kommentar von Karbowiak et al., welche die Kristallfeldanalyse des Eu3+ ‐ Ions in ungeordnetem NaYF4 kritisierten. Die Autoren stellen klar, dass die Kritik auf mehreren Missverständnissen beruht. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new class of NIR-LED photostimulated luminescence (PSL) nanoprobes based on SrS:Eu2+,Dy3+@SrS NCs is proposed. • The stimulation band of these SrS:Eu2+,Dy3+@SrS NCs spans from 700 to 1400 nm. • A PSL duration time longer than 2 h is achieved upon 808-nm LED stimulation. • These SrS:Eu2+,Dy3+@SrS nanoprobes are exploited for tumor-targeted imaging in zebrafish. Near-infrared (NIR) photostimulated luminescence (PSL) nanocrystals (NCs) exhibit deep penetrability and low autofluorescence, recently evoking extensive interest for their application in biosensing. Nevertheless, most of the NIR PSL NCs encounter substantial constraints in biomedicine applications, primarily stemming from the necessity of high-power diode laser stimulation or their larger particle size. Herein, we design a new class of NIR light-emitting diode (LED) PSL NCs based on SrS:Eu2+ NCs, which were coated with SrS shell to improve their stability and photoluminescence (PL) intensity. The trap depth and density of the NCs were further tailored through thermal annealing and Dy3+ co-doping, resulting in efficient NIR PSL with a duration time longer than 2 h by stimulation with an NIR LED in a broad region within 700–1400 nm. Benefiting from their excellent NIR PSL, we showcased the potential of SrS:Eu2+,Dy3+@SrS NCs as sensitive nanoprobes for tumor-targeted imaging in zebrafish with a signal-to-noise ratio of 18.9. These findings demonstrate the significant promise of the proposed SrS:Eu2+,Dy3+@SrS nanoprobes for in vivo bioimaging, which may pave the way for the development of effective NIR PSL nanoprobes for diverse bioapplications in the future. [ABSTRACT FROM AUTHOR]

Highlights • The fundamental photophysics of Eu3+-activated luminescent nanoprobes are overviewed. • The strategies for enhancing the downshifting/upconverting luminescence of Eu3+-activated nanoprobes are summarized. • Heterogeneous and homogeneous biodetections based on Eu3+-activated luminescent nanoprobes are exemplified. • In vitro and in vivo bioimagings based on Eu3+-activated luminescent nanoprobes are specifically outlined. Abstract Trivalent europium ions (Eu3+) activated inorganic materials, known as one of the most important red-emitting phosphors, are emerging as an attractive class of luminescent materials over the past decades. Specifically, Eu3+ ion is considered as an ideal spectroscopic probe to decipher the local environment in view of its non-degenerate ground state of 7F 0 and excitation state of 5D 0. Benefiting from the intense long-lived luminescence from 5D 0 , Eu3+-activated inorganic nanoparticles are also frequently reported as luminescent probes in biological assays and medical imaging. With the development of advanced synthesis strategies and characterization techniques, more new understanding or progress in Eu3+-activated luminescent nanoprobes have been gained with regard to their fundamental photophysics/photochemistry properties and versatile bioapplications. As such, it is urgent to renew the knowledge in this field. Rather than being exhaustive, this review aims to highlight the latest progress in the electronic structures, optical properties and emerging bioapplications of Eu3+-activated nanoprobes, which covers from spectroscopic site symmetry, excited-state dynamics, downshifting/upconversion luminescence enhancement strategies, and luminescent biosensing, with an emphasis on their heterogeneous/homogeneous biodetection as well as in vitro and in vivo bioimaging. Some future prospects and efforts toward this rapidly developing field are also discussed. [ABSTRACT FROM AUTHOR]

Lanthanide ions (Ln 3+ ) doped disordered crystals, which exhibit excellent downshifting/upconversion luminescent properties, are widely used in a variety of optical and optoelectronic fields. The optical properties of Ln 3+ ions are critically dependent on the local structure around Ln 3+ ions. Therefore, by employing Ln 3+ ( e.g. , Eu 3+ ) as the sensitive structural probe, the local structure and site symmetry of Ln 3+ dopants in the disordered crystals can be determined. Furthermore, through modification of the local site symmetry of Ln 3+ ions, various highly efficient Ln 3+ -doped luminescent materials have been designed over the past decade. As such, it is urgent to renew the knowledge about the huge family of Ln 3+ -doped disordered crystals. Rather than being exhaustive, this review aims to highlight the most recent advances in the site symmetry and optical properties of Ln 3+ -doped disordered crystals, with an emphasis on probing the local site symmetry and tuning downshifting/upconversion luminescent properties based on modification of the microstructures around Ln 3+ dopants. Finally, the challenges and future perspectives of this important kind of phosphors are proposed. [ABSTRACT FROM AUTHOR]

The abnormal Fe3+ level is known to cause various diseases, such as heart failure, liver damage and neurodegeneration. In situ probing Fe3+ in living cells or organisms is highly desired for both biological research and medical diagnostics. Herein, hybrid nanocomposites NaEuF 4 @TCPP were constructed by the assembly of an aggregation-induced emission luminogen (AIEgen) TCPP and NaEuF 4 nanocrystals (NCs). The anchored TCPP on the surface of NaEuF 4 NCs can reduce rotational relaxation of the excited state and efficiently transfer the energy to the Eu3+ ions with minimized nonradiative energy loss. Consequently, the prepared NaEuF 4 @TCPP nanoparticles (NPs) exhibited an intense red emission with a 103-fold enhancement relative to that in NaEuF 4 NCs under 365 nm excitation. A selectively quenching response to Fe3+ ions for the NaEuF 4 @TCPP NPs makes them luminescent probes for sensitive detection of Fe3+ ions with a low detection limit of 340 nM. Moreover, the luminescence of NaEuF 4 @TCPP NPs could be recovered by the addition of iron chelators. Benefiting from their good biocompatibility and stability in living cells, together with the characteristic of the reversible luminescence response, the lipo-coated NaEuF 4 @TCPP probes were successfully applied for real-time monitoring of Fe3+ ions in living HeLa cells. These results are expected to motivate the exploration of AIE-based lanthanide probes for sensing and biomedical applications. AIEgen-sensitized NaEuF 4 @TCPP nanocomposites exhibited an intense red emission and were applied for monitoring Fe3+ ions in living HeLa cells. [Display omitted] • AIEgen-sensitized nanocomposites were assembled from TCPP ligands and NaEuF 4 NCs. • NaEuF 4 @TCPP exhibited an intense red emission due to the AIE and antenna effects. • The red emission can be quenched by Fe3+ and recovered by subsequently adding EDTA. • NaEuF 4 @TCPP probes had a low LOD of 340 nM and a linear range of 0–60 μM for Fe3+. • NaEuF 4 @TCPP-Lipo probes were applied for monitoring Fe3+ ions in living HeLa cells. [ABSTRACT FROM AUTHOR]

Highlights: [•] Lanthanide-doped nanomaterials with unique optical properties are proposed as new-generation luminescent nanoprobes. [•] Lanthanide-doped nanoprobes for heterogeneous or homogeneous luminescent biodetection are surveyed. [•] Luminescent bioassays of a variety of analytes based on lanthanide-doped nanoprobes are reviewed. [Copyright &y& Elsevier]

Abstract: Currently, tripositive lanthanide (Ln3+) ions doped wide band-gap semiconductor nanocrystals (NCs) have been the focus of research interest due to their distinct optical properties and potential applications in optical devices and luminescent biolabels. Because of the low absorptions of parity-forbidden 4f–4f transitions for Ln3+, it is highly anticipated that the luminescence of Ln3+ ions embedded in wide band-gap NC lattices can be sensitized efficiently via exciton recombination in the host. For this purpose, the successful incorporation of Ln3+ into the lattices of semiconductor NCs is of utmost importance, which still remains intractable via conventional wet chemical methods. Here, the most recent progress in the optical spectroscopy of Ln3+ ions doped wide band-gap semiconductor NCs is discussed. Much attention was focused on the optical properties including electronic structures, luminescence dynamics, energy transfer as well as the up-conversion emissions of Ln3+ ions in ZnO, TiO2, SnO2 and In2O3 NCs that were synthesized in our laboratory using wet chemical methods. [Copyright &y& Elsevier]

Abstract: We report the synthesis of tetragonal-phase LiYF4 nanoparticles doped with upconverting lanthanide ions. The nanoparticles have been characterized by XRD, TEM, and luminescence decay studies. The size of the as-synthesized LiYF4 nanoparticles can be tuned by varying the precursor ratio of F to lanthanide ions. Passivated by oleic acid ligands, the LiYF4 nanoparticles can be readily dispersed in a wide range of nonpolar solvents including hexane, cyclohexane, dichloromethane, and toluene. The lanthanide-doped (Yb3+, Er3+, Tm3+, Ho3+) LiYF4 nanoparticles show intense upconversion emissions upon near infrared excitation at 980nm. By varying composition and concentration of the dopant ions, the color output can be precisely modulated under single wavelength excitation with a diode laser. [ABSTRACT FROM AUTHOR]

Rapid and accurate detection of phosphate (Pi) in complex biological fluid is of critical importance for timely warning of Pi accumulation and monitoring Pi related pathological process. Up to date, various luminescent probes have been developed for Pi determination in aqueous media. However, the huge obstacles of the current probes suffer from the inherent issues such as time-consuming, tedious preparation and unavoidable background interference during Pi detection. To circumvent this limitation, we proposed a universal and facile strategy to fabricate a novel sensitizer-Ln3+@surfactant micelle probe with time-resolved luminescent (TRL) superiority through the self-assembly of sensitizer, Ln3+ and surfactant. Through this design, the sensitizer-Ln3+ chelate can be encapsulated into the surfactant constructed micelle and Ln3+ luminescence can be substantially lighted up through the effective energy transfer from the coordinated sensitizer and the assistance of Triton X-100. Such high TRL signal can be sensitively and specifically quenched by Pi, which was attributed to the specific coordination competition between sensitizer and Pi towards Ln3+. Benefitting from the background-free interference and highly sensitive TRL response of the sensitizer-Ln3+@surfactant probe, we achieved the rapid, selective and sensitive detection of Pi in the range of 0.5–120 μM with a limit of detection (LOD) of 0.19 μM. Furthermore, the accuracy of the proposed method based on the Ln3+ involved micelle probes was further verified through the quantitation of Pi in real biological samples. [Display omitted] • A rapid and accurate platform was developed for Pi detection in complex biological fluids. • The probe was constructed through the self-assembly of sensitizer ligand, Ln3+ and surfactant. • The probe exhibited highly sensitized Ln3+ luminescence with time-resolved superiority. • Such high Ln3+ luminescence can be sensitively and specifically quenched by Pi. • The proposed strategy opens up a new avenue for the potential application of Ln3+-based probe. [ABSTRACT FROM AUTHOR]

Review: 364 refs. [ABSTRACT FROM AUTHOR]