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Lanthanide-doped upconversion (UC) luminescent materials display multicolor emissions, making them ideal for a variety of applications, such as multi-channel biological imaging, fluorescence encryption, anti-counterfeiting, and 3D display. Manipulating the UC emissions of the luminescent materials with a fixed composition is crucial for their applications. Herein, we propose a facile strategy to achieve pulse-width-dependent multicolor UC emissions in NaYF4:Yb/Er/Tm nanocrystals. Upon excitation with a 980 nm continuous-wave laser diode, Er3+ ions in NaYF4:20%Yb,15%Er,1%Tm nanocrystals exhibited UC emissions with a red-to-green (R/G) ratio of 11.3. Nevertheless, by employing a 980 nm pulse laser with pulse widths from 0.1 to 10 ms, the UC R/G ratio can be easily adjusted from 0.9 to 11.3, resulting in continuous and remarkable color transformation from green, yellow, orange, to red. By virtue of the dynamic luminescence color variation of these NaYF4:20%Yb,15%Er,1%Tm nanocrystals, we demonstrated their potential applications in the areas of anti-counterfeiting and information encryption. These findings provide deep insights into the excited-state dynamics and energy transfer of Er3+ in NaYF4:Yb/Er/Tm nanocrystals upon 980 nm pulse excitation, which may pave the way for designing multicolor UC materials toward versatile 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]

Lanthanide ion (Ln3+)‐doped halide double perovskites (DPs) have evoked tremendous interest due to their unique optical properties. However, Ln3+ ions in these DPs still suffer from weak emissions due to their parity‐forbidden 4f–4f electronic transitions. Herein, the local electronic structure of Ln3+‐doped Cs2NaInCl6 DPs is unveiled. Benefiting from the localized electrons of [YbCl6]3− octahedron in Cs2NaInCl6 DPs, an efficient strategy of Cl−‐Yb3+ charge transfer sensitization is proposed to obtain intense near‐infrared (NIR) luminescence of Ln3+. NIR photoluminescence (PL) quantum yield (QY) up to 39.4% of Yb3+ in Cs2NaInCl6 is achieved, which is more than three orders of magnitude higher than that (0.1%) in the well‐established Cs2AgInCl6 via conventional self‐trapped excitons sensitization. Density functional theory calculation and Bader charge analysis indicate that the [YbCl6]3− octahedron is strongly localized in Cs2NaInCl6:Yb3+, which facilitates the Cl−‐Yb3+ charge transfer process. The Cl−‐Yb3+ charge transfer sensitization mechanism in Cs2NaInCl6:Yb3+ is further verified by temperature‐dependent steady‐state and transient PL spectra. Furthermore, efficient NIR emission of Er3+ with the NIR PLQY of 7.9% via the Cl−‐Yb3+ charge transfer sensitization is realized. These findings provide fundamental insights into the optical manipulation of Ln3+‐doped halide DPs, thus laying a foundation for the future design of efficient NIR‐emitting DPs. [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]

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]

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]

Stimuli‐responsive nanoagents, which simultaneously satisfy normal tissue clearance and tumor‐specific responsive treatment, are highly attractive for precise cancer theranostics. Herein, we develop a unique template‐induced self‐assembly strategy for the exquisitely controlled synthesis of self‐assembled lanthanide (Ln3+) nucleotide nanoparticles (LNNPs) with amorphous structure and tunable size from sub‐5 nm to 105 nm. By virtue of the low‐temperature (10 K) and high‐resolution spectroscopy, the local site symmetry of Ln3+ in LNNPs is unraveled for the first time. The proposed LNNPs are further demonstrated to possess the ability for highly efficient loading and tumor‐microenvironment‐responsive release of doxorubicin. Particularly, sub‐5 nm LNNPs not only exhibit excellent biocompatibility and predominant renal‐clearance performance, but also enable efficient tumor retention. These findings reveal the great potential of LNNPs as a new generation of therapeutic platform to overcome the dilemma between efficient therapy and long‐term toxicity of nanoagents for future clinical applications. [ABSTRACT FROM AUTHOR]

Stimuli‐responsive nanoagents, which simultaneously satisfy normal tissue clearance and tumor‐specific responsive treatment, are highly attractive for precise cancer theranostics. Herein, we develop a unique template‐induced self‐assembly strategy for the exquisitely controlled synthesis of self‐assembled lanthanide (Ln3+) nucleotide nanoparticles (LNNPs) with amorphous structure and tunable size from sub‐5 nm to 105 nm. By virtue of the low‐temperature (10 K) and high‐resolution spectroscopy, the local site symmetry of Ln3+ in LNNPs is unraveled for the first time. The proposed LNNPs are further demonstrated to possess the ability for highly efficient loading and tumor‐microenvironment‐responsive release of doxorubicin. Particularly, sub‐5 nm LNNPs not only exhibit excellent biocompatibility and predominant renal‐clearance performance, but also enable efficient tumor retention. These findings reveal the great potential of LNNPs as a new generation of therapeutic platform to overcome the dilemma between efficient therapy and long‐term toxicity of nanoagents for future clinical applications. [ABSTRACT FROM AUTHOR]

Fundamental understanding of the effect of doping on the optical properties of 3D double perovskites (DPs) especially the dynamics of self‐trapped excitons (STEs) is of vital importance for their optoelectronic applications. Herein, a unique strategy via Cu+ doping to achieve efficient STE emission in the alloyed lead‐free Cs2(Ag/Na)InCl6 DPs is reported. A small amount (1.0 mol%) of Cu+ doping results in boosted STE emission in the crystals, with photoluminescence (PL) quantum yield increasing from 19.0% to 62.6% and excitation band shifting from 310 to 365 nm. Temperature‐dependent PL and femtosecond transient absorption spectroscopies reveal that the remarkable PL enhancement originates from the increased radiative recombination rate and density of STEs, as a result of symmetry breakdown of the STE wavefunction at the octahedral Ag+ site. These findings provide deep insights into the STE dynamics in Cu+‐doped Cs2(Ag/Na)InCl6, thereby laying a foundation for the future design of new lead‐free DPs with efficient STE emission. [ABSTRACT FROM AUTHOR]

Highly efficient luminescence of AgInTe2:Zn/ZnS nanocrystals with the maximum NIR-II quantum yield of 25.2% has been designed through elaborately manipulating the structure to reduce their internal and surface defects. These AgInTe2:Zn/ZnS nanoprobes were employed for sensitive homogeneous biodetection of xanthine oxidase with the limit of detection down to 25 nU L−1. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln3+)‐doped upconversion (UC) nanoprobes, which have drawn extensive attention for various bioapplications, usually suffer from small absorption cross‐sections and weak luminescence intensity of Ln3+ ions. Herein, we report the controlled synthesis of a new class of Ln3+‐doped UC nanoprobes based on CsLu2F7:Yb/Er nanocrystals (NCs), which can effectively increase the intersystem crossing (ISC) efficiency from singlet excited state to triplet excited state of IR808 up to 99.3 % through the heavy atom effect. By virtue of the efficient triplet sensitization of IR808, the optimal UC luminescence (UCL) intensity of IR808‐modified CsLu2F7:Yb/Er NCs is enhanced by 1309 times upon excitation at 808 nm. Benefiting from the intense dye‐triplet‐sensitized UCL, the nanoprobes are demonstrated for sensitive assay of extracellular and intracellular hypochlorite with an 808‐nm/980‐nm dual excited ratiometric strategy. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln3+)‐doped upconversion (UC) nanoprobes, which have drawn extensive attention for various bioapplications, usually suffer from small absorption cross‐sections and weak luminescence intensity of Ln3+ ions. Herein, we report the controlled synthesis of a new class of Ln3+‐doped UC nanoprobes based on CsLu2F7:Yb/Er nanocrystals (NCs), which can effectively increase the intersystem crossing (ISC) efficiency from singlet excited state to triplet excited state of IR808 up to 99.3 % through the heavy atom effect. By virtue of the efficient triplet sensitization of IR808, the optimal UC luminescence (UCL) intensity of IR808‐modified CsLu2F7:Yb/Er NCs is enhanced by 1309 times upon excitation at 808 nm. Benefiting from the intense dye‐triplet‐sensitized UCL, the nanoprobes are demonstrated for sensitive assay of extracellular and intracellular hypochlorite with an 808‐nm/980‐nm dual excited ratiometric strategy. [ABSTRACT FROM AUTHOR]

Understanding the origin of temperature‐dependent bandgap in inorganic lead‐halide perovskites is essential and important for their applications in photovoltaics and optoelectronics. Herein, it is found that the temperature dependence of bandgap in CsPbBr3 perovskites is variable with material dimensionality. In contrast to the monotonous redshift ordinarily observed in bulk‐like CsPbBr3 nanocrystals (NCs), the bandgap of 2D CsPbBr3 nanoplatelets (NPLs) exhibits an initial blueshift then redshift trend with decreasing temperature (290–10 K). The Bose–Einstein two‐oscillator modeling manifests that the blueshift‐redshift crossover of bandgap in the NPLs is attributed to the significantly larger weight of contribution from electron‐optical phonon interaction to the bandgap renormalization in the NPLs than in the NCs. These new findings may gain deep insights into the origin of bandgap shift with temperature for both fundamentals and applications of perovskite semiconductor materials. [ABSTRACT FROM AUTHOR]

All‐inorganic lead‐free metal halides doped with ns2‐metal ions have shown great promise in optoelectronics and photovoltaics owing to their superior optical properties. Herein, a strategy is reported for tailoring the optical properties of 0D A2InX5⋅H2O and A3InX6 (A = Cs, Rb; X = Cl, Br) crystals via Sb3+ doping, and the excited‐state dynamics of Sb3+ is unveiled through temperature‐dependent photoluminescence (PL) and femtosecond transient absorption spectroscopies. Owing to the spatially confined 0D structure of the In‐based halides, Sb3+ ions experience a strong Jahn–Taller distortion on the excited state, which results in intense PL from Sb3+ with a broad emission band and a large Stokes shift. Through the control of A cation and the octahedral unit, tunable Sb3+ emissions (490−750 nm) with PL quantum yields up to 91.8% are achieved in these 0D In‐based halides. These findings provide fundamental insights into the excited‐state dynamics of Sb3+ in 0D metal halides, thus laying a foundation for future design of luminescent lead‐free 0D metal halides through ns2‐metal doping towards versatile applications. [ABSTRACT FROM AUTHOR]

Herein, we report the design of novel ultraviolet luminescent CsPbCl3 nanocrystals (NCs) with the emission peak at 381 nm through doping of cadmium ions. Subsequently, a surface passivation strategy with CdCl2 is adopted to improve their photoluminescence quantum yield (PLQY) with the maximum value of 60.5 %, which is 67 times higher than that of the pristine counterparts. The PLQY of the surface passivated NCs remains over 50 % after one week while the pristine NCs show negligible emission. By virtue of density functional theory calculations, we reveal that the higher PLQY and better stability after surface passivation may result from the significant elimination of surface chloride vacancy (VCl) defects. These findings provide fundamental insights into the optical manipulation of metal ion‐doped CsPbCl3 NCs. [ABSTRACT FROM AUTHOR]

Herein, we report the design of novel ultraviolet luminescent CsPbCl3 nanocrystals (NCs) with the emission peak at 381 nm through doping of cadmium ions. Subsequently, a surface passivation strategy with CdCl2 is adopted to improve their photoluminescence quantum yield (PLQY) with the maximum value of 60.5 %, which is 67 times higher than that of the pristine counterparts. The PLQY of the surface passivated NCs remains over 50 % after one week while the pristine NCs show negligible emission. By virtue of density functional theory calculations, we reveal that the higher PLQY and better stability after surface passivation may result from the significant elimination of surface chloride vacancy (VCl) defects. These findings provide fundamental insights into the optical manipulation of metal ion‐doped CsPbCl3 NCs. [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]

Optical thermal sensing holds great promise for disease theranostics. However, traditional ratiometric thermometry methods, in which intensity ratio of two nonoverlapping emissions is defined as the thermosensitive parameter, may have a limited accuracy in temperature read‐out due to the deleterious interference from wavelength‐ and temperature‐dependent photon attenuation in tissue. To overcome this limitation, a dual‐excitation decoding strategy based on NIR hybrid nanocomposites comprising self‐assembled quantum dots (QDs) and Nd3+ doped fluoride nanocrystals (NCs) is proposed for thermal sensing. Upon excitation at 808 nm, the intensity ratio of two emissions at identical wavelength (1057 nm) from QDs and NCs, respectively, is defined as the thermometric parameter R. By employing another 830 nm laser beam following the same optical path as 808 nm laser to exclusively excite QDs, the two overlapping emissions can be easily decoded. The acquired R proves to be inert to the detection depth in tissue, with a minimized temperature reading error of ≈2.3 °C at 35 °C (at a depth of ≈1.1 mm), while the traditional thermometry mode based on the nonoverlapping 1025 and 863 nm emissions may exhibit a large error of ≈43.0 °C. The insights provided by this work pave the way toward high‐accuracy deep‐tissue biosensing. [ABSTRACT FROM AUTHOR]

Multiplexed intracellular detection is desirable in biomedical sciences for its higher efficiency and accuracy compared to the single-analyte detection. However, it is very challenging to construct nanoprobes that possess multiple fluorescent signals to recognize the different intracellular species synchronously. Herein, we proposed a novel dual-excitation/dual-emission upconversion strategy for multiplexed detection through the design of upconversion nanoparticles (UCNP) loaded with two dyes for sensitization and quenching of the upconversion luminescence (UCL), respectively. Based on the two independent energy transfer processes of near-infrared (NIR) dye IR845 to UCNP and UCNP to visible dye PAPS-Zn, ClO− and Zn2+ were simultaneously detected with a limit of detection (LOD) of 41.4 and 10.5 nM, respectively. By utilizing a purpose-built 830/980 nm dual-laser confocal microscope, both intrinsic and exogenous ClO− and Zn2+ in live MCF-7 cells have been accurately quantified. Such dual-excitation/dual-emission ratiometric UCL detection mode enables not only monitoring multiple intracellular analytes but also eliminating the detection deviation caused by inhomogeneous probe distribution in cells. Through modulation of NIR dye and visible dye with other reactive groups, the nanoprobes can be extended to analyze various intracellular species, which provides a promising tool to study the biological activities in live cells and diagnose diseases. [ABSTRACT FROM AUTHOR]

The synthesis of hydrophilic lanthanide‐doped nanocrystals (Ln3+‐NCs) with molecular recognition ability for bioimaging currently remains a challenge. Herein, we present an effective strategy to circumvent this bottleneck by encapsulating Ln3+‐NCs in graphene oxide (NCs@GO). Monodisperse NCs@GO was prepared by optimizing GO size and core–shell structure of NaYF4:Yb,Er@NaYF4, thus combining the intense visible/near‐infrared II (NIR‐II) luminescence of NCs and the unique surface properties and biomedical functions of GO. Such nanostructures not only feature broad solvent dispersibility, efficient cell uptake, and excellent biocompatibility but also enable further modifications with various agents such as DNA, proteins, or nanoparticles without tedious procedures. Moreover, we demonstrate in proof‐of‐concept experiments that NCs@GO can realize simultaneous intracellular tracking and microRNA‐21 visualization, as well as highly sensitive in vivo tumor‐targeted NIR‐II imaging at 1525 nm. [ABSTRACT FROM AUTHOR]

The synthesis of hydrophilic lanthanide‐doped nanocrystals (Ln3+‐NCs) with molecular recognition ability for bioimaging currently remains a challenge. Herein, we present an effective strategy to circumvent this bottleneck by encapsulating Ln3+‐NCs in graphene oxide (NCs@GO). Monodisperse NCs@GO was prepared by optimizing GO size and core–shell structure of NaYF4:Yb,Er@NaYF4, thus combining the intense visible/near‐infrared II (NIR‐II) luminescence of NCs and the unique surface properties and biomedical functions of GO. Such nanostructures not only feature broad solvent dispersibility, efficient cell uptake, and excellent biocompatibility but also enable further modifications with various agents such as DNA, proteins, or nanoparticles without tedious procedures. Moreover, we demonstrate in proof‐of‐concept experiments that NCs@GO can realize simultaneous intracellular tracking and microRNA‐21 visualization, as well as highly sensitive in vivo tumor‐targeted NIR‐II imaging at 1525 nm. [ABSTRACT FROM AUTHOR]

CuInS2 semiconductor nanocrystals (NCs) exhibit large absorption coefficient, size-dependent photoluminescence and low toxicity, making them excellent candidates in a variety of bioapplications. However, precise control of both their composition and morphology to improve the luminescent efficiency remains a great challenge via conventional direct synthesis. Herein, we present a novel low-temperature template synthesis of highly efficient luminescent CuInS2 nanoprobes from In2S3 NCs via a facile cation exchange strategy. The proposed strategy enables synthesis of a series of CuInS2 NCs with broad size tunability from 2.2 to 29.6 nm. Through rationally manipulating the stoichiometry of Cu/In, highly efficient luminescence of CuInS2 with the maximum quantum yield of 28.6% has been achieved, which is about one order of magnitude improvement relative to that of directly synthesized NCs. By virtue of the intense emission of CuInS2 nanoprobes, we exemplify their application in sensitive homogeneous biodetection for an important biomolecule of adenosine triphosphate (ATP) with the limit of detection down to 49.3 nM. Moreover, the CulnS2 nanoprobes are explored for ATP-targeted cancer cell imaging, thus revealing their great potentials in the field of cancer diagnosis and prognosis. [ABSTRACT FROM AUTHOR]

Lanthanide-based luminescent anti-counterfeiting materials are widely used in various kinds of products. However, the emission color of traditional lanthanide-based luminescent materials usually remains nearly unaltered upon different excitation lights, which may only work for single-level anti-counterfeiting. Herein, the NaYbF4:2%Er@NaYF4 core/shell nanoplates (NPs) with "chameleon-like" optical behavior are developed. These NPs display single-band red or green downshifting (DS) emission upon excitation at 377 or 490 nm, respectively. Upon 980 nm excitation, the color of upconversion (UC) emission can be finely tuned from green to yellow, and to red with increasing the excitation power density from 0.1 to 4.0 W/cm2. The proposed materials readily integrate the advantages of excitation wavelength-dependent DS single-band emissions and sensitive excitation power-dependent UC multicolor emissions in one and the same material, which has never been reported before. Particularly, the proposed NPs exhibit excellent performance as security labels on trademark tag and security ink on painting, thus revealing the great potential of these lanthanide-doped fluoride NPs in multilevel anti-counterfeiting applications. [ABSTRACT FROM AUTHOR]

Applications of persistent luminescence phosphors as night or dark‐light vision materials in many technological fields have fueled up a growing demand for rational control over the emission profiles of the phosphors. This, however, remains a daunting challenge. Now a unique strategy is reported to fine‐tune the persistent luminescence by using all‐inorganic CsPbX3 (X=Cl, Br, and I) perovskite quantum dots (PeQDs) as efficient light‐conversion materials. Full‐spectrum persistent luminescence with wavelengths covering the entire visible spectral region is achieved through tailoring of the PeQD band gap, in parallel with narrow bandwidth of PeQDs and highly synchronized afterglow decay owing to the single energy storage source. These findings break through the limitations of traditional afterglow phosphors, thereby opening up opportunities for persistent luminescence materials for applications such as a white‐emitting persistent light source and dark‐light multicolor displays. [ABSTRACT FROM AUTHOR]

Applications of persistent luminescence phosphors as night or dark‐light vision materials in many technological fields have fueled up a growing demand for rational control over the emission profiles of the phosphors. This, however, remains a daunting challenge. Now a unique strategy is reported to fine‐tune the persistent luminescence by using all‐inorganic CsPbX3 (X=Cl, Br, and I) perovskite quantum dots (PeQDs) as efficient light‐conversion materials. Full‐spectrum persistent luminescence with wavelengths covering the entire visible spectral region is achieved through tailoring of the PeQD band gap, in parallel with narrow bandwidth of PeQDs and highly synchronized afterglow decay owing to the single energy storage source. These findings break through the limitations of traditional afterglow phosphors, thereby opening up opportunities for persistent luminescence materials for applications such as a white‐emitting persistent light source and dark‐light multicolor displays. [ABSTRACT FROM AUTHOR]

The accurate detection of blood glucose is of critical importance in the diagnosis and management of diabetes and its complications. Herein, we report a novel strategy based on an upconversion nanoparticles-polydopamine (UCNPs-PDA) nanosystem for the accurate detection of glucose in human serum and whole blood through a simple blending of test samples with ligand-free UCNPs, dopamine, and glucose oxidase (GOx). Owing to the high affinity of lanthanide ions exposed on the surface of ligand-free UCNPs, dopamine monomers could spontaneously attach to the UCNPs and further polymerize to form a PDA shell, resulting in a remarkable upconversion luminescence (UCL) quenching (97.4%) of UCNPs under 980-nm excitation. Such UCL quenching can be effectively inhibited by H2O2 produced from the GOx/glucose enzymatic reaction, thus enabling the detection of H2O2 or glucose based on the UCL quenching/inhibition bioassay. Owing to the highly sensitive UCL response and background-free interference of the UCNPs-PDA nanosystem, we achieved a sensitive, selective, and high-throughput bioassay for glucose in human serum and whole blood, thereby revealing the great potential of the UCNPs-PDA nanosystem for the accurate detection of blood glucose or other H2O2-generated biomolecules in clinical bioassays. [ABSTRACT FROM AUTHOR]

Sensitive detection of cancer biomarker microRNAs (miRNAs) is of vital importance for cancer diagnosis and treatment. Nonetheless, the detection sensitivity in the existing miRNA bioassays is severely limited by the structural characteristics of miRNA (including small length and high sequence homology) because most of these methods are based on target amplification. Herein, we report a novel approach to sensitive and specific detection of low-abundance miRNA via a unique strategy of nanoprobe dissolution-enhanced fluorescence amplification, in which a capture probe featuring molecular beacon structure is designed. By means of this strategy, miRNA-21 was detected in a linear range from 10 fM to 100 pM with a detection limit as low as 1.38 fM. High selectivity of the newly developed biosensor was demonstrated by the good discrimination against a target with a single-base mismatch. Furthermore, this assay was used for the detection of miRNA-21 added into fetal bovine serum samples with the recovery in the range of 90.2%-108% and coefficients of variation below 10.1%, indicating its promising applications to RNA immunoassays and early cancer diagnosis. [ABSTRACT FROM AUTHOR]

The Ce- and Sm-co-doped NaBa(BO) phosphors were synthesized by a traditional high-temperature solid-state reaction method. The morphology of NaBa(BO) phosphors was characterized by scanning electron microscope. The crystal structures of Ce- and/or Sm-doped NaBa(BO) phosphors were studied by X-ray powder diffraction. The results suggested that Ce occupied the two Ba sites, while Sm might enter into the interstices of NaBa(BO) crystal. The four emission lines of Ce situating at two Ba sites can be well distinguished by Gaussian fitting. The emission lines from Sm in NaBa(BO) were significantly enhanced by 25-fold when co-doped with 1 mol% Ce ions. New Sm emission center characterized by the intensified excitation band at around 472 nm was produced as a result of Ce co-doping, which significantly extended the excitation wavelength region for matching both the near-ultraviolet and blue-light-emitting diodes. [ABSTRACT FROM AUTHOR]

Lanthanide (Ln3+)-doped nanocrystals (NCs) have shown great promise in diverse bioapplications. Exploring new host materials to realize efficient downshifting (DS) and upconversion (UC) luminescence is a goal of general concern. Ln3+-doped oxybromides, which bring together the advantages of high chemical/thermal stability of oxides and low phonon energy of bromides, have been rarely reported so far. Herein, we report the synthesis of monodisperse tetragonal-phase LaOBr:Ln3+ NCs via a modified thermal decomposition approach. Ln3+ dopants in LaOBr NCs occupying surface and lattice sites were verified based on high-resolution photoluminescence spectra of Eu3+ at 10 K. Intense DS emissions were observed in Ce3+ and Ce3+/Tb3+ doped LaOBr NCs upon excitation at 353.0 nm, which is far from the deep-UV absorption band of proteins. Moreover, UC properties of LaOBr:Yb3+/Ho3+ and Yb3+/Er3+ NCs were comprehensively surveyed upon near-infrared excitation at 980 nm. Particularly, the red-to-green ratio can be markedly increased from 0.1 to ∼300 in LaOBr:Yb3+/Er3+ NCs, resulting in high-chromatic-purity single-band red UC emission. Furthermore, we have employed the LaOBr:Ln3+ NCs for cancer cell imaging by virtue of their superior optical properties, showing great potential of LaOBr:Ln3+ nanoprobes in bioimaging. [ABSTRACT FROM AUTHOR]

Exploring novel lanthanide-activated upconversion nanoparticles with distinctive spectral fingerprints and emission lifetimes has long been a great concern for extended optical applications. Herein, we report the study of photon upconversion emissions in Yb3+–Tb3+ and Yb3+–Eu3+ activated nanoparticles with near-infrared excitation. In these nanoparticles, a high content of Yb3+ is required for the simultaneous excitation of two Yb3+ ions, yielding a Yb3+ dimer with a higher excited energy to upconvert photons onto Tb3+ and Eu3+. The optimum doping concentration of Yb3+ ions for Yb3+–Tb3+ and Yb3+–Eu3+ pairs was determined to be 80% and 60%, respectively, which are much higher than that of Yb3+–Er3+/Tm3+ pairs. Notably, the upconversion emission lifetime of the as-prepared nanoparticles was prolonged to 2.3 ms (Tb3+) and 4.0 ms (Eu3+), respectively. Through the epitaxial growth of a Nd3+ doped shell layer, the upconversion emissions of Tb3+ and Eu3+ were intensified 25-fold. At the same time, an extra excitation band in the shorter near-infrared region from Nd3+ at 808 nm was achieved. Moreover, the emissions of Tm3+ were employed to compensate for those of Tb3+ and Eu3+ for multicolor emissions. These results highlight the upconversion emissions of Tb3+ and Eu3+ for potential multicolor imaging and multiplexed detection applications. [ABSTRACT FROM AUTHOR]

The complete and correct sentence is as follows: The phonon energy ( I h i SB phonon sb ) and the Huang-Rhys factor ( I S i ) were calculated to be B 20.6 meV b and B 46.4 b , respectively. At the bottom of page 3, in the right-hand column, the fitted phonon energy and the Huang-Rhys factor are incorrect. Tailoring the Broadband Emission in All-Inorganic Lead-Free 0D In-Based Halides through Sb3+ Doping. [Extracted from the article]

Rattle structure is a topic of great interest in design and application of nanomaterials due to the unique core@void@shell architecture and the integration of functions. Herein, we developed a novel 'ship-in-a-bottle' method to fabricate upconverting (UC) luminescent nanorattles by incorporating lanthanide-doped fluorides into hollow mesoporous silica. The size of nanorattles and the filling amount of fluorides can be well controlled. In addition, the modification of silica shell (with phenylene and amine groups) and the variation of efficient UC fluorides (NaYF:Yb,Er, NaLuF:Yb,Er, NaGdF:Yb,Er and LiYF:Yb,Er) were readily achieved. The resulting nanorattles exhibited a high capacity and pH-dependent release of the anti-cancer drug doxorubicin (DOX). Furthermore, we employed these nanorattles in proof-of-concept UC-monitoring drug release by utilizing the energy transfer process from UC fluorides to DOX, thus revealing the great potential of the nanorattles as efficient cancer theranostic agent. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Nanocomposites consisting of upconversion nanoparticles (UCPs) and plasmonic materials have been widely explored for bio-imaging and cancer photothermal therapy (PTT). However, several challenges, including incomprehensible efficiency of energy transfer processes and optimization of the conditions for plasmon-induced photothermal effects, still exist. In this study, we fabricated NaYF4:Yb3+/Er3+ nanoparticles (NPs) conjugated with gold nanomaterials (Au NMs), such as Au NPs and gold nanorods (Au NRs). NaYF4:Yb3+/Er3+ NPs were used as photoconverters, which could emit green and red light under excitation of a 980 nm laser; Au NPs and Au NRs were also prepared and used as heat producers. The silica shell was further coated around UCPs to improve biocompatibility and as a bridge linking UCPs and the Au NMs. Most importantly, the thickness of the silica shell was tuned precisely to investigate the effective distance of the plasmonic field for heat induction. Energy transfer was confirmed by the declining UCL photoluminescence and emission decay time after connecting to the Au NMs. Moreover, a simulative model was built using the finite element method to assess the differences in heat generation between UCP@SiO2-NPs and UCP@SiO2-NRs. The surfaces of the hybrid nanocomposites were modified with folic acid to improve the specific targeting to cancer cells. The performance of the modified hybrid nanocomposites in PTT for OECM-1 oral cancer cells was evaluated. [ABSTRACT FROM AUTHOR]