Dual-color Emission Research Articles

Dual-color aggregation-induced emission nanoparticles for simultaneous lateral flow immunoassay of nitrofuran metabolites in aquatic products

Nitrofurans such as furaltadone and nitrofurantoin are a type of synthetic broad-spectrum antibiotics. Various fluorescent nanomaterials have been used as labeling materials in immunochromatographic assays (ICAs) for nitrofurans detection. However, previous fluorescent nanomaterials can undergo aggregation-caused quenching, leading to a decrease in the detection sensitivity. In this study, we developed a multiplex immunochromatographic assay (mICA) based on dual-color aggregation-induced emission nanoparticles (AIENPs) as signal labels for the simultaneous detection of 3-amino-5-morpholino-methyl-1,3-oxazolidinone (AMOZ) and 1-aminohydantoin (AHD), which were the metabolites of furaltadone and nitrofurantoin, respectively. Under optimal conditions, the cut-off values of the mICA for derivatized AMOZ (2-NP-AMOZ) and AHD (2-NP-AHD) reached up to 3 and 5 ng/mL, respectively. These values are at least 166-and 200-fold higher than those of the commercial gold nanoparticles (GNPs)-based test strip, respectively. Furthermore, the test strip was successfully applied to the samples, with acceptable recoveries in the range of 83.0–98.2%.

Dual-color light emission and optical waveguide behavior in core-shell heterostructures based on surface doping of cocrystal with rare earth ions

Organic core-shell structures/heterostructures are burgeoning as active photonic materials, i.e., optical waveguides, controllable multi-emissions, input-output optical logic gates. Here, a new conception that rare-earth (RE) ions as the surface dopants for the construction of organic cocrystal@RE complexes core-shell heterostructures was first proposed. Organic cocrystal Tpy-1,4-DITFB (Tpy = 2,2’:6′,2″-terpyridine; 1,4-DITFB = 1,4-diiodotetrafluorobenzenes) as inner-core has been designed. The RE ions of Eu(Ⅲ) and Tb(Ⅲ) are dopped on the surfaces of Tpy-1,4-DITFB cocrystal via epitaxial growth method. The effect of the compositions and morphologies of core-shell heterostructures on the optical behaviors were investagted via fluorescence spectroscopy. Spatially adjacent dual-color emission in the di-block core-shell heterostructures brings about tunable regulation of optical waveguide modes, offering potential applications for input/output optical logic gate and biomedical.

Rational design of a dual organelle-targeted photosensitizer with dual-color emission for photodynamic therapy and cell death self-reporting

Photosensitizers with organelle targeting play a vital role in image-guided photodynamic therapy (PDT). However, photosensitizers with the ability for dual-organelle targeting and dual-color emission are still lacking. Rational design of such photosensitizers with dual-organelle targeting and dual-color emission characteristics is of great significance for efficient enhancement of the performance of theranostics, but remains a challenge. Here we show a rational design to construct a dual organelle-targeted photosensitizer with dual-color emission by introducing cyano groups. To this end, two new photosensitizers TPA-2Py+ and TPA-2PyA+ with the electron donor (D: triphenylamine, TPA)-π bridge (π: benzene ring)-electron acceptor (A: vinyl/cyanovinyl pyridinium, Py/PyA) (D-π-A) structure were synthesized. Both of them exhibit effective singlet oxygen generation due to the strong D-π-A strength. TPA-2Py+ could light up the mitochondria of HeLa cells with near-infrared (NIR) emission. However, TPA-2PyA+ molecule possesses two additional cyano groups compared with TPA-2Py+, and enabled simultaneous locating into the lysosome and nucleolus with NIR and green fluorescence, respectively. Meanwhile, TPA-2PyA+ not only exhibited the ability to kill the cancer cells under light irradiation, but also to self-report the cell death in PDT via observing the change of emission color. This study offers an effective way for developing multifunctional photosensitizers for cancer theranostics.

Dual-Color Aggregation-Induced Emission Nanoparticles for Simultaneous Lateral Flow Immunoassay of Nitrofuran Metabolites in Aquatic Products

Dual-Color Aggregation-Induced Emission Nanoparticles for Simultaneous Lateral Flow Immunoassay of Nitrofuran Metabolites in Aquatic Products

Realizing White Emission of Single-Layer Dual-Color Perovskite Light-Emitting Devices by Modulating the Electroluminescence Emission Spectra.

Dual-color emission in a single perovskite layer would make perovskite light-emitting devices (PLEDs) more competitive compared with other display technologies. However, due to the carrier dynamics in a blended perovskite film and the low reaction activation energy of the halide exchange reaction, it is very difficult to achieve the dual-color emission in a perovskite layer. Here, dual-color electroluminescence (EL) emission in a single perovskite layer has been realized by slowing the energy transfer from wide-bandgap energy levels to narrow-bandgap energy levels. Moreover, the EL spectra can be controlled by modulating the composition of the perovskite layer. When the amount of CH3NH3I(MAI) in the precursor was varied, white emission with CIE coordinates of (0.33, 0.34) could be achieved. Our work proposes a new strategy for white emission from PLEDs. Also, the analysis and discussion of carrier dynamics in this work may help to enhance our understanding of the working mechanism of PLEDs.

Phase and photoluminescence analysis of dual-color emissive Eu3+-doped ZrO2 nanoparticles for advanced security features in anti-counterfeiting

In the present work, lower concentration-based dual-color emissive Eu3+-doped ZrO2 loose nanosized particles have been developed via precipitation method with sodium borohydride for the potential use of advanced security in anti-counterfeiting application. Stabilization of tetragonal zirconia up to moderate temperature has been explored considering lower Eu3+-concentration, particle size, and strain. Different phases of Eu3+-doped zirconia phosphors induce variation in photoluminescence characteristics such as photoluminescence emission, asymmetric ratio i.e. intensity of red to orange emission ratio, Commission International de I'Eclairage i.e. CIE chromaticity coordinates, and color emission. Also, phases of Eu3+-doped zirconia may produce multi-color emission, including white light depending on Eu3+-concentration, calcination temperature, and excitation wavelength. Photoluminescence emission spectra have been investigated at the excitation wavelengths of 254 nm, 365 nm, 393 nm, and 463 nm. Change in the peak position of the transition 5D0→7F2 and 5D0→7F1 in emission spectra indicates the presence of either mixed-phase or tetragonal zirconia polycrystals in Eu3+-doped zirconia samples. It was mainly due to the unlike site symmetry position of Eu3+-ions in different phases of Eu3+-doped zirconia. The intensity variation of the transitions in different phases of Eu3+-doped zirconia affects the asymmetric ratio, and thus produces shades of dual color emission, including near-white. In addition, the dual-color emissive sample, i.e., 0.5 mol% Eu3+-doped ZrO2 nanopowders, has been explored for anti-counterfeiting applications using a standard screen-printing technique.

Highly efficient Mn-doped CsPb(Br/Cl)3 mixed-halide perovskite via a simple large-scale synthesis method

Broadband emission Mn2+ doped lead halide perovskites are deemed as promising phosphor materials for solid state white light-emitting-diodes (WLEDs). Herein, we report a facile gram-scale synthesis of Mn-doped CsPb(Br/Cl)3 phosphors by doping MnCl2 into CsPbBr3 perovskite nanocrystals at room temperature. The obtained phosphors present dual-color emission with blue emission at 463 nm and red emission at 602 nm. Increasing MnCl2 doping amount can enhance the red emission while more 3-Aminopropyltrimethoxysilane (APTMS) ligands can repress Mn related impurity and provide high stability. Further, two kinds of WLEDs (monocomponnet and two-component) are demonstrated. The monocomponent WLED exhibits warm white light under various driving currents (30 mA–150 mA), and the two-component WLED shows good chromatic performance close to ideal white light (0.33, 0.33), demonstrating their potential applications in WLED devices.

Highly Transparent, Dual-Color Emission, Heterophase Cs3Cu2I5/CsCu2I3 Nanolayer for Transparent Luminescent Solar Concentrators.

Transparent luminescent solar concentrators (TLSCs) have been attracting wide attentions for their applications in transparent photovoltaic (PV) windows, smart greenhouses, and mobile electronics on account of the simple architecture and low-cost preparation. We report a novel strategy to fabricate TLSCs using the heterophase lead-free perovskites. The heterophase nanolayered films which combined CsCu2I3 and Cs3Cu2I5 were prepared in one step using a dual-source coevaporation technique. The CsCu2I3/Cs3Cu2I5 films exhibited UV light absorption, a high average visible transmission (AVT) of 86.70%, and dual-color white emission between 350 and 760 nm. Importantly, the TLSCs incorporated with the CsCu2I3/Cs3Cu2I5 films exhibited an impressive optical conversion efficiency of 1.15% under keeping a high AVT of 86.70%. Meanwhile, the TLSCs incorporated with the heterophase films showed considerable stability under ambient conditions. The CIE 1960 color coordinates (0.2082, 0.4680) of the TLSCs incorporated with the CsCu2I3/Cs3Cu2I5 films showed excellent aesthetic quality as compared with those of the TLSCs incorporated with lead-based perovskites. Our finding offers a strategy to prepare lead-free metal halides toward high-performance TLSCs and future transparent PV windows.

In situ preparation of Mn-doped perovskite nanocrystalline films and application to white light emitting devices

Mn-doped perovskite nanocrystals have promised new optoelectronic applications due to their unique material properties. In the present study, Mn-doped perovskite nanocrystalline films were prepared in situ in a polymer matrix. The Mn-doped perovskite nanocrystals (PNCs) had good crystallinity and uniform size/spatial distributions in the polymer film. Bright dual-color emission and the long lifetime of the excited state of the dopant were observed from the host exciton and the Mn2+ dopant, respectively. Furthermore, magnetism was observed in the optimal Mn2+ concentration, implying that magnetic coupling was achieved in the Mn-doped perovskite lattice. The Mn-doped perovskite films also showed superior stability against moisture. To demonstrate the practicality of this composite film, a white light emitting device was fabricated by combining a single composite film with a blue light emitting diode; the device showed a high-quality white light emission, and the Commission Internationale De L'Eclairage (CIE) chromaticity coordinate of the white light emitting diode (WLED) (0.361, 0.326) was close to the optimal white color index. In this single-layer WLED, self-absorption among the luminous multilayers in traditional white light emitting diodes can be avoided. The study findings revealed that Mn-doped perovskite nanocrystalline films have many exciting properties, which bodes well for the fundamental study and design of high-performance optoelectronic devices.

Transformation between the Dark and Bright Self-Trapped Excitons in Lead-Free Double-Perovskite Cs2NaBiCl6 under Pressure.

Understanding the relationships between the structure and the properties in lead-free double perovskites is significant for their applications in the optoelectronic field. Here the nonluminous Cs2NaBiCl6 crystal exhibits an unexpected broadband dual-color emission as the external pressure is increased to 6.77 GPa. The emission intensity is remarkably enhanced with further compression to 8.50 GPa. By analyzing the results of in situ high-pressure experiments and the density functional theory, we conclude that the dual-color emission is attributed to singlet self-trapped excitons (STEs) and triplet STEs, respectively. This phenomenon originates from the tilting and twisting of [BiCl6]3- caused by the transition of cubic Cs2NaBiCl6 to the tetragonal phase. Notably, the transformation between the dark and bright STEs in the Cs2NaBiCl6 crystal is demonstrated by ultrafast transient absorption experiments under different pressures. This work not only offers deep insight into the structure-property relationship in lead-free double perovskites but also opens the door for the design of new lead-free double perovskites.

Dual-color upconversion luminescence emission from Er:LiNbO3 on-chip ridge waveguides

Dual-color upconversion luminescence of Er3+-doped (0.1% mol) lithium-niobate-on-insulator (Er:LNOI) on-chip ridge waveguides is observed under the excitation of a continuous-wave 980-nm semiconductor laser, emitting both blue (at 450 nm) and green (at 528.3 nm) fluorescence emissions. The on-chip waveguides, with a propagation loss of around 3 dB/cm at 1550 nm, are fabricated by diamond blade dicing technique. The experimentally observed waveguiding modal profiles are in fairly good agreement with simulation results, indicating good quality of the fabricated waveguides. We believe this work will benefit the development of LiNbO3-based integrated photonics.

A label-free three potential ratiometric electrochemiluminescence immunosensor for cardiac troponin I based on N-(4-aminobutyl)-N-ethylisoluminol functionalized graphene quantum dots

• An ECL nanoluminophore with three potential-resolved emissions was synthesized. • A label-free three potential ratiometric immunosensor was built. • A low detection limit of 0.35 fg/mL was obtained for cardiac troponin I. • The developed strategy can effectively eliminate errors caused by environmental changes. In this work, we synthesized a novel ECL nanoluminophore N-(4-aminobutyl)-N-ethylisoluminol functionalized graphene quantum dots (ABEI@GQDs), which exhibited three completely potential-resolved dual-color ECL emissions with coreactant K 2 S 2 O 8 in an aqueous solution. Blue color ECL-1, orange red color ECL-2 and blue color ECL-3 were observed at peak potential of -0.58, -1.85 and 1.20 V, respectively. On this basis, a label-free three potential ratiometric ECL immunosensor was developed for detecting cardiac troponin I (cTnI) by layer-by-layer assembly of ABEI@GQDs and antibody on a chitosan modified fluorine doped tin oxide electrode. In the presence of cTnI, ECL-2 increased, whereas ECL-1 and ECL-3 changed slightly and synchronously. It was found that ECL-1/ECL-3 ratio almost unchanged with increasing the concentration of cTnI, which laid the foundation for self-correction analysis. Accordingly, three potential ratiometric strategy based on the ratio of three ECL peaks was established for the determination of cTnI with a linear dynamic range from 1.0 fg/mL to 5.0 pg/mL and a detection limit of 0.35 fg/mL, which was superior to most reported ECL methods. Moreover, the developed three potential ratiometric ECL immunosensor can effectively eliminate systematic errors caused by environmental changes and thus offers more precise detection results than two potential ratiometric ECL immonosensors.

Tunable Dual-Color Emission Perovskites via Post-Synthetic Modification Strategy for Near-Unity Photoluminescence Quantum Yield.

Lead halide perovskites (LHPs) with excellent performance have become promising materials for optoelectrical devices. However, as for the dual-color emission LHPs (DELHPs), the low photoluminescence quantum yield (PLQY) hinders their applications. Herein, a simple low-cost room-temperature post-synthetic modification strategy is used to achieve a near-unity PLQY of DELHPs. It is proven that ZnBr2 plays an important role as an inorganic ligand in reducing surface defects to induce a 95.4% increase in the radiative decay rate and a 99.5% decrease in the nonradiative decay rate in the treated DELHPs compared with the pristine DELHPs. The performance of the blue emission from the surface lattice is greatly improved via the modification of ZnBr2. DELHPs with different ratios of blue and green emissions are obtained by changing the specific surface area and ZnBr2 concentration. The distribution and mechanism of Zn2+ are discussed using the research model based on these DELHPs. The first example of the single-layer dual-color perovskite electroluminescence device is realized from DELHPs. This work provides a new perspective for improving the performance of DELHPs, which will greatly accelerate the development of emission materials of LHPs.

Tailoring Color-Tunable Dual Emissions of Mn2+-Alloyed Two-Dimensional Perovskite Quantum Wells

While manganese (Mn2+)-doped chalcogenide and perovskite CsPbX3 nanocrystals (NCs) have been extensively investigated, the research of color-tunable dual-emissive Mn2+-incorporated two-dimensional (2D) quantum wells (QWs) is limited. Here, we present alloyed Mn:(PEA)2PbBr4 2D perovskite QWs, achieving efficient dual-color emissions with high energy transfer efficiency (ΦET = 56%) and solid-state photoluminescence quantum yield (PLQY = 54%). Importantly, excitation and temperature are demonstrated as two efficient approaches to precisely modulate color-tunable dual emissions with excellent reversibility. The results indicate possible applications of such materials in photo-/thermal switchable markers and efficient thermometers for biomedical imaging and diagnostic investigations.

Lead-free p-type Mn:Cs3Cu2I5 perovskite with tunable dual-color emission through room-temperature grinding method

Lead-free p-type Mn:Cs3Cu2I5 perovskite with tunable dual-color emission through room-temperature grinding method

Precise Ligand Tuning Emission of Mn-Doped CsPbCl3 Nanocrystals by the Amount of Sulfonates.

Using Mn-doped CsPbCl3 nanocrystals (Mn:CsPbCl3 NCs) to improve perovskite's properties is becoming an important strategy. Here, we demonstrate a modified supersaturated recrystallization route to synthesize high-quality Mn:CsPbCl3 NCs at room temperature. Unprecedentedly, sulfonate ligands with various concentrations are shown to successfully tune the dual-color emission of Mn:CsPbCl3 NCs. Ultrafast transient absorption studies reveal that the host-to-dopant internal energy-transfer process involves the mediated traps. Interestingly, the dual-color emission is tuned via stabilizing mediated traps with a small amount of ligand (band edge (BE) emission reduces and Mn2+ emission increases), passivating the deep traps with a large amount of ligand (Mn2+ emission increases), and destroying Mn:CsPbCl3 NCs with too much ligand (both BE and Mn2+ emission is quenched). Furthermore, the ligand tuning Mn2+ emission exhibits quenching for Cu2+ with high sensitivity and selectivity. Our work provides a new strategy to tune the optical properties of Mn:CsPbCl3 NCs and presents its potential application in an optical detector.

Triplet-triplet annihilation upconversion with reversible emission-tunability induced by chemical-stimuli: a remote modulator for photocontrol isomerization.

Triplet-triplet annihilation upconversion (TTA-UC) has been widely studied, but a color-tunable TTA-UC system triggered by chemical stimuli has not yet been proposed. Herein, reversible acid/base switching of the TTA-UC emission wavelength is achieved for the first time by a simple platform, composed of a direct singlet-triplet (S0-T1) absorption photosensitizer, and proton-responsive 9,10-di(pyridin-4-yl)anthracene (DPyA) as an acceptor. The photosensitizer-acceptor pair exhibits efficient UC emission (quantum yield up to 3.3%, and anti-Stokes shift up to 0.92 eV) with remarkable contrast upon base/acid treatment (Δλem,max = 82 nm, 0.46 eV). In a proof-of-concept study, the color-adjustable TTA-UC emission was applied as a remote modulator to photo-control reversible chemical reactions for the first time. This platform enriches the portfolio of color-switchable TTA-UC, and the mechanism would inspire further development of smart UC systems and extend the application field of upconversion.

A unique self-reporting photosensitizer enabling simultaneous photodynamic therapy and real-time monitoring of phototheranostic process in a dynamic dual-color mode.

Phototheranostics has attracted great interest in cancer therapy. Small-molecule self-reporting photosensitizers, one kind of idea agent in phototheranostics, enables simultaneous photodynamic therapy (PDT) and feedback of therapeutic efficacy. However, previous such photosensitizers exclusively employed the change of single emission to monitor cell death, which can be disturbed by variations in photosensitizer concentration and the excitation intensity. Herein, we report a unique self-reporting photosensitizer TPA-3PyA+ constructed from a twisted triphenylamine unit (TPA), three benzene ring units and three cyanovinyl-pyridinium units (PyA) for PDT and its real-time monitoring in a dynamic dual-color mode. TPA-3PyA+ possesses a rotatable electron donor-π bridge-electron acceptor framework and exhibits high singlet oxygen quantum yield (124%) and a twisted intramolecular charge transfer (TICT) effect. TPA-3PyA+ not only enables effective staining of cancer cells with dual-color fluorescence due to the TICT effect but also shows excellent PDT performance. The simultaneous change in emission color, intensity and intracellular location of TPA-3PyA+ during cell death allows it to self-report cell death. Moreover, the change of dual-emission color allows distinguishing living and dead cells and effectively avoids interference in previous single-emission self-reporting photosensitizers. This work highlights the great potential of a self-reporting photosensitizer with dual-color emissions for efficient feedback of theranostics.

Ultrathin Monolayer Mn2+‐Alloyed 2D Perovskite Colloidal Quantum Wells

AbstractAtomically thin monolayer Mn2+‐alloyed 2D Ruddlesden–Popper (RP) perovskite colloidal quantum wells (CQWs) are demonstrated as efficiently tunable emitter with wide color gamut. Ultrathin character evidenced by the well‐controlled thickness of ≈1.8 nm, leads to alloying rather than doping mechanism reported previously, which facilitates uniform and large‐ratio substitution of Pb2+ by Mn2+ within the metal‐halide octahedra layer. Photoluminescence spectra reveal dual color emissions constituted by blue‐greenish intrinsic excitonic emission and reddish Mn2+ emission with a high photoluminescence quantum yield (PLQY) up to 32%. Two individual channels are created for precisely targeting the emission color in a wide gamut by finely controlling the excitonic emission via the chemical compositions of Br/I and the Mn2+ emission via the chemical compositions of Mn/Pb, respectively. Experimentally, high quality single‐component white emitter ultrathin CQWs are achieved with CIE coordinate value of (0.33, 0.32), 21% PLQY, and good film processibility. The results reveal great potential as applicant for next generation lighting and display technologies.

Dual-color upconversion photoluminescence induced by disordered Yb3+-Ti4+ pairs and defects in highly stable langbeinite-type Rb2Ti0.80Yb1.20(PO4)3 single crystal

Inorganic upconversion materials show significant importance in both basic research and applied area, and searching for suitable host material and understanding of fundamental photophysical process are particularly worth studying in upconversion application. Herein, a heavily Yb3+-substituted langbeinite-type Rb2Ti0.80Yb1.20(PO4)3 (RTYP) millimeter-sized single crystal, which has been successfully grown by high temperature solution method, exhibits efficient dual-color upconversion photoluminescence under 980 nm excitation. The lifetimes of two-photon blue emission and one-photon red emission are 4.1 μs and 17.1 μs, respectively. X-ray structural analyses reveal that the dual-color emissions are ascribed to disordered Yb3+-Ti4+ pairs and crystal defect, and the higher intensity of red emission is attributed to Yb3+-defect energy transfer activated by Ti4+. Notably, the blue emission originates from cooperative luminescence of Yb3+ dimer, and the red emission originates dominantly from the cooperative sensitization of the intrinsic defect caused by excited Yb3+ dimer. Moreover, RTYP with disordered structure shows high thermal stability up to 1,150 °C. This work not only demonstrates the promising potential of langbeinite-type materials in multicolor upconversion application, but also sheds light on the photophysical process associated with disordered crystal structure.