Bright Yellow Emission Research Articles

Dimension Tuning of All-Inorganic Ag-Based Metal Halides by Solvent Engineering.

Dimension growth of metal halides is important for its properties and applications. However, such dimension control of the metal halides is rarely reported in the literature and the growth mechanism is not clear yet. A minute difference of solvent properties can tremendously alter the process of nucleation and growth of crystals. Herein, an intriguing phenomenon of dimension tuning for Ag-based metal halides is reported. The 1D Cs2 AgCl3 crystals can be obtained in pure DMF while the 2D CsAgCl2 crystals are obtained in pure DMSO. Both exhibit bright yellow emission, which are derived from self-trapping excitons (STEs). The photoluminescence quantum yield (PLQY) of Cs2 AgCl3 (1D) and CsAgCl2 (2D) are 28.46 % and 20.61 %, respectively. In order to understand the mechanism of the dimension change, additional solvents (N,N-dimethylacetamide, DMAC, 1,3-Dimethyl-Tetrahydropyrimidin-2(1H)-one, DMPU) are also selected to process the precursor for crystal growth. By comparing the functional group, dielectric constant, and donor number among the four solvents, we find the donor number plays the predominant role in nucleation process for Cs2 AgCl3 and CsAgCl2 . This research reveals the relationship between coordination ability of the solvent and the dimension of metal halides.

Selective Passivation of Surface toward Bright Yellow Defective Emission of CdS Quantum Dots.

CdE (E = S, Se) quantum dots (QDs) with a broad and large Stokes shift PL emission have emerged as potential materials for white-light LEDs. However, this surface-related emission of nanocrystals is currently limited by low quantum efficiency. Herein, a convenient noninjected one-pot method at a relatively low temperature to prepare CdS QDs was readily achieved. The CdS-368 QD displays intense broad yellow emission in both solution and the solid state at room temperature. The coligation of organic and inorganic ligands passivates the electron trap states at the QD surface and suppresses nonradiative recombination, which is responsible for the high stability of colloids in organic solvents and the distinct fluorescence quantum yield.

Realizing efficient emission and triple‐mode photoluminescence switching in air‐stable tin(IV)‐based metal halides via antimony doping and rational structural modulation

AbstractRecently, many lead‐free metal halides with diverse structures and highly efficient emission have been reported. However, their poor stability and single‐mode emission color severely limit their applications. Herein, three homologous Sb3+‐doped zero‐dimensional (0D) air‐stable Sn(IV)‐based metal halides with different crystal structures were developed by inserting a single organic ligand into SnCl4 lattice, which brings different optical properties. Under photoexcitation, (C25H22P)SnCl5@Sb·CH4O (Sb3+−1) does not emit light, (C25H22P)2SnCl6@Sb‐α (Sb3+−2α) shines bright yellow emission with a photoluminescence quantum yield (PLQY) of 92%, and (C25H22P)2SnCl6@Sb‐β (Sb3+−2β) exhibits intense red emission with a PLQY of 78%. The above three compounds show quite different optical properties should be due to their different crystal structures and the lattice distortions. Particularly, Sb3+−1 can be successfully converted into Sb3+−2α under the treatment of C25H22PCl solution, accompanied by a transition from nonemission to efficient yellow emission, serving as a “turn‐on” photoluminescence (PL) switching. Parallelly, a reversible structure conversion between Sb3+−2α and Sb3+−2β was witnessed after dichloromethane or volatilization treatment, accompanied by yellow and red emission switching. Thereby, a triple‐mode tunable PL switching of off–onI–onII can be constructed in Sb3+‐doped Sn(IV)‐based compounds. Finally, we demonstrated the as‐synthesized compounds in fluorescent anticounterfeiting, information encryption, and optical logic gates.

2,3-Diarylquinoline -Based Iridium (III) Complexes: Synthesis, Photophysical Properties and DFT studies

Phosphorescent transition–metal complexes have received considerable interest in the development of efficient organic light-emitting diodes (OLEDs). Iridium complexes derived from heterocyclic ligands have brought a paradigm shift in the optoelectronic materials. Quinoline-based molecular architectures offer excellent materials for such applications due to their exceptional electronic properties, extended π-conjugation and strong ligand–metal binding. Iridium complexes of 2,3-diaryl quinolines with electron rich and electron deficient substituents were synthesized and their electronic properties were studied. Iridium complexes Ir1 and Ir2 bearing the electron withdrawing (-CF3) and electron donating (–OCH3) groups, respectively at the para position of the 2-phenyl ring of 2,3-diarylquinoline exhibited prominent absorption bands in the UV range. Further, the complex Ir3 with unsubstituted 2,3-diarylquinoline ligand and CF3 containing Ir1 showed intensive red phosphorescence near 603 and 611 nm, respectively due to metal-to-ligand and ligand-to-ligand (MLCT/LLCT) charge transfer characteristics. The photoluminescence (PL) spectra of the Ir4 complex derived from 2-phenylquinoline ligand exhibited a bright yellow phosphorescent emission at 589 nm. An additional C3 aryl group on the quinoline ring resulted in a red shift in the emission wavelength of Ir1 and Ir3 complexes compared to Ir4. The PL spectra of Ir2 on the other hand was weak, and blue-shifted to 489 nm, which can be attributed to a ligand-centered (LC) transition. The complexes showed photoluminescence quantum yield (PLQY) in the range of 0.004 to 0.17 and fluorescence lifetime ranged from 1.5 ns to 399 ns, implying the significant effect of the ligand structure on the properties of the complexes. Photophysical investigation of the complexed affirms these complexes to be potent materials for OLEDs fabrication. Cyclic voltammetry was used to investigate the electrochemical characteristics of Ir1-Ir4 complexes in acetonitrile. All of the complexes Ir1-Ir4 exhibited irreversible oxidation waves at 0.44 V, 0.23 V, 0.25 V, and 0.24 V respectively. Ir1-Ir4 complexes showed a reduction potential at −0.98 V, −0.96 V, −1.02 V and −0.97 V respectively. The DFT calculations were used to explore HOMO-LUMO energies, and NBO characteristics by B3LYP level of theory using ECP type double zeta (DZ) quality basis set LanL2DZ for metal and 6-311G(d) basis sets for non-metal atoms. The theoretical calculations were in significant agreement with the experimental studies of these complexes.

Anti‐Solvent Synthesis of Three‐Color Indium‐Based Halide Perovskite Microplate/Microcrystal Phosphors for High Color Rendering WLEDs

AbstractLead‐free halide perovskites are emerging as promising eco‐friendly candidates for next‐generation solid‐state lighting because of their nontoxicity and availability for broad emission. Herein, a modified room‐temperature anti‐solvent precipitation method is developed to synthesize the Sb3+‐doped, In‐based, lead‐free halide perovskites in microplate/microcrystal structure with different emission colors. The layered structure of InCl3 serves as the template for the growth of Cs2InCl5(H2O):Sb3+ microplate phosphors. Moreover, the presence of HCl not only improves the solubility of precursors, but also provides the acid etching effect. The resultant Sb3+‐doped Cs2InCl5(H2O) microplate phosphors show bright yellow emission with photoluminescence quantum yield up to 92.4%. Furthermore, Cs3InCl6:Sb3+ and Cs2NaInCl6:Sb3+ are synthesized through the similar method, which displays the bright green and deep‐blue emission, respectively. Subsequently, the proof‐of‐concept white light‐emitting diodes (WLEDs) are fabricated based on Cs2NaInCl6:Sb3+ + Cs2InCl5(H2O):Sb3+ and Cs2NaInCl6:Sb3+ + Cs3InCl6:Sb3+ + Cs2InCl5(H2O):Sb3+ phosphors, which achieves high‐quality white light with the color rendering index (CRI) of 91.6 and 95.4, respectively. The results greatly advance the development of lead‐free halide perovskite phosphors synthesis, which may offer new possibilities for high CRI WLEDs fabrication.

Solvatochromism of high-efficient and long-wavelength emissive carbon dots for wide-range water-sensing in organic solvents

A novel solvent-dependent fluorescent CDs (R-CDs) were prepared by solvothermal method from neutral red and urea precursors. The multicolor emissions ranging from blue to red from R-CDs could be achieved by tuning the solvents polarity. The highest quantum yield of 61.11% is achieved in R-CDs acetone solution with bright yellow emission at 565 nm. The solvent-dependent fluorescence is ascribed to the variation of CDs’ band-gap and surface potential, which are induced by polarity. R-CDs were used as a quantitative fluorescent sensor for detecting water in different solvents. An excellent linear relationship between water content (0–90%) and emission intensity is found in ethanol, methanol, acetonitrile, isopropanol, DMSO, and acetone. The limit of detection (LOD) is 1.55%, the recoveries range from 95% to 110%, and the relative standard deviations (RSD) are 0.15%–5.43%. All results indicate that our R-CDs for water sensing exhibit good linear relationship and accuracy.

Bulk assemblies of organic antimony chloride with multiple reversible photoluminescence switching for anti-counterfeiting and information encryption

Forgery and leakage of confidential information will bring great social harm and economic loss, so it is necessary to take simple and effective strategies to ensure information security. Here, two different zero-dimensional (0D) organic antimony chlorides of [Ph3S]2SbCl5·2C2H3N (1) and [Ph3S]2SbCl5 (2) were obtained by inserting the organic ligand of Ph3SCl (triphenylsulfonium chloride) into SbCl3 lattice via different chemical synthesis methods. Under photoexcitation, compound 1 shines bright yellow emission with a photoluminescence quantum efficiency (PLQE) of 98.2%, while compound 2 shows efficient red emission with a PLQE of 99.6%. Both of them exhibit dual-emission bands, which stem from the singlet self-trapped excitons (STEs) and triplet STEs, respectively. Particularly, the dynamic transformation processes between compounds 1 and 2 are witnessed via the acetonitrile (C2H3N) stripping/insertion under different external stimuli, which was demonstrated by the results of powder X-ray diffraction and photoluminescence (PL) spectra. In addition, the continuous heating of compound 2 can make the emission color change from red to yellow again, accompanied by the lattice distortion of [SbCl5]2- pyramid. Finally, the multiple anti-counterfeiting and information encryption models were fabricated based on the reversible PL switching of the title compounds under different external stimuli.

A selectivity-enhanced fluorescence imprinted sensor based on yellow-emission peptide nanodots for sensitive and visual smart detection of λ-cyhalothrin

The development of precise and efficient detection technologies to recognize λ-cyhalothrin (LC) in agricultural products has attracted attention worldwide due to its widespread use and notable toxic effects on humans. Herein, a novel fluorescence biomimetic nanosensor was elaborately designed based on Zn(II)-doped cyclo-ditryptophan (c-WW)-type peptide nanodots and incorporating molecularly imprinted polymer (c-WW/Zn-PNs@MIP) for LC assays. C-WW/Zn-PNs obtained by self-assembly with aromatic cyclic dipeptides as basic building blocks and coordination with Zn(II) have low-toxicity, photostability, and bright yellow fluorescence emission, as a sensitive signal transducer. High-affinity imprinting sites further endow c-WW/Zn-PNs@MIP with superior selectivity and reusability. Based on prominent merits, c-WW/Zn-PNs@MIP demonstrated a good linear range (1–360 μg/L) with a low limit of detection (LOD) (0.93 μg/L), fast kinetics in target capture (10 min), and strong practicability in the capture of LC from real samples (spiked recovery of 81.0–107.7%). Additionally, to attain onsite profiling of LC, a visual platform was developed by integrating c-WW/Zn-PNs@MIP with a smartphone-assisted optical device. This smart evaluation system can capture concentration-dependent fluorescent images and accurately digitize them, enabling quantitative analysis of LC. This study developed a fluorescent c-WW/Zn-PNs@MIP-based smart evaluation system as a novel platform for LC monitoring applications, which not only has enormous economic value but also great environmental health significance.

One-Dimensional Chiral Copper Iodide Chain-Like Structure Cu4 I4 (R/S-3-quinuclidinol)3 with Near-Unity Photoluminescence Quantum Yield and Efficient Circularly Polarized Luminescence.

Chiral organic-inorganic hybrid metal halide materials have shown great potential for circularly polarized luminescence (CPL) related applications for their tunable structures and efficient emissions. Here, this work combines the highly emissive Cu4 I4 cubane cluster with chiral organic ligand R/S-3-quinuclidinol, to construct a new type of 1D Cu-I chains, namely Cu4 I4 (R/S-3-quinuclidinol)3 , crystallizing in noncentrosymmetric monoclinic P21 space group. These enantiomorphic hybrids exhibit long-term stability and show bright yellow emission with a photoluminescence quantum yield (PLQY) close to 100%. Due to the successful chirality transfer from the chiral ligands to the inorganic backbone, the enantiomers show intriguing chiroptical properties, such as circular dichroism (CD) and CPL. The CPL dissymmetry factor (glum ) is measured to be ≈4×10-3 . Time-resolved photoluminescence (PL) measurements show long averaged decay lifetime up to 10 µs. The structural details within the Cu4 I4 reveal the chiral nature of these basic building units, which are significantly different than in the achiral case. This discovery provides new structural insights for the design of high performance CPL materials and their applications in light emitting devices.

Optical properties and mechanical induced phase transition of CsPb2Br5 and CsPbBr3 nanocrystals

The Cs-Pb-Br system possesses excellent optical properties and unique phase transition characteristics due to soft lattice structures. Herein, a simple and green synthetic method based on self-assembly in Dimethyl formamide (DMF) is proposed to prepare CsPb2Br5 nanocrystals (NCs) with typical tetragonal structure, which exhibit orange emission and small size around 3.87 nm. Interestingly, the phase transition from CsPb2Br5 to CsPbBr3 occurs easily in DMF through mechanical induction, while the metastable mixed-phase structural CsPbBr3 NCs with an average size of about 5 nm appear and show bright yellow emission. Afterwards, in combination with the supersaturation crystallization method, stable cubic CsPbBr3 NCs with 13 nm size are obtained and display the effective green emission. The synthesized CsPb2Br5 and steady-state CsPbBr3 NCs exhibit good optical stability in solution, while the metastable CsPbBr3 NCs undergo a change in emission from yellow to green with increasing time.

Superatom Pruning by Diphosphine Ligands as a Chemical Scissor.

A two-electron silver superatom, [Ag6{S2P(OiPr)2}4(dppm)2] (1), was synthesized by adding dppm (bis(diphenylphosphino)methane) into [Ag20{S2P(OiPr)2}12] (8e). It was characterized by single-crystal crystallography, multinuclear NMR spectroscopy, electrospray ionization-mass spectrometry, density functional theory (DFT), and time-dependent DFT calculations. The added dppm ligands, which carry out the nanocluster-to-nanocluster transformation, act as a chemical scissor to prune the nanocluster geometrically from an icosahedron-based Ag20 nanocluster (NC) to an octahedral Ag6 NC and electronically from eight-electron to two-electron. Eventually, dppm was involved in the protective shell to form a new heteroleptic NC. The temperature-dependent NMR spectroscopy confirms its fluxional behavior, showing the fast atomic movement at ambient temperature. Compound 1 exhibits a bright yellow emission under UV irradiation at ambient temperature with a quantum yield of 16.3%. This work demonstrates a new methodology to achieve nanocluster-to-nanocluster transformation via stepwise synthesis.

Rational Design of a Super-Alkali Compound with Reversible Photoluminescence

The zero-dimensional (0D) (H5O2)(C4H14N2S2)2BiCl8: Sb3+ single crystal is obtained by the cooling crystallization method. Surprisingly, this compound shows reversible photoluminescence (PL) upon H5O2+Cl- removal and insertion. To be specific, the release of H5O2+Cl- resulted in red-orange emission with a very low photoluminescence quantum yield (PLQY). While on the reuptake of it, a bright yellow emission with a nearly 10-fold increase of PLQY was observed. Density functional theory (DFT) calculations and temperature-dependent PL experiments reveal that significant [SbCl6]3- octahedron distortion induced by guest (H5O2+Cl-) removal at the ground state, especially at the excited state, is responsible for the disparate PL performance. Encouragingly, we also found that (C4H14N2S2)2BiCl7: Sb3+ exhibits a fast response (<3 s) to dilute hydrochloric acid with naked-eye perceivable PL color changes, rendering it a potential sensing material for hydrochloric acid.

Single molecule magnet features in luminescent lanthanide coordination polymers with heptacoordinate Dy/Yb(III) ions as nodes.

Two sets of 1D/2D lanthanide coordination polymers with formulas of Ln(oqa)3·2H2O [Hoqa = 2-(4-oxoquinolin-1(4H)-yl) acetic acid, Ln = Dy (1), Yb (2)] and Ln(oaa)2(HCOO)(H2O) [Hoaa = 2-(9-oxoacridin-10(9H)-yl) acetic acid, Ln = Dy (3), Yb (4)] have been synthesized and their physical properties were investigated. All four complexes are constructed from seven-coordinate lanthanide ions and corresponding organic linkers. The lanthanide ions in 1 and 2 adopt a pentagonal bipyramid coordination geometry, whereas the coordination geometry of lanthanide ions in 3 and 4 can be described as a capped octahedron. Slow magnetic relaxation behaviors were observed in these four products at a zero/non-zero static magnetic field. Complexes 1, 2 and 4 exhibit the characteristic emission of Ln(III) ions, whereas complex 3 shows ligand-based emission. Bright yellow light emission was also observed when a voltage was applied, demonstrating the potential of 1 for application in light-emitting diodes (LEDs). Compounds 3 and 4 are the first examples of lanthanide complexes based on Hoaa ligands.

Large-scale synthesis, mechanism, and application of a luminescent copper hydride nanocluster.

Elucidating the structure-property relationships of ultra-small metal nanocluster with basic nuclear is of great significance for understanding the evolution mechanism in both the structures and properties of polynuclear metal nanoclusters. In this study, an ultra-small copper hydride (CuH for short) nanocluster was simply synthesized with high yield, and the large-scale preparation was also achieved. Single crystal X-ray diffractometer (SC-XRD) analysis shows that this copper NC contains a tetrahedral Cu4 core co-capped by four PPh2Py ligands and two Cl in which the existence of the central H atom in tetrahedron was further identified experimentally and theoretically. This CuH nanocluster exhibits bright yellow emission, which is proved to be the mixture of phosphorescence and fluorescence by the sensitivity of both emission intensity and lifetime to O2. Furthermore, the temperature-dependent emission spectra and density functional theory (DFT) calculations suggest that the luminescence of CuH mainly originates from the metal-to-ligand charge transfer and cluster-centered triplet excited states. This work offers new insights into understanding the structure-property relationship of basic nuclear CuH nanocluster.

Second harmonic generation from symmetry breaking stimulated by mixed organic cations in zero-dimensional hybrid metal halides.

Mixing cations with different chemical properties to induce the generation of asymmetric structures is a new approach for tuning the optical properties of hybrid organic-inorganic metal halides (HOIMHs). In this study, zero-dimensional (C9N3H15)(C9H13SO)MBr6 (M = Bi/Sb, [C9N3H15]2+ = [(C4N2H10)(C5NH5)]2+ and [C9H14SO]+ = [CH3(C6H4)OS(CH3)2]+) are synthesized. Two different cations cause both compounds to crystallize in the polar space group P212121, thus resulting in significant phase matchable second harmonic generation under a 1064 nm laser excitation. Thus, (C9N3H15)(C9H13SO)BiBr6 and (C9N3H15)(C9H13SO)SbBr6 exhibit intensities that are approximately 1.8 and 1.7 times that of KH2PO4, respectively. The results of density functional theory calculations show that both (C9N3H15)(C9H13SO)BiBr6 and (C9N3H15)(C9H13SO)SbBr6 exhibit direct bandgaps of 2.95 and 2.81 eV, respectively. Additionally, because of the distortion of the inorganic octahedra, (C9N3H15)(C9H13SO)SbBr6 exhibited bright yellow emission at room temperature, which is attributed to ns2 fluorescence emission. We believe that the symmetry of the HOIMH crystal structure can be broken by introducing spatially differentiated bifunctional organic cations, which consequently enables even-order nonlinear activities.

Preparation of fluorescein-modified polymer dots and their application in chiral discrimination of lysine enantiomers.

Fluorescein-functionalized fluorescent polymer dots (F-PDs) were prepared by a facile one-pot method by magnetic stirring under mild conditions based on carboxymethylcellulose (CMC) and fluorescein as the precursors. The obtained F-PDs exhibited a nanoscale size of 3.2 ± 1.1nm, excellent water solubility, and bright yellow fluorescence emission with a fluorescence quantum yield of 12.0%. The fluorescent probe displays rapid and sensitive chiral discrimination for lysine focused on different complexation abilities between lysine enantiomers and Cu2+. The concentration of L-lysine in the range4 to 14mM (R2 = 0.997) wasmeasured by the fluorescence intensity ratio (I513/I429); the exitation wavelength was set to λex = 365nm. The detection limit was 0.28mM (3σ/slope). Importantly, this sensor accurately predicted the enantiomeric excess (ee) of lysine enantiomers at the designed concentration (lysine: 20mM; Cu2+: 10mM) ranges. Theproposed sensor was successfully applied to determineL-lys (recovery: 95.8-101%; RSD: 0.465-3.34%) and ee values (recovery: 98.5-102%; RSD: 2.61-3.21%) in human urine samples using the standard addition method.

Variable luminnescence chromaticity and energy transfer in CaZnOS: Pr3+, Mn2+ by ultraviolet and blue excitations

Pr3+ and Mn2+ co-doped CaZnOS phosphors are prepared by high-temperature solid state reaction method and the photoluminescence property is investigated systematically. Under 283 ​nm ultraviolet and 447 ​nm blue light excitations, green emission from CaZnOS, Pr3+ and red emission from Mn2+ are obtained and the emission color is modulated from green to yellow and red by adjusting the ratio of Pr3+ to Mn2+ concentration. The photoluminescence process under 283 ​nm and 447 ​nm excitations are dependent on energy transfer from CaZnOS to Pr3+ and Mn2+, as well as energy transfer from Pr3+ to Mn2+. The energy transfer mechanism between Pr3+ and Mn2+ is confirmed to be dipole-quadrupole interaction. Particularly, under 447 ​nm blue excitation, CaZnOS: 1%Pr3+, 3%Mn2+ exhibits bright yellow emission with chromaticity coordinates of (0.372, 0.428) and quantum yields of 46.37%, implying a potential application in blue-chip excited white light emitting diodes (W-LEDs).

Thermal-evaporation-deposited CsCu2I3 films with self-trapped excitons for electrically driven yellow light-emitting diodes

Ternary copper halide CsCu2I3 has shown tremendous potentials in addressing the lead toxicity and instability issues of lead-based perovskites light-emitting diodes (LEDs) toward practical applications. However, the development of CsCu2I3-based LEDs still faces great challenges due to the difficulties in fabricating high-quality CsCu2I3 films and designing well-matched device configurations caused by the inherent wide bandgap. Herein, a thermal evaporation technique conjunction with post-annealing treatment was employed to fabricate high-quality CsCu2I3 films, which show a dense and smooth morphology, an excellent heat/ultraviolet light/moisture/oxygen stability, and a bright broadband yellow emission centered at 550 nm. Temperature-dependent photoluminescence and femtosecond transient absorption spectroscopy measurements indicate that the broadband emission with large Stokes shifts of CsCu2I3 films originates from self-trapped excitons-related recombination. Furthermore, a stepwise “energy ladder” hole transport layer of PEDOT:PSS/Poly-TPD/PVK was applied in CsCu2I3-based LEDs to improve the hole injection and charge carrier recombination, leading to an increased device performances. By collaborative optimization, a yellow LED emitting at 550 nm with a peak luminance of 219.6 cd/m2, an external quantum efficiency of 0.49 %, and a half-lifetime of 48.5 min is realized, providing a new idea for the development of environmental-friendly LEDs based on copper halide systems.

Charge compensation and solid-state lighting application for dysprosium-activated Ba2TeP2O9 phosphor

In this study, trivalent dysprosium (Dy 3+ ) activators were doped into barium tellurooxyphosphate Ba 2 TeP 2 O 9 (BTP) by a solid-state sintering procedure, where alkali metal (A = Li, Na, and K) ions co-doped as charge compensator were aimed at improving the luminescent performance. To investigate optical absorption behavior, the electronic structure of the BTP host was realized via the density functional theory (DFT) method. The BTP:Dy 3+ phosphor excited by 349 nm shows bright yellow emission. When the concentration of the Dy 3+ activator is greater than 0.03 mol, concentration quenching occurs owing to dipole–dipole interaction. After doping 0.03 mol A + ions into the BTP:0.03Dy 3+ phosphor, the emission intensity of BTP:0.03Dy 3+ enhances by 1.18 (Li + ), 1.43 (Na + ), and 2.32 times (K + ). Additionally, the BTP:0.03Dy 3+ ,0.03 K + phosphor exhibits satisfactory thermal stability. A white light-emitting diode (w-LED) was successfully fabricated from the BTP:0.03Dy 3+ ,0.03 K + and commercial blue phosphors with a 365 nm LED chip. The study reveals that the BTP:0.03Dy 3+ ,0.03 K + phosphor is a prospective yellow-emitting candidate for w-LED. • Due to the asymmetric coordination of Dy 3+ , the yellow-emitting of BTP:Dy 3+ is stronger than its blue-emitting. • Co-doping K + into the host can both produce minimal lattice distortion and reduce the structural vacancy. • The thermostability of BTP:0.03Dy 3+ ,0.03 K + is competitive with that of the commercial yellow phosphor. • The concentration quenching mechanism is the dipole–dipole interaction.

A new fast-responding fluorimetric “turn-on” sensor based on benzothiazole-phenanthridine for the sensitive, selective, and reversible detection of Cu2+ in real water samples and its use in bio-imaging

This article describes a new chemosensor, 2-(benzo[d]thiazol-2-yl)-6-(7,8,13,14-tetrahydrodibenzo [a, i] phenanthridin-5-yl) phenol (BTPP), which is based on the combination of phenanthridine and benzothiazole groups for the sensitive and selective detection of Cu2+. Following the successful synthesis of BTPP in a single step, the molecular structure of BTPP was verified by 1H NMR, 13C NMR, mass spectrometry, and X-ray single-crystal analysis. These sensors exhibit high optical selectivity for the Cu2+ ion across a broad spectrum of other common metal ions in ACN/H2O (1:1) solution, resulting in an extraordinary fluorescence off-on response with a very low Limit of Detection (LOD) value. When Cu2+ was added to the compound BTPP, it displayed outstanding properties such as bright yellow emission, rapid reaction time (10 s), detection over a wide pH range (pH = 6–12), and reversibility with glutathione(GSH). FT-IR analysis, 1H NMR titration experiments, HRMS, and Job's plot analysis were used to determine the mechanism of BTPP's binding to Cu2+. Inspired by these remarkable sensing characteristics, we successfully used BTPP to detect Cu2+ in paper strip-based detection, ambient water samples, and fluorescent bio-imaging in E. coli bacteria with satisfying results.