Integrated NIR-II light sources via Cr4+-doped wafer-scale composite ceramics for enhanced image sensing

A series of amphiphilic aza‐BODIPY dyes ( 1a‐d ) bearing two julolidine units at 1,7‐positions of the azadipyrromethene core and hydrophilic oligo(ethylene glycol) chains at the 3,5‐phenyls were synthesized and characterized. All dyes feature broad, panchromatic absorption bands from 350 nm up to 1000–1100 nm in CH 2 Cl 2 and exhibit near‐infrared (NIR‐II) emission bands up to 1400 nm. Solvent‐dependent absorption and fluorescence spectroscopic studies reveal pronounced positive solvatochromism of these dyes and further Lippert–Mataga analyses reveal their efficient intramolecular charge transfer character. The optical properties of these dyes are strongly influenced by the substitution patterns as well as the linker structures (–OCH 2 – or –N(CH 2 ) 2 ) for the hydrophilic moieties at the 3,5‐phenyls, which is further elucidated by density functional theory calculations. Notably, dye 1b exhibits the most red‐shifted emission (1109 nm in DMSO) with a high fluorescence quantum yield (2.0%). In addition, all dyes display reversible spectroscopic pH‐response. These results underscore the promising application potential of these new aza‐BODIPY dyes.

ABSTRACT Cr 3+ emission can well cover the NIR‐I region (700–950 nm), while Ni 2+ emission typically extends across the NIR‐II region (1000–1700 nm), making the Cr 3+ –Ni 2+ co‐doped phosphors among the most promising ultrabroadband NIR emitters for phosphor‐converted light‐emitting diodes (pc‐LEDs). However, a pronounced gap or even spectral discontinuity between the two emission bands results in a severely imbalanced photon flux across the spectrum, thereby degrading multicomponent spectral detection accuracy and significantly limiting the practical applications of such NIR pc‐LED devices. Here, we report a superstoichiometric spinel MgO· n Ga 2 O 3 :Cr 3+ ,Ni 2+ ( n > 1) phosphor, in which the excess Ga 2 O 3 increases the degree of cation inversion to achieve a long‐wavelength Cr 3+ emission at 895 nm, substantially elevating the spectral gap height to a state‐of‐the‐art value of ≈36%. Moreover, efficient energy transfer from Cr 3+ to Ni 2+ enables the optimized MgO·1.2Ga 2 O 3 :Cr 3+ ,Ni 2+ phosphor to demonstrate a high internal quantum efficiency of 97% and excellent thermal stability. Finally, the as‐fabricated NIR pc‐LED delivers an exceptional photoelectric efficiency of 21% at 20 mA and a maximum NIR output power of 62 mW at 350 mA. This work establishes a new pathway toward next‐generation compact ultrabroadband NIR pc‐LEDs featuring unprecedented spectral flatness and superior optoelectronic performance.

Lanthanide-doped upconversion nanoparticles (UCNPs) have emerged as promising platforms for bioimaging and theranostics owing to their unique ability to convert near-infrared (NIR) excitation into visible emission. Controlling their emission behavior is critical for both mechanistic understanding and biomedical translation. In this work, we synthesized NaYF4: Yb3+, Er3+, Tm3+ UCNPs via a hydrothermal route and systematically investigated their power-dependent luminescence. Log–log slope analysis clarified photon participation in different emission bands, revealed competition between Yb3+→Er3+ and Yb3+→Tm3+ pathways, and identified saturation effects at higher excitation power. Based on these insights, the nanoparticles were functionalized with silica–TPGS to improve colloidal stability, dispersibility, and biocompatibility. Preliminary biological evaluation with MCF-7 breast cancer cells demonstrated efficient uptake, bright intracellular luminescence, and dose-dependent cytotoxicity (GI₅₀ = 0.26 ± 0.02 ppm). These findings highlight excitation-power control as a powerful strategy for tailoring UCNP emission properties, laying the foundation for advanced applications in ratiometric sensing, multicolor imaging, and cancer theranostics.

Apart from benzene, aromatic compounds, crucial in biological and chemical processes, were conspicuously absent from the interstellar inventory before 2017, despite extensive searches. Since then, high-resolution laboratory rotational spectroscopic studies in combination with extremely high-sensitivity spectral line surveys have led to the discovery of numerous cyclic and aromatic molecules in the starless dark cloud TMC-1, a source previously thought unsuitable for such chemical complexity. Detections include polycyclic aromatic hydrocarbons (PAHs) and their cyano derivatives with as many as seven fused rings. Discrepancies of more than four orders of magnitude between observed and predicted abundances challenge established astrochemical models. The detection of benzonitrile in other molecular clouds further suggests that aromatic chemistry is common in space. New spectroscopic studies and analysis methods hold promise to refine models of PAH formation and better constrain PAH stabilities in the diffuse gas, thereby aiding in the identification of the carriers of the diffuse interstellar and unidentified infrared emission bands, and potentially reshaping our understanding of the chemical pathways that link interstellar organic molecules to the origins of terrestrial carbon.

Large CsPbBr3 nanocrystals show unique photoluminescence properties of an ultralong lifetime, supernarrow line width, and high exciton efficiency; however, the mechanism of the ultralong photoluminescence lifetime is still not clear. In this work, we investigated the size- and temperature-dependent photoluminescence properties of CsPbBr3 nanocrystals with steady and transient photoluminescence spectra. At cryogenic temperature, small CsPbBr3 nanocrystals (8.6 and 10.6 nm) show a nearly single-peak emission of confined excitons, while large CsPbBr3 nanocrystals (12.9, 17.5, and 25.8 nm) exhibit two band emissions with a short component lifetime (several nanoseconds) of free excitons and a long component lifetime (hundreds of nanoseconds) of bound excitons. For large CsPbBr3 nanocrystals, the ratio of photoluminescence emission between bound and free excitons varied from 7:3 to 3:7 with increasing temperature. Based on the experimental results, we propose a mechanism of thermally activated transition between bound and free excitons to explain the ultralong photoluminescence lifetime in large CsPbBr3 nanocrystals. In all, this understanding may exploit these thermally activated transition effects to design advanced quantum emitters.

Hydrogenated polycyclic aromatic hydrocarbons have been proposed both as potential carriers of the unidentified infrared (UIR) bands and as catalytic sites for H2 formation in astrophysical environments. We report the infrared (IR) spectra for five monohydrogenated phenanthrene isomers (1-, 2-, 3-, 4-, and 9-HC14H10), generated by electron bombardment of phenanthrene (C14H10) codeposited with para-hydrogen onto a cryogenic substrate. Distinct absorption signatures intensified during extended dark storage of the matrix, while subsequent irradiation at 423, 380, 315, and 223 nm produced characteristic photochemical responses, enabling classification into five distinct groups. Assignments to individual isomers were supported by comparison with scaled harmonic vibrational wavenumbers and IR intensities calculated at the B3LYP/6-311++G(d,p) level of theory. Hydrogen addition was observed at all accessible nonbridging carbon sites. The resulting spectra exhibit intense features in the 11.5-14.5 μm region, indicating that these species are unlikely to represent major contributors to the UIR emission bands.

Detection of luminescence emission from TiO2 during alpha particle irradiation

Citrate plays a multifaceted and crucial role as a key intermediate in the Krebs cycle (citric acid cycle or TCA cycle), the central metabolic pathway for energy production or a source of ATP in aerobic organisms. Besides a metabolic regulator, dysregulation of citrate levels is intricately linked to the pathology of multiple diseases, including metabolism in cancer cells. Abnormal citrate concentrations have been associated with kidney stones, inflammation, metabolic disorders, cancers, non-alcoholic fatty liver diseases, neurological disorders, etc., highlighting its diagnostic and prognostic value. Therefore, the selective recognition and monitoring of changes in the citrate levels in physiological conditions is useful for advancing our understanding of these diseases, enabling early diagnosis and guiding effective therapeutic strategies. Developing a selective receptor for citrate is challenging due to its structural resemblance to competing biological anions (PO43-, NO3-, tartrate, HCO3-, etc.) and its lower levels than other common anions in biological media. The uniquely attractive optical properties of luminescent Ln(III) probes, narrow emission bands, photobleaching resistance, photostability, especially the long luminescence lifetime, and the hard oxophilic nature of tripositive Ln(III) ions make them ideal for time-gated luminescence measurements for trinegative hard [citrate]3- ions with an enhanced S/N ratio and minimized scattering and autofluorescence from the media. We report here the rationale and fundamental design principles for an emissive Eu(III) probe, [Eu(EDTA3AQ)(H2O)3]Cl (Eu.1), containing EDTA3AQ2- as an EDTA-bisamide framework linked to two 3-aminoquinolines as antennae for the selective sensing of [citrate]3- as an important regulatory metabolite at physiological pH using highly sensitive and selective time-resolved luminescence (TRL) from Eu.1. The facile displacement of three labile inner-sphere H2O molecules and coordinative unsaturation at the Eu(III) centre in Eu.1 satisfying the steric demand for preferential 1 : 1 binding of [citrate]3- at Eu(III) are found to be important design criteria, which were comprehensively studied using various solution-based spectroscopic studies and DFT. The [EuL-citrate] complexation, solution speciation, effects of variation of the coordination number of Eu(III), and the change in hydration numbers (q) were studied and validated to gain an insightful correlation of the rationale of Eu.1 probe design based on the luminescence sensing mechanism of Eu.1 for citrate. The strong electrostatic binding of [citrate]3-via displacing H2O molecules in the 1st-sphere in Eu.1 suppresses the nonradiative vibrational energy transfer (VET), resulting in enhanced TRL from the f-f transitions, and thus acts as a reversible, selective and sensitive turn-ON sensor at the ppb level of citrate using both the TRL intensity and lifetime-based modalities.

Exciton coherence is a phenomenon involving collective electronic transition dipole moments of molecular aggregates with interesting photophysical behaviors such as superradiance and subradiance in J- and H-type aggregates, respectively. Although singlet aggregate excitons have been extensively studied, the understanding of triplet exciton coherence in terms of specific conditions is still lacking due to limited experimental observations. Here, by synthesizing model organic compounds of fluorene monomer, dimer, trimer, and polymer, we systematically studied their photoluminescence in both solution and aggregation states. Strong triplet exciton coherence is present in polyfluorene aggregates, including nanoparticles, microparticles, and thin films, and is manifested either as HJ-aggregate phosphorescence or delayed fluorescence depending on the size of these aggregates. Notably, in the phosphorescence state, the polyfluorene polymer exhibits an unusually sharp atomic-spectrum-like emission band with a narrow full width at half maximum (FWHM) of only 0.05 eV (14 nm) and the longest lifetime of 0.63 s. This study shows that the size of organic aggregates is essential in dictating organic exciton dynamics in the solid state and holds importance for the development of advanced optoelectronic technologies.

ABSTRACT This study experimentally investigates the thermophysical properties and droplet combustion behavior of boron and silane boron nanofuels. Silane boron nanoparticles were prepared by coating boron nanoparticles with (3-aminopropyl)triethoxysilane (APTS), and nanofuels were formulated by dispersing 2 and 4 wt.% of boron/silane boron nanoparticles in butanol. Span 80 (1 and 2 wt.%) was added to induce puffing, an explosion at the droplet surface caused by vapor formation inside the droplet, which enhances combustion through droplet atomization. The addition of nanoparticles and surfactant did not significantly affect viscosity or surface tension. However, boron nanofuels containing Span 80 showed poor dispersion stability at room temperature and at 100°C, promoting puffing and increased boron flame luminosity due to enhanced atomization. In contrast, silane boron nanofuels exhibited improved dispersion stability, resulting in weaker puffing and reduced boron flame luminosity. The effective burning rate increased for silane boron droplets due to enhanced thermal conductivity. Boron flame emission was analyzed using a spectrometer at BO2 emission bands of 493, 517, 547, and 578 nm. Overall emission intensities were lower for silane boron nanofuels because reduced puffing resulted in weaker boron flame emission. For both fuels, Span 80 increased BO2 emission intensity through surfactant-induced puffing.

Abstract It has been proposed that the cyclic rising tone in frequency observed in rising tone quasi‐periodic (QP) fast magnetosonic waves is due to the cyclic diffusion of the inner energy edge of the source proton shell distribution toward lower energies. Linear theory shows that as the inner edge of the proton shell diffuses inwards the unstable frequency rises leading to a rising tone. We present the first observations of this diffusion of the proton shell distribution for this type of wave event, observed by the HOPE instrument on Van Allen Probes B, where this diffusion is clearly observed in two back‐to‐back QP wave cycles. Linear instability is performed on the observed proton shell distribution, and the linear growth rate is compared with the observed wave frequency; the linear theory applied to the observed proton shell distributions was qualitatively but not quantitatively consistent with the observed wave frequencies. Nearby Waveform Receiver burst mode measurements showed that the spacing of the emission bands in frequency was very close to the proton cyclotron frequency f cP , suggesting a near source. However, a ±2 nT spacecraft induced oscillation at ½ the spacecraft spin period in the background magnetic field magnitude could not allow us to conclude that the emission bands where at integer multiples of f cP , a stronger condition for source proximity.

To modulate the structure and optical properties of Cr3+-activated Y3Al5O12 garnet with typical narrowband near-infrared (NIR) emitting, cation substitution was implemented to establish novel Y3-xCaxAl5-xSnxO12:yCr3+ broadband NIR phosphors in this work. Density functional theory calculations, Rietveld refinement, X-ray photoelectron spectroscopy, and UV-vis-NIR/photoluminescence spectroscopy analysis clearly elucidated that the equimolar Ca2+ and Sn4+ doping led to the expansion of the lattice and the enhanced distortion degree of the [(Al,Sn,Cr)O6] octahedron. They thus resulted in a reduction in the crystal-field magnitude and in a massive redshift and spectral broadening of the emission band. The optimal x = 1.5/y = 0.06 phosphor manifested wide-band NIR emission with a center at ∼764 nm and a full width at half-maximum of ∼135 nm, a high luminous efficiency (internal quantum efficiency = 75.6% and external quantum efficiency = 25.1%), and favorable thermal stability (74.5% at 423 K). The manufactured pc-NIR-LED device using this optimal phosphor exhibited satisfactory NIR output power (∼21.1 mW) and efficiency (8.53%), signifying that this garnet phosphor has potential for application in the construction of pc-NIR-LEDs for night vision, noninvasive medical diagnosis, and nondestructive detection.

We report in this work highly efficient, temporally stable, and multicolor chemiluminescence of CdSe/CdS/ZnS quantum dots (QDs) boosted by radicals that are in situ electrogenerated near the electrode surface. Typically, electrochemical oxidation of tri-n-propylamine (TPrA), a tertiary amine, generates radical cation (TPrA•+) and radical (TPrA•). Then, TPrA• and TPrA•+ sequentially inject an electron and a hole to the valence and conduction bands of a QD to populate the excited state (QD*). In this pathway, a negatively charged QD (QD-) is formed as the key intermediate, instead of fragile positively charged QD+, thus producing highly stable and efficient luminescence. Moreover, this pathway is also identical to the so-called low-oxidation-potential electrochemiluminescence route of the gold standard luminophore, tris(2,2'-bipyridyl)ruthenium (Ru(bpy)3 2+), and therefore fully fit for microbead-based bioassays. Considering their high emission efficiency (∼5 times higher than Ru(bpy)3 2+ under same condition), narrow emission bands and tunable wavelengths, these QDs hold great promise as luminophores in ultrasensitive and multiplexed microbead-based bioassays.

In this study, Li 4‐x / 3 Ti 5−2x / 3 Sm x O 12 ( x = 0, 0.01, 0.05, 0.10) compounds were synthesized via a facile and cost‐effective solid‐state reaction method to investigate their structural, photoluminescent, electrochemical, and supercapacitive properties. X‐ray diffraction (XRD) analysis confirmed that Sm 3+ ions were successfully incorporated into the Li 4 Ti 5 O 12 (LTO) spinel lattice without altering the crystal structure, indicating high phase purity and structural stability upon doping. Scanning electron microscopy (SEM) revealed homogeneous particle morphology with subtle changes in grain size, while BET surface area analysis provided insights into surface area variations due to Sm 3+ substitution. Raman spectroscopy further verified the integrity of the spinel framework and highlighted lattice distortions associated with dopant incorporation. Photoluminescence (PL) spectroscopy showed that both undoped and Sm 3+ ‐doped LTO samples exhibit broad emission bands in the 600–850 nm range, primarily attributed to intrinsic oxygen vacancy‐related defect states. Notably, Sm 3+ doping enhanced the emission intensity by approximately 30%, demonstrating its effectiveness in promoting radiative recombination processes relevant for optical applications such as white light‐emitting diodes (W‐LEDs). Electrochemical evaluations, including galvanostatic charge–discharge (GCD) and cyclic voltammetry (CV) measurements, revealed that Sm 3+ incorporation improved lithium‐ion diffusion kinetics and electronic conductivity, resulting in enhanced reversible capacity and rate capability. Furthermore, supercapacitor performance was assessed through capacitance measurements at various current densities. The Sm‐doped LTO exhibited high specific capacitances of 325.58 F/g at 1 A/g (C1), decreasing gradually to 222.69 F/g at 20 A/g (C20), demonstrating excellent rate capability. The cyclic stability test at 20 A/g showed a capacity retention consistent with high durability. CV profiles recorded at 0/0.65 V and GCD curves at 0/0.52 V confirmed stable electrochemical behavior under operational conditions. These combined results highlight the dual‐functional role of Sm 3+ doping in simultaneously tuning optical emission and electrochemical properties, while also providing promising supercapacitive performance. The synergistic enhancement underscores the potential of Sm 3+ ‐doped Li 4 Ti 5 O 12 as a multifunctional material for integrated photonic and energy storage applications, including next‐generation W‐LEDs, lithium‐ion batteries, and high‐performance supercapacitors. Formun Üstü. Formun Altı.

Ultra-broadband emission spanning red to near-infrared range from Cr3+ doped Y2Mo3O12 with negative thermal expansion for high-performance plant lighting.

Developing efficient and stable blue organic light-emitting diodes (OLEDs) remains challenging due to the inherent trade-off between efficiency and operational lifetime. While multiple resonance thermally activated delayed fluorescence emitters offer narrowband emission with reduced excited-state energy, their planar structure, long-lived excitons, and deep highest occupied molecular orbital levels cause detrimental aggregation and instability. Here, we introduce a "3D anchoring" strategy that strategically enhances intramolecular noncovalent interactions. A sterically encumbered, sandwich-like architecture with carbazole-based dual anchors simultaneously suppresses π-π stacking and reinforces bond dissociation energy, boosting intrinsic stability. The proof-of-concept emitters demonstrate bright blue photoluminescence in solution, with photoluminescence quantum yields surpassing 92% and exceptionally narrow emission bands down to 18nm. The corresponding optimized OLED device achieves a maximum external quantum efficiency of 38.2%, alongside record-high current and power efficiencies (59.2cd A- 1 and 66.8lm W- 1, respectively), excellent color purity (CIEy < 0.25), and a 2.3-fold improvement in operational lifetime. This work thereby presents a widely applicable design principle for next-generation high-performance blue emitters.

ABSTRACT Currently, the development of luminescent materials is a major focus of research. In particular, inorganic phosphor‐based compounds have been widely utilized for different types of applications including cathode ray tubes (CRTs), lamp industries; field emission displays (FEDs), radiation dosimetry, and white light emitting diodes (WLEDs). In this research, we successfully synthesized single‐host Ca 14 Zn 6 Al 10 O 35 : Dy 3+ /Sm 3+ by using the wet chemical method to achieve white light emission. XRD analysis confirmed the phase purity of Ca 14 Zn 6 Al 10 O 35 . SEM images showed that the phosphor materials tend to form agglomerates. Photoluminescence (PL) measurements of Ca 14 Zn 6 Al 10 O 35 :Dy 3+ doped phosphors demonstrated efficient excitation at 353 nm, with prominent emission bands at 488 nm (blue) and 575 nm (yellow). Co‐doping with Sm 3+ ionsresulted in strong blue to red emissions. The color qualities of the luminous prepared samples were calculated using the Commission Internationale de l'Eclairage (CIE) coordinates. Therefore, these findings result suggest that Dy 3+ /Sm 3+ co‐doped Ca 14 Zn 6 Al 10 O 35 phosphors, when excited by UV‐LEDs could be suitable for producing white light emitting diodes and display devices.

Broad band emission Cr3+ doped KAlP2O7 phosphor synthesized by simple one-step solid-state reaction for both NIR LED and plant growth LED applications

Far-red phosphors featuring high quantum efficiency and emission bands that strongly overlap with the absorption spectra of plant pigments are crucial for advancing plant cultivation lighting technology. Restricted by the large Stokes shift, far-red phosphors typically exhibit low energy efficiency. Moreover, many far-red phosphors suffer from low quantum efficiency, which has emerged as a critical issue in the research of these materials. To address the issue, conventional strategies-including crystal field engineering, defect engineering, and sensitizer doping-have been widely adopted to enhance their emission intensity. In this work, we propose a novel and effective strategy to improve the emission performance of far-red phosphors: low-melting-point magnesium chloride has been introduced as a flux to regulate the reaction pathway of the composite oxide phosphor Ca14Mg5.94Li0.03In0.03Ga9.95O35:0.05Mn4+ (CMLIGO:0.05Mn4+). The cubic intermediate product with a structure analogous to the target product has been designed to form a compact lattice structure and reduce crystal defects, thereby enhancing the luminescence intensity and quantum efficiency of the phosphor. The Ca14Mg5.94Li0.03In0.03Ga9.95O35:0.05Mn4+@3 wt% MgCl2 (CMLIGO:0.05Mn4+@3 wt% MgCl2) shows a broad excitation band (250-600 nm) and far-red emission centered at 720 nm (650-800 nm). Under 365 nm excitation, the CMLIGO:0.05Mn4+@3 wt% MgCl2 exhibits an internal quantum efficiency of 91.4%. Benefiting from its high internal quantum efficiency and the emission band that matches well with the absorption spectrum of phytochrome in the far-red absorbing form (phytochrome Pfr), CMLIGO:0.05Mn4+@3 wt% MgCl2 demonstrates promising potential for applications in plant cultivation lighting. This work offers a new direction for synthesizing and modification of composite oxide phosphors.