White Light Emissive Eu(III) Complexes through Ligand Engineering and their Applications in Cool Near Ultraviolet White Light Emitting Diodes and Thermometer.

In pursuit of enhancing white light quality for solid-state lighting (SSL) applications, an attempt has been made to design novel imidazo-bipyridyl ligands as an ancillary ligand to obtain multiple emissions (mimic sunlight) in the Eu-complex. By strategically modifying the phenanthroline core with imidazo-bipyridyl incorporation with 1 or 2-Napthyl groups at the C1 position, the excitation spectral line is successfully shifted from Ultraviolet (UV) to near UV/visible spectrum (where the LED emission occurs). The ligands showed greenish blue emission in solid and solution. Density Functional Theory (DFT) calculations were utilized to understand the energy transfer processes from ligand to Eu ion in the Eu complexes. The analysis revealed that the energy transfer is incomplete, primarily attributed to the proximity of triplet state energy levels to the resonance level of Eu(III) ions as reflected in solvatochromism. These complexes exhibit a unique dual emissive behavior (emitting multi-color) including white light across various solvents. These complexes hold great promise as single-component white light-emissive materials, with potential applications in white light-emitting diodes (WLED). The fabricated white LED showed an excellent color rendering index (CRI ~93 %). Beyond lighting, this distinctive property opens avenues for temperature sensing ([Eu(DBM)31-Naph] shows the highest sensitivity of Sr=10.97 %, and [Eu(DBM)32-Naph] shows the highest sensitivity of Sr=5.5 % at 333 K) and vapoluminescent (acid-base on-off-on luminescence) studies. This research pioneers the development of these complexes as potential single-component materials for superior white LEDs, underlining their multifaceted utility in cutting-edge lighting and sensing technologies.

Narrow-Band Red-Emitting Phosphors with High Color Purity, Trifling Thermal and Concentration Quenching for Hybrid White LEDs and Li3Y3BaSr(MoO4)8:Sm3+, Eu3+-Based Deep-Red LEDs for Plant Growth Applications.

Trivalent europium-based monochromatic red light-emitting phosphors are an essential component to realize high-performance smart lighting devices; however, the concentration and thermal quenching restrict their usage. Here, we report a series of efficient Eu3+-substituted Li3Y3BaSr(MoO4)8 red-emitting phosphors based on a stratified scheelite structure with negligible concentration and thermal quenching. All of the host and phosphor compositions crystallize in monoclinic crystal structure (space group C2/c). All of the phosphor compositions produce narrow-band red emission (FWHM ∼6 nm), which is highly apparent to the human eyes, and lead to exceptional chromatic saturation of the red spectral window. Concurrently, detailed investigations were carried out to comprehend the concentration and thermal quenching mechanism. Absolute quantum yields as high as 88.5% were obtained for Li3Y0.3Eu2.7BaSr(MoO4)8 phosphor with virtuous thermal stability (at 400 K, retaining 87% of its emission intensity). The light-emitting diodes were constructed by coupling Li3BaSrY0.3Eu2.7(MoO4)8 red phosphor with a near-UV LED chip (395 nm) operated at 20 mA forward bias, and the hybrid white LED (an organic yellow dye + red Li3Y3BaSr(MoO4)8:Eu3+ phosphor integrated with an NUV LED chip) showed a low CCT (6645 K), high CRI (83) values, and CIE values of x = 0.303; y = 0.368, which indicated that the synthesized phosphors can be a suitable red component for white LEDs. In addition, we have systematically investigated the Sm3+ and Sm3+, Eu3+ activation in Li3Y3BaSr(MoO4)8 to display the latent use of the system in plant growth applications and establish that the phosphor exhibits orange red emission with an intense deep-red emission (645 nm (4G5/2 → 6H9/2)). The phytochrome (Pr) absorption spectrum well matched the fabricated deep-red LED (by integrating a NUV LED + Li3Y3BaSr(MoO4)8:Sm3+ and Eu3+ phosphor) spectral lines.

Novel narrow band red emitters based on mixed metal oxides and their application in hybrid white light-emitting diodes.

A series of high-efficiency narrow band red-emitting La2 M2 O9 :Eu3+ (M = Mo/W) phosphors for white LEDs was synthesized using a conventional solid-state reaction method. All the compositions show absorption in the near ultraviolet (UV) light region due to charge transfer from O to M (M = W and Mo). In order to investigate the luminescence quenching effect, the Eu3+ concentration was varied in the La2 M2 O9 lattice. The tungstate analogue had a quantum yield of 46.5%, whereas the molybdate equivalent had a comparatively subordinate value (15.4%). The phosphor could be competently excited by ~395 or 465 nm photons (could be integrated well with a near-UV or blue LED chip) and showed dominant red emission electric-dipole transition (5 D0 →7 F2 ) with sharp spectral lines due to 4f-4f electronic transition of the Eu3+ ion and potential red-emitting colour converters for white LEDs. The red LED was fabricated by integrating the best phosphor composition with a near-UV LED and a white hybrid LED was fabricated by conjugating with a yellow organic dye and a red phosphor with near-UV LEDs. The white hybrid LED showed an excellent colour rendering index (83%), with CIE colour coordinates (0.313, 0.365) and CCT (6280 K).

Phenanthroimidazole-based chromophores for organic light-emitting diodes: synthesis, photophysical, and theoretical study.

Organic light-emitting diodes (OLED) are gaining attention and making a significant contribution to the area of lighting and displays technology. The synthesis of new materials that can act as a host as well as emissive materials is crucial and efforts have been made in this direction in this research. Here, four star-shaped fluorophores, with a donor-acceptor (D-A) structure and with triphenylamine and phenanthroimidazole groups with different substitutions at the N1 position of the imidazole moiety, were designed and synthesized. Synthesized fluorophores showed sufficient thermal stability (10% Td in the range 230-280°C). Ultraviolet-visible (UV-vis) spectra of the fluorophores showed multiple absorption bands (bands in the UV region, due to π-π* transitions of the conjugated aromatic portion) and all fluorophores showed blue emission in dichloromethane solution. Electrochemical analysis indicated that all fluorophores had excellent oxidation and reduction characteristics. Theoretical calculations were also performed to better understand the structural and electronic properties of the synthesized fluorophores. All fluorophores had higher triplet (T1 ) energy (ranging from 2.49-2.52 eV) than the widely used green (Ir(ppy)3 -2.4 eV) and red (Ir (piq)2 acac - 2.2 eV) dopant materials. These results indicated that these fluorophores would be useful as host materials for efficient green and red phosphorescent OLEDs.

Structural Mimics of Phenyl Pyridine (ppy) - Substituted, Phosphorescent Cyclometalated Homo and Heteroleptic Iridium(III) Complexes for Organic Light Emitting Diodes - An Overview.

Today organic light emitting diodes are a topic of significant academic and industrial research interest. OLED technology is used in commercially available displays, and efforts have been directed to improve this technology. Design and synthesis of phosphorescent based transition metals are capable of harvesting both singlet and triplet excitons and achieve 100 % internal quantum efficiency is an active area of research. Among all the transition metals, iridium is considered a prime candidate for OLEDs due to its prominent photophysical characteristics. In the present review, we have concentrated on the Iridium based homo and heteroleptic complexes that have dissimilar substitutions on phenylpyridine ligands, different ancillary ligands and the effect of substitution on HOMO/LUMO energies and a brief discussion and correlation on the photophysical, electrochemical and device performances of the different complexes have been reviewed for organic light emitting diodes.

Triphenylamine based yellowish-orange light emitting organic dyes (donor-π-acceptor) for hybrid WLEDs and OLEDs: synthesis, characterization and theoretical study.

Six novel yellowish-orange light emitting dye molecules consisting of an electron deficient phenone (acceptor) linked to triphenylamine (donor), were designed and synthesized. The photophysical and electrochemical properties of the dyes were systematically investigated and examined using DFT calculations. All the synthesized dye materials have shown high quantum yields (ranging from 0.35to0.74%). The dyes emitted intense yellowish-orange (x = 0.427, y = 0.481) to orange color (x = 0.511, y = 0.484) with appropriate CIE color coordinates. The synthesised dyes were used for generating white light by fabricating white LEDs. Among all hybrid white LED devices TPA-2 has shown bright white emission with CIE color coordinates x = 0.32, y = 0.33. Theoretical calculations have been performed to explore the optical, electronic, charge transport, and stability properties of the TPA derivatives as charge transport and emissive materials for organic light emitting devices (OLEDs). The results show that, all the derivatives are highly luminescent and their hole transport performances are more favourable than their electron transport performances. So these materials can be used as hole transport materials for OLEDs.

Trivalent rare-earth activated hexagonal lanthanum fluoride (LaF3 :RE3+ , where RE = Tb, Sm, Dy and Tm) nanocrystals: Synthesis and optical properties.

The LaF3 nanocrystals through a facile hydrothermal route with hexagonal structures have been synthesized via doping of trivalent rare earth (RE3+ ) ions - RE = Tb, Sm, Dy and Tm - with rod-like and perforated morphologies using NH4 F as fluorine precursor. Hexagonal phase formation was confirmed by powder X-ray diffraction. The crystalline sizes were calculated by the Scherrer equation where found to have an average crystalline size of 12 to 35 nm. The morphological studies of the nanocrystals were carried out by means of transmission electron microscopy (TEM). The LaF3 :Tm3+ ,Sm3+ ions show the characteristic emission of Tb3+ and Tm3+ respectively. In Sm3+ -doped LaF3 , three prominent emission peaks at 561, 597 and 641 nm were found, which belong to 4 G5/2  â†’ 6 H5/2 , 4 G5/2  â†’ 6 H7/2 (magnetic dipole) and 4 G5/2  â†’ 6 H9/2 (electric dipole) transitions, respectively. The Dy3+ activated LaF3 shows blue and yellow emission and the corresponding CIE color coordinate show white light emission (CCT value 10650 K).

Versatile Luminescent Europium(III)-ß-Diketonate-imidazo-bipyridyl Complexes Intended for White LEDs: A Detailed Photophysical and Theoretical Study.

Three ancillary ligands based on imidazo-bipyridyl with phenyl (Ph), naphthyl (Np), and triphenylamine (TPA) substitution were synthesized and secondhand to formulate the consistent europium(III) ternary complexes using thenoyltrifluoroacetone as an anionic ligand. The complete investigation of spectroscopic, photophysical, and electrochemical properties was carried out. The attained results for all the ancillary ligands and their corresponding Eu complexes were compared with one another. All the Eu complexes reveal a broad excitation band ranging from the near-UV to blue region, along with high intense emission and apposite color purity. To further understand the ligand-to-metal energy transfer (ET) process, the geometry of the ligand was optimized and the energy level location (singlet and triplet) was calculated by using DFT and TD-DFT calculations. On the basis of the theoretical calculation, the ET mechanism was proposed. From PL emission spectra in the solid state, complete ET occurs from Ph, Np based ancillary ligands to the Eu3+ ion, which yields a pure red emission, whereas the TPA functionalized based Eu complex shows incomplete ET. Fortunately, white emission was observed in the TPA based Eu complex in the solid state. The white LED was fabricated by using a white emitting complex integrated with 395 nm emitted LED (InGaN) chips under 20 mA forward-bias current. The excitation source from LED was fully observed by the complex shown for 3Eu and showed yellowish emission in different concentrations (the similar observation also reflected in solid). However, in the case of 1Eu and 2Eu complexes, they showed close to white emission. The Commission International de I'Eclairage (CIE) chromaticity coordinates are close to the National Television Standard Committee standard value for white emission, and in addition, the complex 3Eu coated with the blue LED chip (460 nm) by PMMA (1:10) showed bright white emission with CIE x, y values of 0.30, 0.33, respectively.

Controlled Energy Transfer from a Ligand to an EuIII Ion: A Unique Strategy To Obtain Bright-White-Light Emission and Its Versatile Applications.

A new diphenylamine-functionalized ancillary-ligand-coordinated europium(III) ß-diketonate complex showed incomplete photoexcitation energy transfer from a ligand to a EuIII ion. A solvatochromism study led to a balancing of the primary colors to obtain single-molecule white-light emission. Thermal-sensing analysis of the europium complex was executed. The europium complex, conjugated with a near-UV-light-emitting diode (395 nm), showed appropriate white-light-emission CIE color coordinates (x = 0.34 and y = 0.33) with a 5152 K correlated color temperature.

Unveiling the Versatility of Coumarin-Integrated with Phenanthroline/Thiabendazole-Based EuIII Complexes for Smart LEDs, Vapoluminescence, and Bioimaging Applications.

Narrow band red-emitting phosphors based on organo-Eu(III) complexes prove their energetic features with surprising performance in smart red/white LEDs, sensing, and biological fields. In this report, a series of unique Eu(III) complexes have been synthesized with coumarin integrated with a class of phenanthroline(Phen)/thiabendazole(TBZ) based ancillary ligands and dibenzoyl methane (DBM)/2-theonyl trifluoroacetone (TTA) as an anionic ligand. The computational study reveals that the TBZ/Phen-based neutral ligands are superior energy harvesters to those other reported analogue neutral ligands. All the Eu-complexes demonstrated outstanding red emission due to electric dipole (ED) transition (5D0 → 7F2) in solid, solution, and thin film with high quantum yield (QY). Theoretical analysis (TD-DFT) and experimental findings describe that the energy transfer (ET) from the ligand's triplet level to the Eu(III) ion is completely occurring. The Eu(III) complexes can potentially be used to fabricate intense hybrid white and red LEDs. All of the fabricated red LEDs revealed high luminous efficiency of radiation (LER) values. The fabricated blue LED based hybrid white LEDs displayed remarkable performance with a low correlated color temperature (5634 K), high color rendering index 88%, and CIE values (x = 0.33; y = 0.342) for 3Eu. By interaction with acid-base vapors, Eu-complexes displayed effectively alterable on-off-on luminescence. Further, cellular imaging shows that Eu-complexes can be a potential biomarker for cancer cell lines.

Effect of cimetidine, a model drug for inhibition of the organic cation transport (OCT2/MATE1) in the kidney, on the pharmacokinetics of glycopyrronium.

OBJECTIVE: Glycopyrronium (NVA237), a novel once-daily long-acting muscarinic antagonist (LAMA), has recently been approved for maintenance treatment of COPD. This study evaluated the effect of organic cation transporter inhibition on inhaled glycopyrronium disposition using cimetidine as a probe inhibitor. METHODS: In this open-label, two-period, two-sequence, crossover study, 20 healthy subjects received two treatments. A single dose of 100 µg glycopyrronium was inhaled alone and on Day 4 of a 6-day treatment with oral cimetidine 800 mg b.i.d. Trough plasma concentrations of cimetidine were determined throughout cimetidine dosing. Plasma concentrations and urinary excretion of glycopyrronium were determined up to 72 hours post glycopyrronium dose. The primary pharmacokinetics (PK) parameters were plasma peak concentration (Cmax), AUC up to the last measured concentration (AUClast), and renal clearance (CLr) of glycopyrronium. RESULTS: Cimetidine trough concentrations indicated that PK steady state of cimetidine was reached prior to single dose inhalation of glycopyrronium. Inhalation of glycopyrronium in the presence of cimetidine resulted in an increase in total systemic exposure (AUClast) of glycopyrronium by 22% (geometric mean ratio 1.22; 90% CI: 1.12 - 1.32). This exposure increase correlated with a slight decrease of 23% in CLr (geometric mean ratio 0.77; 90% CI: 0.70 - 0.85). Cmax was not affected. Both treatments were safe and well tolerated without any deaths or severe adverse events. CONCLUSION: Based on the magnitude of the PK changes seen in this study, no relevant drug interaction is expected when glycopyrronium is co-administered with cimetidine or other inhibitors of the organic cation transport.

Narrow-band dazzling red-emitting (LiCaLa(MoO4)3:Eu3+) phosphor with scheelite structure for hybrid white LEDs and LiCaLa(MoO4)3:Sm3+,Eu3+-based deep-red LEDs for plant growth applications.

Presently, the preparation of dazzling narrow-band red-emitting phosphors for solid-state lighting is still a challenge. In this context, herein, a series of pure narrow-band red-emitting LiCaLa1-xEux(MoO4)3 phosphors was synthesized and characterized, and their spectroscopic properties were systematically studied. In addition, a series of orange-red-emitting LiCaLa1-ySmy(MoO4)3 phosphors with the simultaneous doping of Eu3+ was synthesized for plant growth applications. The optical studies revealed that the phosphors showed pure red emission with a full width at half maximum of ∼5 nm and 97% color purity. Alternatively, their absorption spectrum showed good absorption strength in the near UV to blue region. Non-concentration quenching behavior was observed even when the concentration of Eu3+ in the lattice was 100%. The dominant electric dipole transition in the emission spectrum indicated that the Eu3+ ion occupies a non-centrosymmetric site in the lattice. At 150 °C, the phosphor retained 88.83% of its emission intensity calculated at room temperature. Thus, it can be useful for the fabrication of LEDs. Subsequently, Eu-rich red and white LEDs (integrated with yellow phosphor) were fabricated with near-UV and blue LED chips, respectively. The fabricated hybrid white LED showed pure white emission with a CCT of 4762 K, CRI of 81%, and close CIE coordinates of (0.34, 0.33). The absolute quantum yield for the fully substituted LiCaEu(MoO4)3 composition was calculated to be 44.50% upon excitation at 395 nm. To utilize LED light for plant growth applications, efforts were made to synthesize orange-red (Sm3+) and deep-red (Sm3+, Eu3+) phosphors and utilize the simultaneously doped phosphor for the fabrication of deep-red LEDs. The spectral lines well-matched the spectrum of phytochrome (Pr). Thus, the phosphor in the present study is a potential candidate as a red and deep-red phosphor for the fabrication of hybrid white LEDs and deep-red LEDs (for plant growth purposes), respectively.

Recent progress in trivalent europium (Eu3+)-based inorganic phosphors for solid-state lighting: an overview.

Narrow band red-emitting phosphors are significant constituents but still a bottleneck for next-generation smart displays and high-performance lighting (solid-state lighting based white light-emitting diodes (WLEDs)) technology. This review emphasizes the fundamental understanding and comprehensive overview of the recent progress and challenges associated with inorganic phosphors or down (wavelength) convertors, providing special attention to narrowband red-emitting oxide phosphors for phosphor-converted WLEDs (pc-WLEDs). In this context, the comprehensive progress on trivalent europium (Eu3+, in scheelite and double perovskite structures) based oxide phosphors with special emphasis on structure-composition-property-correlations is briefly reviewed. Furthermore, the challenges faced in the design of new oxide red phosphors and strategies to improve their absorption, emission efficiency, and future research direction are highlighted.

REcovery and SURvival of patients with moderate to severe acute REspiratory distress syndrome (ARDS) due to COVID-19: a multicenter, single-arm, Phase IV itolizumab Trial: RESURRECT.

BACKGROUND: Itolizumab, an anti-CD6 monoclonal antibody, down-regulates COVID-19-mediated inflammation and the acute effects of cytokine release syndrome. This study aimed to evaluate the safety and efficacy of itolizumab in hospitalized COVID-19 patients with PaO2/FiO2 ratio (PFR) ≤200 requiring oxygen therapy. RESEARCH DESIGN AND METHODS: This multicenter, single-arm, Phase 4 study enrolled 300 hospitalized adults with SARS-CoV-2 infection, PFR ≤200, oxygen saturation ≤94%, and ≥1 elevated inflammatory markers from 17 COVID-19 specific tertiary Indian hospitals. Patients received 1.6 mg/kg of itolizumab infusion, were assessed for 1 month, and followed-up to Day 90. Primary outcome measures included incidence of severe acute infusion-related reactions (IRRs) (≥Grade-3) and mortality rate at 1 month. RESULTS: Incidence of severe acute IRRs was 1.3% and mortality rate at 1 month was 6.7% (n = 20/300). Mortality rate at Day 90 was 8.0% (n = 24/300). By Day 7, most patients had stable/improved SpO2 without increasing FiO2 and by Day 30, 91.7% patients were off oxygen therapy. Overall, 63 and 10 patients, respectively, reported 123 and 11 treatment-emergent adverse events up to Days 30 and 90. No deaths were attributable to itolizumab. Patient-reported outcomes showed gradual and significant improvement for all five dimensions on EQ-5D-5L. CONCLUSION: Itolizumab demonstrated acceptable safety with a favorable prognosis in hospitalized COVID-19 patients. CLINICAL TRIAL REGISTRATION: CTRI/2020/09/027941 (Clinical Trials Registry of India).

Stable and efficient narrow-band red emitters with high colour purity for white LEDs and plant growth applications.

The search for extremely narrow-band new red emitters is essential for smart displays and lighting applications. Herein, we report the synthesis of a series of red-emitting Eu3+-substituted Li3BaSrY3(WO4)8 and solid-solution (Li3BaSrY0.3Eu2.7(WO4)8-y(MoO4)y) phosphors with a stratified scheelite structure and the systematic investigation of their optical properties. All the compositions show broad absorption (charge transfer (O2- → M6+)) extended up to the blue region along with strong characteristic Eu3+ excitation lines. The phosphor compositions exhibit proficient narrow-band red emission (quantum yield up to 85%; full width at half maximum (FWHM) = 6 nm; CIE colour coordinates x = 0.65, y = 0.35, i.e. approaching the NTSC standard for red colour) of exceptional colour purity (94% to 98%), and this host supports heavy trivalent Eu activation (showing zero concentration quenching of the emission (Eu-rich lattice)). The dominating electric dipole (5D0 → 7F2, red emission) transition shows Eu3+-ion occupancy in the non-centrosymmetric site in the host lattice. The selected composition shows better absolute quantum efficiencies compared to commercial phosphors. The presently synthesized phosphors have proven to be thermally stable against the temperature quenching effect. The fabricated red LED showed excellent performance, colour purity, LER and CIE values. The excellent optical properties, quantum yield and thermal stability make the phosphor applicable as a red component in solid-state lighting devices and as a light source for plant growth applications.

Efficient and ultra-thermally stable Eu3+ and Sm3+-activated narrow-band red/deep red-emitting phosphors and their versatile applications.

A succession of Eu3+-activated Na2Y4(WO4)7 (NYW) red phosphors were synthesised and their optical properties were studied in detail for white LED, latent fingerprint and plant growth applications. The phosphors crystallised in a tetragonal system with space group I41/a. The NYW:Eu3+ red phosphors demonstrated a line-like emission at 616 nm owing to electric dipole transition, and a systematic concentration-dependent PL study revealed that concentration quenching occurs at x = 1.8 with a color purity of 96.06%. The thermal stability and internal quantum efficiency of the phosphor were found to be ∼75.54% (at 423 K) and 88%, respectively. Furthermore, solid solution phosphors were synthesized to increase QE, which was found to be 91.27%. Specifically, the hybrid white LED exhibits warm white light with high CRI (80) and low CCT (5730 K) values, and these values are further improved (CRI-81, CCT-4274 K) when the WLED is fabricated using the most efficient solid solution phosphor Na2Y2.2Eu1.8(WO4)3(MoO4)4. The currently synthesized phosphors can be potential candidates for security applications. The selected phosphor compositions can be used for the detection of latent fingerprints. Besides, a succession of Eu3+ and Sm3+ co-doped phosphors were synthesized and their photophysical properties were studied systematically. The deep red LED was fabricated using the same and this could be a possible light source for plant growth usage.

Narrow-band red-emitting phosphor with negligible concentration quenching for hybrid white LEDs and plant growth applications.

Narrow-band red-emitters are the key to solving problems encountered by the current white LED technology. In this context, a series of new red-emitting Li3BaSrLa3(MoO4)8:Eu3+ phosphors were synthesized and characterized through various spectroscopic methods. All phosphor compositions were crystallized in the monoclinic phase, with space group C2/c. A broad charge transfer (O2-→ Mo6+) extended up to the blue region along with strong 7F0→5L6, 5D3 absorption, making them looked-for materials for warm white LED applications. The concentration quenching study reveals that there was no concentration-quenching occuring and the quantum yield of this non-concentration-quenching Li3BaSrLa0.3Eu2.7(MoO4)8 phosphor reaches 92.6%. The Li3BaSrLa0.3Eu2.7(MoO4)8 retain >80% of its emission intensity at 150 °C. The best red-emitting composition was integrated with near UV LED and obtained bright red emission with CIE x = 0.6647, y = 0.3357. White LED was fabricated by integrating the blue LED with yellow dye + red phosphor and white LED showed bright white light with CCT (5546 K), CIE (0.331, 0.385), and CRI (81%). In addition, the red LED spectrum is well-matched with the phytochrome (Pr) absorption spectrum and is useful for plant growth applications.

A two-arm, randomized, controlled, multi-centric, open-label phase-2 study to evaluate the efficacy and safety of Itolizumab in moderate to severe ARDS patients due to COVID-19.

Objective: Efficacy and safety of Itolizumab, an immunomodulatory mAb, in treating moderate-to-severe acute respiratory distress syndrome (ARDS) due to cytokine release in COVID-19 patients was evaluated in a multi-centric, open-label, two-arm, controlled, randomized, phase-2 study.Methods: Patients were randomized (2:1) to Arm-A (best supportive care [BSC]+Itolizumab) and Arm-B (BSC). Primary outcome of interest was reduction in mortality 30-days after enrollment.Results: Thirty-six patients were screened, five treated as first-dose-sentinels and rest randomized, while four patients were screen-failures. Two patients in Arm-A discontinued prior to receiving one complete infusion and were replaced. At end of 1-month, there were three deaths in Arm-B, and none in Arm-A (p = 0.0296; 95% CI = -0.3 [-0.61, -0.08]). At end of study, more patients in Arm-A had improved SpO2 without increasing FiO2 (p = 0.0296), improved PaO2 (p = 0.0296), and reduction in IL-6 (43 vs 212 pg/ml; p = 0.0296) and tumor necrotic factor-α (9 vs 39 pg/ml; p = 0.0253) levels. Transient lymphopenia (Arm-A: 11 patients) and infusion reactions (7 patients) were commonly reported treatment-related safety events.Conclusion: Itolizumab is a promising, safe and effective immunomodulatory therapy for treatment of ARDS due to cytokine release in COVID-19 patients, with survival and recovery-benefit.

Narrow band red emitting europium complexes and their application in smart white LEDs and vapoluminescent sensors.

Narrow band red emitting phosphors play a vital role in high performance smart white LEDs. In this context, a series of new Eu(iii) complexes have been synthesized with neutral ligands (C1-functionalised phenanthro-imidazole-based ancillary ligands substituted with phenyl moieties (m-CF3, p-CF3, p-CH3 and 1-naphthyl and 2-naphthyl group)) and dibenzoylmethane (DBM) as an anionic ligand. All the newly synthesized Eu-complexes showed extremely narrow band red emission due to the electric dipole transition (5D0-7F2, both in solid and thin film) with high quantum efficiency. A combined experimental and theoretical study indicates that the energy transfer from the ligand to the metal ion is complete. A temperature dependent photoluminescence (PL) study in solution reveals that the red emission is retained (only the ED (5D0-7F2) intensity decreases with increasing temperature). Red LEDs and hybrid white LEDs were fabricated by using a near UV LED chip with europium complexes and a near UV/blue LED conjugated with a yellow organic dye and europium complex mixture, respectively. Hybrid white LEDs (Eu(DBM)3Phen-pCN-pCF3 + yellow organic dye) showed superior CRI (84%) and CIE (x = 0.36, y = 0.39) values (near UV based) and CRI (82%) and CIE (x = 0.34, y = 0.36) values (blue LED based). In addition, the studied Eu-complexes herein showed excellent reversible on-off-on luminescence behavior with exposure to acid-base vapours. Detailed spectroscopic investigation reveals that the protonation of the Eu-complexes (ligands) plays a key role in the on-off-on luminescence.

Zero-concentration quenching: a novel Eu3+ based red phosphor with non-layered crystal structure for white LEDs and NaSrY(MoO4)3:Sm3+ based deep-red LEDs for plant growth.

Oxide based highly efficient narrow band red emitting phosphors are still a bottleneck in white LED applications. Trivalent europium ion based phosphors could be a better choice, however their weak oscillator strength restricts their use in white light emitting diodes (LEDs). Herein, we report a novel red emitting NaSrEu(MoO4)3 (NSEuM) phosphor with zero concentration quenching (non-layered crystal structure). The phosphors (NaSrY1-xEux(MoO4)3, x = 0.1-1, in increments of 0.1) were synthesized through a traditional solid-state reaction and their phase formations were analyzed by powder X-ray diffraction (PXRD) followed by Rietveld refinement. Under 395 nm excitation, all the phosphors showed sharp emission at 616 nm (full width at half maximum, FWHM ∼4-5 nm) owing to the 5D0→7F2 electric dipole transition of the Eu3+ ion. A concentration dependent photoluminescence (PL) study revealed that there is no concentration quenching of the systems, leading to them having superior emission characteristics over those of commercial red phosphors as well as a reported Eu3+ phosphor with a layered structure. The color purity of the synthesized phosphor was observed to be 96.32% and it shows excellent thermal stability at 423 K, retaining 64.6% of the emission intensity of its initial room temperature. The NSEuM phosphor shows a high absolute quantum yield of 79.7%. Besides this, a red LED (near UV (NUV) LED chip with the NaSrEu(MoO4)3 phosphor) as well as a hybrid white LED (NUV LED chip with an organic yellow dye + red NSEuM phosphor) were fabricated and their optical properties were studied. After the inclusion of the red phosphor in the hybrid white LED, the color rendering index (CRI)/correlated color temperature (CCT) were improved significantly (60/9333 K vs. 79/6004 K, respectively). In addition, to show the potential use of the system in plant growth application, we systematically investigated the Sm3+ activation in NaSrY(MoO4)3 and found that the phosphor shows orange red emission with an intense deep red emission (645 nm (4G5/2→6H9/2)). We fabricated a hybrid red/deep red LED by integrating a NUV LED with a mixed Sm3+ and Eu3+ phosphor and the spectral lines were well matched with the phytochrome (Pr) absorption spectrum. The presently investigated phosphor showed potential in a white LED as well as a deep red/orange-red LED for plant growth.