Commission Internationale Research Articles

Post-cure Heat Treatments Influence the Mechanical and Optical Properties of Acrylic and Bis-acryl Composite Resins.

To evaluate the influence of post-cure heat treatments (PCHT) on Knoop microhardness (KHN) and color change of bis-acryl composite resin (Protemp 4 - 3M ESPE, USA and PrimmaArt - FGM, Brazil) and chemically activated acrylic resins (Dencôr - Clássico, Brazil, and Duralay - Cotia, Brazil). Specimens (12×1 mm) were prepared for each material (n=10/group). Thirty minutes after curing, the specimens were subjected to PCHT for 10 minutes at 70°, 100°, or 130°C. The control group was kept at room temperature (24°C) for the same amount of time. KHN was analyzed 24 hours after PCHT (n=10). Following Commission Internationale de l'Éclairage (CIE) Delta E 2000 (CIEDE2000 [ΔE00]), color measurements were obtained at three time points: 1. after polymerization; 2. after PCHT; and 3. after 30 days of storage in water, coffee, or red wine. Data for each material were analyzed by one-way analysis of variance (ANOVA) (p<0.05). The PCHT at 130°C produced the highest KHN values. Except for the 70°C groups from Dencôr and Protemp, all PCHTs increased the initial color values (p>0.05). In general, chemically activated acrylic resins showed an increase in color stability when subjected to PCHT (p>0.05). For bis-acryl composite resin, PCHT did not influence color stability (p<0.05). Overall, the results showed that PCHT increased the tested materials' color changes and Knoop microhardness. However, except for PCHT at 130°C in Duralay, the color changes remained within acceptable values. The PCHT treatment resulted in better color stability for most of the composite resins studied.

Donor engineering to regulate fluorescence of a symmetrical structure based on a fluorene bridge for white light emission.

A white organic light-emitting device (WOLED) obtained using blue and yellow complementary colors possesses extremely high optical efficiency. We designed and prepared a completely symmetric D-π-D type efficient blue light small molecule FFA based on octylfluorene as a π bridge, where the undoped device showed efficient blue organic light-emitting device (OLED) performance with a maximum emission wavelength of 428 nm, Commission Internationale de l'Eclairage (CIE) coordinates of (0.17, 0.11) and one of the narrowest full width at half maximum (FWHM) of 35 nm. To improve the matching measure of complementary color materials for achieving white light emission, a yellow light small molecule FCzA was prepared by adjusting the conjugation degree of peripheral electron-donating groups based on the same fluorene-based π bridge with FFA. Undoped devices based on FCzA demonstrated an electroluminescence (EL) emission peak at 576 nm with CIE coordinates of (0.43, 0.49) and a relatively wide FWHM of 130 nm. Ultimately, the white OLED device was modulated with CIE coordinates located at (0.33, 0.38) via proportional regulation with a mixture of FFA and FCzA in a ratio of 10 : 3 as the light-emitting layer.

A terpyridyl-imidazole based europium tris-(β-diketonate) complex as an efficient molecular luminescent thermometer and single component white light emitter via synergy in energy transfer between ligands and Eu3.

The thermosensing and thermochromic behavior of one of our recently reported terpyridyl-imidazole based ternary europium tris-(β-diketonate) complexes of the composition [Eu(tta)3(tpy-HImzphen)] (tta = 2-thenoyltrifluoroacetone and tpy-HImzphen = 2-(4-[2,2':6',2''] terpyridin-4'-yl-phenyl)-1H-phenanthro[9,10-d]imidazole) has been thoroughly investigated in this work. The said Eu(III) complex exhibits magnificent thermosensing as well as thermochromic properties and can be recommended as an excellent temperature sensor in a wide temperature domain of 273-343 K in terms of both emission intensity ratio (Sm = 5.78% K-1 at Tm = 343 K, δT = 0.012 K) and lifetime values (Sm = 3.36% K-1 at Tm = 333 K, δT = 0.009 K) or even in terms of its emitting color (red at 268 K, violet at 303 K, and blue at 343 K). Additionally, it displays remarkable solvent-induced luminescence behavior by displaying various emitting colors instead of its sole characteristic red emission upon varying the nature of the solvent. Finally, amalgamating these two features, we are able to attain white light emission (Commission Internationale de l'Eclairage coordinates: x = 0.34, y = 0.38) at 283 K from a single component. A plausible energy transfer mechanism has also been proposed in light of the existence of the ligand-to-metal charge transfer (LMCT) state as the quencher.

Colorimetria e propriedades químicas da madeira de Parkia pendula e Simarouba amara modificada termicamente

ABSTRACT The thermal modification of wood is a process that alters its chemical composition, aiming to improve technological properties such as dimensional stability, reduction of equilibrium moisture content, homogeneity, or color. In this context, this study aimed to evaluate the colorimetry and chemical properties of the wood of Parkia pendula (angelim-saia) and Simarouba amara (marupá) that was thermally modified by different methods. Three treatments were evaluated: T1 (pre-treatment in an oven for one hour at 120 °C and treatment in an oven at 180 °C for three hours); T2 (pre-treatment in an autoclave at 125 °C for three hours under 1.2 kgf cm-2 and treatment in an oven at 180 °C for three hours); and T3 (without pre-treatment, with sample treatment in vegetable oil). The thermally modified wood was evaluated in relation to untreated wood for structural chemical composition (extractives, lignin, holocellulose and ash content), colorimetric parameters defined through the CIELAB (Commission Internationale de l´Eclairage) system and total color variation. We detected a significant increase in extractives content and a decrease in holocellulose and lignin content in T3 for both species, which can be explained by the impregnation of oil in the wood samples. The thermal modification caused the surface darkening of the wood of both species, which was more pronounced in P. pendula. Despite the colorimetric change, there was no chemical damage to the wood.

A record-high EQE of 7.65%@3300 cd m-2 achieved in non-doped near-ultraviolet OLEDs based on novel D'-D-A type bipolar fluorophores upon molecular configuration engineering.

Developing a high-performance near-ultraviolet (NUV) material and its simple non-doped device with a small efficiency roll-off and good color purity is a promising but challenging task. Here, we proposed a novel donor'-donor-acceptor (D'-D-A) type molecular strategy to largely solve the intrinsic contradictions among wide-bandgap NUV emission, fluorescence efficiency, carrier injection and transport. An efficient NUV fluorophore, 3,6-mPPICNC3, exhibiting a hybridized local and charge-transfer state, is achieved through precise molecular configuration engineering, realizing similar hole and electron mobilities at both low and high electric fields. Moreover, the planarized intramolecular charge transfer excited state and steric hindrance effect endow 3,6-mPPICNC3 with a considerable luminous efficiency and good color purity in the aggregation state. Consequently, the non-doped device emitting stable NUV light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.160, 0.032) and a narrow full width at half maximum of 44 nm exhibits a state-of-the-art external quantum efficiency (EQE) of 7.67% and negligible efficiency roll-off over a luminance range from 0 to 3300 cd m-2. This is a record-high efficiency among all the reported non-doped NUV devices. Amazingly, an EQE of 7.85% and CIE coordinates of (0.161, 0.025) are achieved in the doped device. This demonstrates that the D'-D-A-type molecular structure has great potential for developing high-performance organic light-emitting materials and their optoelectronic applications.

Synthesis and photoluminescence properties of high-quality reddish-orange emitting Ca4Nb2O9:Eu3+ phosphors for WLEDs and anti-counterfeiting.

In this report, we successfully synthesized a novel trivalent europium (Eu3+)-activated Ca4Nb2O9 phosphor emitting reddish-orange light via its 5D0 → 7F1 and 5D0 → 7F2 transitions. In the Ca4Nb2O9 host, Eu3+ ions exhibited optimal doping at a concentration of 15 mol%, with the concentration-quenching mechanism predominantly driven by electric dipole-dipole interactions. In addition, the Ca4Nb2O9:Eu3+ phosphor exhibited excellent thermal stability with a photoluminescence (PL) intensity of 71.6% at a working temperature of 423 K. Interestingly, the internal PL quantum yield (PLQY) of the optimal sample was obtained to be 87.43%, and the external PLQY was determined to be 47.81%. The fabricated white light-emitting diode that employed this optimized phosphor alongside commercial phosphors, via a novel silica epoxy gel (parts A and B)-based method, exhibited good color rendering index (color rendering index = 80.65), excellent warm-correlated color temperature (correlated color temperature = 3753 K), and Commission International de l'Eclairage chromaticity coordinate (0.3922, 0.3845). Moreover, the optimal phosphor was introduced into the polyvinyl alcohol (PVA) polymer film, creating a translucent film. These films were then fabricated on glass, plastic, and card, which showed a satisfying emission under ultraviolet radiation. Consequently, the proposed Eu3+-activated Ca4Nb2O9 phosphors can be used as light sources and the Ca4Nb2O9:Eu3+-PVA film is proposed for anti-counterfeiting applications.

Efficient solution-processed fluorescent OLEDs realized by removing charge trapping emission loss of BODIPY fluorochrome.

The thermally activated delayed fluorescence (TADF)-sensitized fluorescent (TSF) dye strategy has been used successfully in thermally evaporated organic light-emitting diodes (eOLEDs), but the development of solution-processed TSF-OLEDs (TSF-sOLEDs) is still very limited to date. Previously, the introduction of electronically inert shielding terminal groups for TADF sensitizer and/or fluorescent dyes was commonly used in TSF-sOLEDs, which aimed to achieve sufficient Förster energy transfer (FET) while restraining notorious Dexter energy transfer (DET) at a high doping concentration of fluorescent dyes. However, this approach has not yet enabled efficient TSF-sOLEDs owing to severe charge trapping emission (CTE) for triplet loss. In this study, by simply utilizing highly efficient boron-dipyrromethene derivatives (BODIPYs) that simultaneously feature high fluorescent quantum efficiency and narrow-band emission spectra, we developed highly efficient and super color-purity TSF-sOLEDs using a 0.1 wt% ultralow doping strategy. As confirmed, the resultant ultralow doping TSF-sOLEDs achieved sufficient FET from sensitizer to fluorochrome without noticeable CTE issues. The device achieves record maximum external quantum efficiency (EQEmax) and current efficiency (CEmax) of 21.5% and 78.8 cd A-1, respectively, and an ultrapure green emission with Commission International de l'Eclairage (CIE) coordinates of (0.28, 0.65). This study validates the new device architecture of ultralow doping TSF-sOLEDs, which paves the way for future development of high-resolution TSF-sOLED displays via a simple solution-processed manufacturing approach.

Synthesis and Structural Features of Tunable Emitting Single- Phased Eu3+/ Tb3+ Co- Doped LaAlO3 Nanophosphors

In the prevailing study, single- phased color- tunable La1-x-yEuxTbyAlO3 co- doped nanocrystalline phosphors have been synthesized via the most simplistic and low cost urea- aided solution combustion synthetic route. This was done by adjusting the doping concentration of Eu3+ (x = 0.01, 0.03, 0.05, 0.07 mol) and Tb3+ (y = 0.03 mol) ions in the LaAlO3 host lattice. The X- ray powder diffraction (XRD) and Rietveld refinement analysis confirmed the formation of single- phased La0.97-xAlO3: xEu3+/ 0.03Tb3+ (x = 0.07), co- doped nanophosphor at 800°C. The synthesized nanophosphors were crystallized in cubic crystal system having Pm3̄m space group with 221 space group number. The morphological studies i.e., field emission scanning electron microscopy (FE- SEM), and transmission electron microscope (TEM) images depicted the agglomerated clusters of distinct spherical shaped particles of La0.97-xAlO3: xEu3+/ 0.03Tb3+ in nano- regime. Energy dispersive X- ray analysis (EDAX) was employed to ascertain the real elemental mapping of the fabricated phosphors. Through diffuse reflectance (DR) spectroscopy measurements, the optical band gap value for La0.92Eu0.05Tb0.03AlO3 nanocrystalline phosphor was determined to be 5.26 eV. The photoluminescent excitation (PLE) and photoluminescent emission (PL) spectra were studied in detail as a function of Eu3+ ion contents and La1-x-0.03AlO3: xEu3+/ 0.03Tb3+ (x = 0.05 mol) co- doped sample exhibits strongest emission and over the 0.05 Eu3+ ions doping concentration, the emission intensity falls as a consequence of the quenching phenomenon. The concentration quenching in directed co- doped nanophosphors was attributed to the dipole - dipole interactions. With the exploitation of photoluminescent data, Commission International de I'Eclairage 1931 (CIE) color coordinates (x, y) of co- doped samples have been calculated from the emission spectra, which revealed the color could be tuned i.e., from orange to red region in La0.97-xAlO3: xEu3+/ 0.03Tb3+ samples with divergences in the Eu3+ and other significant photometric assets viz. correlated color temperature (CCT), color purity (CP) of the synthesized La1-x-yAlO3: xEu3+, yTb3+ co- doped nanocrystalline photoluminescent materials were also determined. The studies outcomes suggested that Eu3+/ Tb3+ co- doped LaAlO3 phosphors have great potential as color- tunable luminescent material in solid- state lighting and display technologies.

CsZnPbBr3/ZnS core/shell perovskite nanocrystals for stable and efficient white light-emitting diodes.

The widespread applicability of perovskite nanocrystals (PeNCs) is impeded by their intrinsic instability. A promising solution is utilizing robust chalcogenides as a protective shell to shield the sensitive luminescent cores from the external environment. However, the inferior structural stability and surface lability of PeNCs usually lead to perovskite phase transition during shell growth. Herein, we introduced smaller Zn ions to partially replace Pb ions in perovskites, which reduces the Pb-X bond length and enhances the Pb-X bond energy for inner lattice stabilization. Simultaneously, extra oleylammonium bromide (OAmBr) was added to protect the labile surface of PeNCs by compensating for the detachment of ligands and the loss of surface Br ions. As a result, the dual strategies enable the epitaxial growth of a ZnS shell and significantly enhance the chemical stability of CsZnPbBr3/ZnS core/shell PeNCs. After three thermal cycles ranging from 300 to 450 K, the core/shell PeNCs retained 70% of their initial photoluminescence (PL) intensity. In stark contrast, the pristine CsPbBr3 PeNCs exhibit complete PL quenching after just the first temperature cycle. For practical applications, the green core/shell PeNCs were integrated with commercially available red-emitting phosphors on a blue-emitting InGaN chip to fabricate a white light-emitting diode (WLED), which demonstrates a high luminous efficacy (LE) of 61.3 lm W-1 and nearly constant Commission Internationale de l'Eclairage (CIE) coordinates under varying operating currents.

Defect Induced high-color-rendering white light emissions from Ag-doped ZnO

It is crucial to find high-quality white-light phosphors that are simple to synthesize in order to create efficient lighting. In this pursuit, the focus has been on achieving the emission of white light in ZnO and Ag-doped ZnO emerging as a promising phosphor candidate. The optimized ZnO nano phosphors demonstrated visible-light emission with ideal Commission international de I E “Eclairage frequently abbreviated as coordinates (x = 0.33, y = 0.33 ) and a correlated color temperature of 6200 K, and a color rendering index of 100 for equivalent to day white light. Furthermore, under certain ideal processing conditions, neutral white-light emission (x = 0.33, y = 0.33 at λex = 280 and 370 nm) with a Color correlated temperature (CCT) of 5500 K(approx.) was achieved. The Color Rendering Index (CRI) of the ZnO and Ag:ZnO nanoparticles exceeded 90, with high values approaching 96%, which is necessary for accurately portraying object colors in comparison to natural sunshine. The research findings revealed a decrease in the FS emission intensity with all the UV excitation when Ag doped in ZnO, which aligns well with the principles of Stern-Volmer quenching. A reduction in intensity was observed which may be due to the Ag dopant interacting with the luminescent nanoparticles and causing a reduction in their emitted light. The study successfully develops and optimizes ZnO-based nano phosphors with tailored white-light emission characteristics, presenting a promising solution for achieving energy-efficient and high-quality white-light sources for various lighting applications.

The Saudi Central Board for Accreditation of Healthcare Institutions (CBAHI) compared with the Joint Commission International (JCI) and the American College of Radiology (ACR)

In this paper we compare the Saudi Central Board for Accreditation of Healthcare Institutions (CBAHI) with the Joint Commission International (JCI) and the American College of Radiology (ACR) regarding accreditation of hospitals or radiology departments. CBAHI was established in 2005 by the Saudi Arabian Ministry of Health to improve the health care service to the public and to localize the protocols and the policies. CBAHI sets standards for healthcare facilities like hospitals, clinics, and laboratories according to CBAHI standards. The applying of these standards vary on the degree of enforcement of these standards in private or governmental sectors.

Structural, optical and photoluminescence properties of BaLa2ZnO5: Eu3+ phosphor: A prospective red-emitting phosphor for LED applications

Herein, we report the synthesis of red-emitting Eu3+-activated BaLa2ZnO5 phosphors using a high-temperature solid-state reaction technique. The phase confirmation and crystal structure were established through X-ray powder diffraction patterns. Density-functional theory calculations revealed an indirect bandgap in the material. The bandgaps of both undoped and doped BaLa2ZnO5 phosphors were analyzed using diffuse reflectance spectra. The influence of Eu3+ doping on the bandgap was confirmed by applying the Kubelka-Munk function to the diffuse reflectance spectra. The effects of doping on the surface morphology and elemental composition were investigated through field emission scanning electron microscopy and energy-dispersive spectroscopy, respectively. Additionally, X-ray photoelectron spectroscopic studies were conducted to analyze the electronic structure, chemical states and impact of doping on the crystal structure. Using near ultraviolet excitation at 329 nm, the synthesized phosphor exhibited strong red emission attributed to various 5D0 → 7FJ transitions. Concentration quenching phenomena were observed due to dipole-dipole interactions. Judd-Ofelt analysis was performed to elucidate the coordination nature of the doping element in the host lattice. Excellent thermal stability was observed with an activation energy of 0.64 eV for discharging via lattice vibrations. The better color purity (98–99.3 %) and stable Commission Internationale de l’Elcairage coordinates in the red region of the gamut suggest that the prepared phosphor material holds potential as an efficient candidate for ultra violet and blue light-emitting diode chips, as well as an efficient component in the fabrication of white light-emitting diodes.

Influence of Composition and Thickness on The Color and Translucency of Glass-Ceramic Materials for Laminate Veneer Restorations: An In Vitro study

Statement of the problem: Numerous glass-ceramic materials are commercially available, yet achieving optimal esthetic results relies significantly on material composition and thickness. The selection of suitable material and thickness poses an ongoing challenge in clinical practice. Objective: This study aimed to investigate the effect of the composition and thickness of different glass-ceramic materials on the Commission Internationale de l'éclairage (CIE) L*, a*, and b* color coordinates and the translucency parameter (TP00). Materials &amp; Methods: Glass-ceramic blocks of A2 shade, with low translucency, encompassing feldspathic (FS), leucite-reinforced feldspathic (LR), and lithium-disilicate (LD) compositions, were sectioned into three thicknesses: 0.5 mm, 0.7 mm, and 1 mm (n=10). All specimens were polished with ceramic polishing rubbers. Using a spectrophotometer, the CIE L*, a*, and b* color coordinates of the specimens were measured over gray, white, and black backgrounds. The TP00 was calculated using the CIEDE2000 color difference formula. The CIE L*, a*, b*, and TP00 were analyzed using two-way ANOVA and Tukey HSD post-hoc tests (α=0.05). Results: Material, thickness, and their interaction significantly influenced the CIE L*, a*, b*, and TP00 values (P&lt;0.001). The LR group displayed the highest L* and a* values, while the LD group showed the lowest (P&lt;0.001). Conversely, the LD group exhibited the highest b* value (P&lt;0.001). Lightness was lowest in 0.5 mm-thick specimens (P&lt;0.001) and similar for 0.7 mm-thick and 1.0 mm-thick specimens (P&gt;0.05). Redness and yellowness increased with increasing thickness (P&lt;0.001). Regardless of thickness, the FS group had the highest TP00 (16.32±1.54), while the LR group had the lowest TP00 (14.31±1.67). Regardless of material, 0.5 mm-thick specimens demonstrated significantly higher TP00 (17.49±1.10) than 0.7 mm-thick (15.45±0.83) and 1.0 mm-thick (13.11±1.12) specimens. There was no significant difference between the 0.5 mm-thick FS and LD groups (P&gt;0.05) and 1.0 mm-thick LR and LD groups (P&gt;0.05). Conclusions: Even when sharing the same shade, glass ceramics may exhibit varying color and translucency properties due to their distinct chemical compositions and thicknesses.

Risk factors for surgical site infection following cardiac surgery in a region endemic for multidrug resistant organisms

ObjectivesTo identify risk factors for surgical site infections following cardiosurgery in an area endemic for multidrug resistant organisms. DesignSingle-center, historical cohort study including patients who underwent cardiosurgery during a 6-year period (2014–2020). SettingJoint Commission International accredited, multiorgan transplant center in Palermo, Italy. Main outcome measuresSurgical site infection was the main outcome. ResultsOn a total of 3609 cardiosurgery patients, 184 developed surgical site infection (5.1 %). Intestinal colonization with multidrug resistant organisms was more frequent in patients with surgical site infections (69.6 % vs. 33.3 %; p < 0.001). About half of surgical site infections were caused by Gram-negative bacteria (n = 97; 52.7 %). Fifty surgical site infections were caused by multidrug resistant organisms (27.1 %), with extended-spectrum Beta-lactamase-producing Enterobacterales (n = 16; 8.7 %) and carbapenem-resistant Enterobacterales (n = 26; 14.1 %) being the predominant resistance problem. However, in only 24 of surgical site infections caused by multidrug resistant organisms (48 %), mostly carbapenem-resistant Enterobacterales (n = 22), a pathogen match between the rectal surveillance culture and surgical site infections clinical culture was demonstrated. Nevertheless, multivariate logistic regression analysis identified a rectal swab culture positive for multidrug resistant organisms as an independent risk factor for SSI (odds ratio 3.95, 95 % confidence interval 2.79–5.60). Other independent risk factors were female sex, chronic dialysis, diabetes mellitus, previous cardiosurgery, previous myocardial infarction, being overweight/obese, and longer intubation time. ConclusionIn an area endemic for carbapenem-resistant Enterobacterales, intestinal colonization with multidrug resistant organisms was recognized as independent risk factor for surgical site infections. Implications for clinical practiceNo causal relationship between colonization with resistant pathogens and subsequent infection could be demonstrated. However, from a broader epidemiological perspective, having a positive multidrug resistant organisms colonization status appeared a risk factor for surgical site infections. Therefore, strict infection control measures to prevent cross-transmission remain pivotal (e.g., nasal decolonization, hand hygiene, and skin antisepsis).

Low-Temperature and Catalyst-Free Plasma Synthesis of Plastics-Derived Graphene Quantum Dots

The advanced industrial, social, and technological developments in modern society have rendered the production of around 300 million tons of plastic annually, yet only 50% or even less are being recycled. Moreover, the current recycling process is limited to the conversion of plastic wastes (PWs) into hydrocarbon fuels, which also requires the use of high temperatures and energies, long reaction time, and high-cost platinum-based catalysts. Therefore, there is an urgent need to develop a more sustainable and environmentally friendly method to recycle these PWs and possibly into functional materials for diverse applications.We introduce non-equilibrium and low-temperature microplasma technologies to convert PWs into graphene quantum dots (GQDs) at ambient conditions without any additional toxic chemicals, expensive catalysts, and sophisticated vacuum technologies. The reactive species generated by the plasma enables not only rapid deconstruction of PWs into small hydrocarbons moieties, but also simultaneous reconstruction of nanographene domain and nucleation into GQDs. GQDs are zero-dimensional carbon nanomaterials with unique quantum confinement and edge effects, which are hybridized by sp2 carbon in a honeycomb network. The quantum confinement and edge effects bestow GQDs with unique, tunable, and stable photoluminescence (PL) properties. Coupled with the biocompatibility, low toxicity, large surface area, and chemical inertness, GQDs can be employed in various applications, including imaging, sensing, optoelectronics, drug delivery, catalysis, and energy related applications. Nevertheless, the current syntheses of GQDs still need the use of high temperatures, strong acids or reducing agents, long reaction time, and tedious synthesis procedures.Here the utilization of microplasma enables the degradation and conversion of various plastics into functional GQDs with well-controlled structures in one-step at ambient conditions and catalyst-free manner, alleviating the current drawbacks in the GQDs synthesis. Among various PWs, polyethylene terephthalate-derived GQDs (PET-GQDs) exhibit enticing and bright white emission under 365 nm UV irradiation with a Commission Internationale de l’Eclairage 1931 of (0.29, 0.35). Moreover, the colloidal PET-GQDs can be exploited for heavy metal ions detection with a low limit of detection of 8.4 nM, while the composite film state is usable as sensitive temperature tag from 10 – 80 °C and LED panel. Our work provides an insight into the novel technologies for PWs recycling into functional nanomaterials in cost-effective, scalable, and environmentally friendly way.

Structure‐Based Machine Learning Enables Discovery of Mn4+‐Activated Red‐Light Fluorides for Ultrawide‐Gamut Mini‐Light‐Emitting Diodes

AbstractMn4+‐activated fluorides with a saturated red color and sharp line emission are ideal for applications in the light‐emitting diodes (LEDs) backlight for displays. However, the emissions attributed to 2E→4A2 parity and spin‐forbidden transitions limit the design and adjustments of emission wavelength and chromaticity coordinates. Herein, machine learning algorithms are used to build a wavelength‐prediction model for Mn4+‐activated fluorides. The model precisely identifies the key structural features that affect wavelengths and discovers target materials. The predicted candidate Cs2NaAlF6:Mn4+ (CNAF) with a long‐wavelength zero‐phonon‐line emission at 628 nm exhibits a redshift in comparison with other reported Mn4+‐activated fluorides and commercial K2SiF6:Mn4+, but maintains narrow spectral emission with full‐width half maximum (FWHM) of 11.2 nm. The redshift and narrow spectra result in a color purity of 99.7% and Commission Internationale de L'Eclairage (CIE) chromaticity coordinate of (0.7032,0.2967) that is close to the pure red‐light point of Recommendation BT. 2020 (Rec. 2020). Moreover, CNAF is prepared as a transparent red‐light film, and the device fabricated using the blue‐light mini‐LEDs, green quantum‐dot film, and CNAF film exhibits a wide color‐gamut of 121.5% National Television Standards Committee (NTSC) or 90.6% Rec. 2020, suggesting that CNAF has potential for wide‐color‐gamut displays.

Synthesis and characterization of thermally stable red light-emitting Eu3+ activated Li7La3Zr2O12 phosphors for solid-state lighting applications

To enhance the photoluminescence property of Li7La3Zr2O12 (LLZO), Eu was doped using a solid-state synthesis technique. X-ray diffraction and Raman spectroscopy analysis were used to examine the crystal structure of the synthesized phosphors. The optical band gap values of pristine and Eu3+ doped LLZO phosphor investigated using ultraviolet-visible (UV-Vis) spectroscopy were measured to be 2.74 and 2.97 eV, respectively. The wavelengths of pure and doped LLZO samples were measured and fitted by the Commission Internationale de l’Eclairage (CIE) chromatic coordinate graph. These samples were found to emit blue emission at 354 nm (pure LLZO) and red emission at 464 nm (doped phosphor), which correspond to the 5D0 to 7Fj (j = 0, 1, 2, and 3) transition. The purity of the color and correlated color temperature with respect to the 0.9 M.W% Eu3+ doped (activated) LLZO sample were estimated to be 80% and 1719K, respectively. The indication of its maximum emissive capability at this rate was found suitable for aesthetic lighting applications.

Synthesis, structure and optoelectronic properties of iridium(III) complexes bearing a four-membered Ir-N-C[sbnd]N chelate structure

Herein four novel iridium(III) complexes (tfpmd)2Ir(dpppy) (Ir1a, tfpmd = 2-(4-(trifluoromethyl) phenyl) pyrimidine, dpppy = P,P-diphenyl-N-(pyridin-2-yl)phosphinic amide), (tfpmd)2Ir(dppq) (Ir1b, dppq = P,P-diphenyl-N-(quinolin-2-yl)phosphinic amide), (tfpqz)2Ir(dpppy) (Ir2a, tfpzq = 4-(4-(trifluoromethyl) phenyl) quinazoline) and (tfpqz)2Ir(dppq) (Ir2b) were synthetized, and their structures, opto-physical, and electro-chemical properties were investigated in detail. The crystal structure shows that these complexes exhibit pseudo-octahedral geometry around iridium atom coordinated by C, N atoms from cyclometalated and ancillary ligands. Interestingly, two coordinated nitrogen atoms from the ancillary ligand form an unusual quaternary ring with the central iridium ion. Ir1a and Ir1b emit pure-green light with Commission Internationale de L'Eclairage (CIE) color coordinates of (0.25, 0.67) and (0.22, 0.67), respectively, in CH2Cl2 solution. With the increase of the degree of conjugation of the cyclometalated ligand from tfpmd to tfpqz, the luminescence of complexes Ir2a and Ir2b is greatly red-shifted, and pure-red emission with CIE coordinates of (0.66, 0.34) and (0.66, 0.34), respectively, is obtained. The photophysical behaviors were reasonably explained by quantum chemical calculations. The calculation results shows that their emission is ascribed to the mixed 3MLCT (metal-ligand charge transfer, dπ(Ir)→π*(cyclometalated ligand)) and 3LLCT (ligand-ligand charge transfer, π(ancillary ligand)→π*(cyclometalated ligand)) states. Owing to their good thermal and electrochemical stabilities, organic light emitting diode (OLED) devices with dual-emitting layer structure and a space interlayer were fabricated and exhibited high electroluminescent properties and mild efficiency roll-off (14%-21%).

Evolución de la percepción de la cultura de seguridad de los profesionales sanitarios en una urgencia pediátrica

Background and aimSafety culture (SC) is a fundamental tool for minimizing adverse events and improving safety and quality of care. Our objective, therefore was to analyze the evolution of the SC of healthcare professionals in a pediatric emergency department (PED) after the implementation of a risk management system for patient safety based on the UNE:EN:ISO 179003 Standard and the execution of new safe practices for Joint Commission International accreditation. At the same time describe the current strengths and weaknesses. MethodsQuasi-experimental, single-center study. All PED professionals participated in the study. An initial measurement of SC was performed through the Hospital Survey on Patient Safety Culture (HSOPS) questionnaire of the Agency for Healthcare Research and Quality adapted to Spanish in 2014. Pro-patient safety strategies were implemented between 2015 and 2022. A subsequent measurement was performed in 2022. ResultsThe response rate in 2014 was 55% and 78% in 2022. On both occasions the group with the highest participation was nurses with 35.1% and 34.8%, respectively.Five dimensions improved after the interventions: frequency of adverse events (25.2%, p<0.001), organizational learning (25%, p<0.001), feedback and communication about errors (22.3%, p<0.001), non-punitive response to errors (6.5%, p = 0.176), and management support (4%, p = 0.333). ConclusionsThe actions carried out had a positive influence on organizational learning and the frequency of adverse events reported and communication within the team. In contrast, the perception of SC did not increase.

Carbonyl- and Nitrogen-Embedded Multi-Resonance Emitter with Ultra-Pure Green Emission and High Electroluminescence Efficiencies.

Multi-resonance thermally activated delayed fluorescence (MR-TADF) emitters with narrow emission spectra have garnered significant attention in future organic light-emitting diode (OLED) displays. However, current C=O/N-embedded MR-TADF systems still lack satisfactory performance in terms of electroluminescence bandwidths and external quantum efficiencies (EQEs). In this study, a C=O/N-embedded green MR-TADF emitter, featuring two acridone units incorporated in a sterically protected 11-ring fused core skeleton, is successfully synthesized through finely controlling the reaction selectivity. The superior combination of multiple intramolecular fusion and steric wrapping strategies in the design of the emitter not only imparts an extremely narrow emission spectrum and a high fluorescence quantum yield to the emitter but also mitigates aggregation-induced spectral broadening and fluorescence quenching. Therefore, the emitter exhibits leading green OLED performance among C=O/N-based MR-TADF systems, achieving an EQE of up to 37.2 %, a full width at half maximum of merely 0.11 eV (24 nm), and a Commission Internationale de l'Éclairage coordinate of (0.20, 0.73). This study marks a significant advance in the realization of ideal C=O/N-based MR-TADF emitters and holds profound implications for the design and synthesis of other MR-TADF systems.