Suppression of Thermal Quenching for CsPbX₃ (X = Cl, Br, and I) Quantum Dots via the Hollow Structure of SrTiO₃ and Light-Emitting Diode Applications

All-inorganic perovskite quantum dots (PQDs, CsPbX3, X = Cl, Br, and I) show outstanding application prospects in the field of photoelectric devices. In recent years, the development of PQDs has greatly improved their stability to water, oxygen, and light. However, thermal quenching of PQDs greatly limits their practical application. Herein, we embed PQDs into ATiO3 (A = Ca, Ba, and Sr) of three different mesoporous spherical structures to explore the effect on thermal quenching of PQDs. Because of the unique mesoporous hollow microsphere structure and low thermal conductivity of SrTiO3, it can effectively block the heat transfer and improve the thermal quenching of PQDs. The photoluminescence (PL) intensity of CsPbBr3@SrTiO3 composites is 72.6% of the initial intensity after heating to 120 °C. Moreover, the PL intensity of CsPbBr3@SrTiO3 composites remains about 80% of the initial value even when stored in air for 20 days or irradiated by 365 nm UV light for 48 h. A neutral white light-emitting diode is assembled by a blue chip, CsPbBr3@SrTiO3 composites, and red phosphor of K2SiF6:Mn4+, which has a color temperature of 5389 K and a color gamut covered 133% of National Television Standards Committee (NTSC)

Ultrafast Self-Crystallization of High-External-Quantum-Efficient Fluoride Phosphors for Warm White Light-Emitting Diodes

In this study, we used HF (as good solvent) to dissolve K₂GeF₆ and K₂MnF₆ and added ethanol (as poor solvent) to cause ultrafast self-crystallization of K₂GeF₆:Mn⁴⁺ crystals, which had an unprecedentedly high external quantum efficiency that reached 73%. By using the red phosphor, we achieved a high-quality warm white light-emitting diode with color-rendering index of <i>R</i>_a = 94, <i>R</i>9 = 95, luminous efficacy of 150 lm W^–1, and correlated color temperature at 3652 K. Furthermore, the good–poor solvent strategy can be used to fast synthesize other fluorides

Ultrafast Self-Crystallization of High-External-Quantum-Efficient Fluoride Phosphors for Warm White Light-Emitting Diodes

In this study, we used HF (as good solvent) to dissolve K₂GeF₆ and K₂MnF₆ and added ethanol (as poor solvent) to cause ultrafast self-crystallization of K₂GeF₆:Mn⁴⁺ crystals, which had an unprecedentedly high external quantum efficiency that reached 73%. By using the red phosphor, we achieved a high-quality warm white light-emitting diode with color-rendering index of <i>R</i>_a = 94, <i>R</i>9 = 95, luminous efficacy of 150 lm W^–1, and correlated color temperature at 3652 K. Furthermore, the good–poor solvent strategy can be used to fast synthesize other fluorides

Comparison of Oral Paracetamol versus Ibuprofen in Premature Infants with Patent Ductus Arteriosus: A Randomized Controlled Trial

<div><p>Trial Design</p><p>Oral ibuprofen has demonstrated good effects on symptomatic patent ductus arteriosus (PDA) but with many contraindications and potential side-effects. In the past two years, oral paracetamol administration to several preterm infants with PDA has been reported. Here, a randomized, non-blinded, parallel-controlled and non-inferiority trial was designed to evaluate the efficacy and safety profiles of oral paracetamol to those of standard ibuprofen for PDA closure in premature infants.</p><p>Methods</p><p>One hundred and sixty infants (gestational age ≤34 weeks) with echocardiographically confirmed PDA were randomly assigned to receive either oral paracetamol (n = 80) or ibuprofen (n = 80). After the initial treatment course in both groups, the need for a second course was determined by echocardiographic evaluation. The main outcome was rate of ductal closure, and secondary outcomes were adverse effects and complications.</p><p>Result</p><p>The ductus was closed in 65 (81.2%) infants of the paracetamol group compared with 63 (78.8%) of the ibuprofen group. The 95% confidence interval of the difference between these groups was [−0.080,0.128], demonstrating that the effectiveness of paracetamol treatment was not inferior to that of ibuprofen. In fact, the incidence of hyperbilirubinemia or gastrointestinal bleeding in the paracetamol group was significantly lower than that of the ibuprofen group. No significant differences in other clinical side effects or complications were noted.</p><p>Conclusion</p><p>This comparison of drug efficacy and safety profiles in premature infants with PDA revealed that oral paracetamol was comparable to ibuprofen in terms of the rate of ductal closure and even showed a decreased risk of hyperbilirubinemia or gastrointestinal bleeding. Therefore, paracetamol may be accepted as a first-line drug treatment for PDA in preterm infants.</p><p>Trial Registration</p><p>ChiCTR.org ChiCTR-TRC-12002177</p></div

Baseline characteristics of study patients.

<p>pregnancy induced hypertension syndrome(PIH).</p

Safety profiles of paracetamol and ibuprofen treatments.

<p>Safety profiles of paracetamol and ibuprofen treatments.</p

Advancing Red-Emitting Fluoride Phosphors for Highly Stable White Light-Emitting Diodes: Crystal Reconstruction and Covalence Enhancement Strategy

Mn4+-activated fluoride red phosphors exhibit excellent luminescence properties. However, a persistent technical challenge lies in their poor moisture resistance. Current strategies primarily focus on surface modifications to effectively shield the [MnF6]2– species from water molecules while neglecting the underlying structure of the fluoride matrix. In this study, we introduce Si4+ and Ge4+ ions into the K2TiF6:Mn4+ crystal to create covalent fluoride solid solutions, namely, K2Ti1–xSixF6:Mn4+ and K2Ti1–yGeyF6:Mn4+, through crystal reconstruction. The findings reveal that the incorporation of Si4+ leads to increased particle size, enhanced luminescence intensity (by 40%), and improved moisture resistance. Furthermore, after undergoing 1000 h of aging at high temperature and high humidity conditions, the white LED featuring the K2Ti0.97Si0.03F6:Mn4+ phosphor demonstrates remarkable durability by retaining 90% of its initial luminous efficacy. This performance surpasses that of the device utilizing the K2TiF6:Mn4+ phosphor, which only retains 74% of its original efficacy. The crystal reconstruction method and covalent enhancement strategy proposed in this work contribute to enhancing the luminescence efficiency and moisture resistance of fluoride phosphors, thereby offering new insights for advancing the development of high-efficiency and highly stable white light LED devices

Development of Evaporative Light Scattering Detector for Capillary Electrochromatography and Capillary Liquid Chromatography

The paper describes a microfluidic evaporative light scattering detector (μELSD) for capillary electrochromatography and capillary liquid chromatography. The detector, consisting of a microfluidic nebulizer, a miniaturized evaporative module, a sheath gas module, and a light scattering chamber, was developed and optimized. Carrier gas exits from an extremely narrow circular gap (about 5 μm) between the spraying capillary o.d. and the nozzle i.d., impacting on the mobile phase liquid with supersonic velocity, to nebulize the effluent of a few hundred nL/min from the capillary outlet. The evaporation process was found to be accomplished at ambient temperature. A sheath gas module featuring a structural necking subsequent to drift tube endings was found to enhance the reproducibility and increase the S/N. Excellent linearity of the optimal μELSD was 3 orders of magnitude (0.2–40 ng; <i>R</i>² = 0.9998). The limit of detection (LOD) for glucose with a capillary column was 100 pg. Finally, the μELSD coupled to pressurized capillary eletrochromatography (pCEC) was applied to the analysis of six active components in traditional Chinese medicine extract, demonstrating the feasibility of the detector for capillary liquid separation system

Redistribution of Activator Tuning of Photoluminescence by Isovalent and Aliovalent Cation Substitutions in Whitlockite Phosphors

Many strategies, including double substitution, addition of charge compensation, cation-size-mismatch and neighboring-cation substitution, have contributed to tuning photoluminescence of phosphors for white light-emitting diodes. These strategies generally involve modification of a certain special site where the activator occupies; tuning strategy based on multiple cation sites is very rare and desirable. Here we report that isovalent (Sr²⁺) and aliovalent (Gd³⁺) substitutions for Ca²⁺ tune the photoluminescence from one band to multiple bands in whitlockite β-Ca_3–<i>x</i>Sr_<i>x</i>(PO₄)₂:Eu²⁺ and β-Ca_{3–3<i>y</i>/7}Gd_2<i>y</i>/7(PO₄)₂:Eu²⁺ phosphors. The saltatory variation of the emission spectra is caused by the removal of Eu²⁺ from the site M(4) to other sites. Moreover, we found the mechanisms of dopant redistribution tuning the luminescence are different. The incorporation of Gd³⁺ makes the site M(4) empty according to the scheme 3Ca²⁺ = 2Gd³⁺ + □, while Sr²⁺ substitution causes the cation sites to be enlarged due to cation size mismatch. Additionally, the influence of the cation substitutions on the photoluminescence thermal stability of phosphors is researched. The strategies, emptying and enlarging sites, developed herein are expected to provide a general route for tuning luminescence of phosphors with multiple sites in the future

Changing Ce³⁺ Content and Codoping Mn²⁺ Induced Tunable Emission and Energy Transfer in Ca_2.5Sr_0.5Al₂O₆:Ce³⁺,Mn²⁺

A series of color-tunable Ce³⁺ single-doped and Ce³⁺, Mn²⁺ codoped Ca_2.5Sr_0.5Al₂O₆ phosphors were synthesized by a high-temperature solid-state reaction. The crystal structure, luminescent properties, and energy transfer were studied. For Ca_2.5Sr_0.5Al₂O₆:Ce³⁺ phosphors obtained with Al­(OH)₃ as the raw material, three emission profiles were observed. The peak of photoluminescence (PL) spectra excited at ∼360 nm shifts from 470 to 420 nm, while that of the PL spectra excited at 305 nm stays unchanged at 470 nm with the increase of Ce³⁺ content. Furthermore, the peak of PL spectra is situated at 500 nm under excitation at ∼400 nm. The relationship between the luminescent properties and crystal structure was studied in detail. Ce³⁺, Mn²⁺ codoped Ca_2.5Sr_0.5Al₂O₆ phosphors also showed interesting luminescent properties when focused on the PL spectra excited at 365 nm. Obvious different decreasing trends of blue and cyan emission components were observed in Ca_2.5Sr_0.5Al₂O₆:0.11Ce³⁺,<i>x</i>Mn²⁺ phosphors with the increase in Mn²⁺ content, suggesting different energy transfer efficiencies from blue- and cyan-emitting Ce³⁺ to Mn²⁺. Phosphors with high color-rendering index (CRI) values are realized by adjusting the doping content of both Ce³⁺ and Mn²⁺. Studies suggest that the Ca_2.5Sr_0.5Al₂O₆:Ce³⁺,Mn²⁺ phosphor is a promising candidate for near UV-excited w-LEDs