Didodecyldimethylammonium Bromide Research Articles

Charge Inversion by Monovalent Hydroxide Ions.

The interaction between the hydroxide ion (OH-) and the headgroup of a model cationic lipid (DPTAP, 1,2-dipalmitoyl-3-trimethylammonium-propane chloride) was investigated for different concentrations of NaOH solutions by using sum-frequency vibrational spectroscopy. The OH signal (3000-3700 cm-1) of the interfacial water under the Langmuir monolayer of DPTAP decreased with increasing NaOH concentration, due to screening of the surface charge by OH- counterions. Surprisingly, after reaching a minimum at 5 mM NaOH, the OH signal steadily increased. The phase-sensitive spectra revealed a sign change in the OH stretch band, indicating the overcompensation of the surface charge by OH-. By contrast, for a DODAB (didodecyldimethylammonium bromide) monolayer (a cationic surfactant without ester groups), the OH stretch signal decreased monotonically with NaOH addition. This charge inversion behavior is driven by the specific interaction between the ester moiety of DPTAP and the OH- that overcomes the Coulomb repulsion between the adsorbed ions.

The study of micellar transitions in mixed systems of dibranched cationic/nonionic fluorinated surfactants using various physicochemical methods

AbstractIn this study, a new method was introduced to induce micellar transitions by using vesicles formed from mixed surfactants, which offer enhanced stability. Different physicochemical analysis methods were used to study the transition mechanism and the aggregation behavior of the mixed aqueous system composed of the double‐chain cationic didodecyldimethylammonium bromide (DDAB) and a single‐chain nonionic fluorinated surfactant undecafluoro n‐pentyl decaoxyethylene ether (C5F11(EO)10), by varying the fraction of DDAB, then the total surfactant concentration of DDAB/C5F11(EO)10 mixed system at XDDAB = 0.9. The obtained results indicated that the addition of the fluorinated surfactant C5F11(EO)10 to the mixed system resulted in a reduction of the surface tension (γ) and a decrease in the Electrical conductivity (K). Furthermore, even at high total concentrations of the mixed system, the conductivity and charge density at the surface remained stable. As XDDAB values increased, a higher degree of dissociation (α) was observed, along with negative values in the thermodynamic parameters of micellization (Δ, Δ, and Δ), confirming the transition from micelles to vesicles. The dynamic light scattering (DLS) analysis revealed the formation of two stable types of aggregates at both low and high concentrations, as supported by the zeta potential (ζ). Upon increasing the concentration of surfactants, UV–Vis absorption measurements indicated that small spherical micelles grow into large multilamellar vesicles, as evidenced by an increase in turbidity and confirmed transmission electron microscopy images.

Effect of Mn2+ doping and DDAB-assisted postpassivation on the structural and optical properties of CsPb(Cl/Br)3 halide perovskite nanocrystals

Cesium lead halide perovskite (CsPbX3; X = Cl, Br, I) nanocrystals showing intense band-edge emission and high photoluminescence quantum yield are known to be a potential candidate for application in optoelectronic devices. However, controlling toxicity due to the presence of Pb2+ in lead-based halide perovskites is a major challenge for the environment that needs to be tackled cautiously. In this work, we have partially replaced Pb2+ with Mn2+ ions in the CsPb(Cl/Br)3 nanocrystals and investigated their impact on the structural and optical properties. The Rietveld refinement shows that CsPbCl2Br nanocrystals possess a cubic crystal structure with Pm 3̅ m space group, the Mn2+ doping results in the contraction of the unit cell. The CsPb(Cl/Br)3: Mn nanocrystals show a substantial change in the optical properties with an additional emission band at ∼588 nm through a d-d transition, changing the emission color from blue to pink. Here, a didodecyldimethylammonium bromide (DDAB) ligand that triggers both anion and ligand exchange in the CsPb(Cl/Br)3: Mn nanocrystals have been used to regulate the exchange reaction and tune the emission color of halide perovskites by changing the peak position and the PL intensities of band-edge and Mn2+ defect states. We have also shown that oleic acid helps in the desorption of oleylamine capping from the CsPb(Cl/Br)3: Mn nanocrystal surfaces and DDAB, resulting in the substitution of Cl− with Br− as well as provides capping with shorter branched length ligand which led to increase in the overall PL intensity by many folds.

Fungicide-Loaded Liposomes for the Treatment of Fungal Diseases in Agriculture: An Assessment of Botrytis cinerea.

In this work, liposomes loaded with the fungicide, Fludioxonil (FLUD), for the containment of fungal diseases in agriculture were developed. Three types of vesicles with different compositions were compared: (I) plain vesicles, composed of soy phosphatidylcholine and cholesterol; (II) PEG-coated vesicles, with an additional polyethylene glycol coating; and (III) cationic vesicles, containing didodecyldimethylammonium bromide. Nanometric-sized vesicles were obtained both by the micelle-to-vesicle transition method and by the extrusion technique, and encapsulation efficiency, drug loading content, and Zeta potential were determined for all the samples. The extruded and PEGylated liposomes were the most stable over time and together with the cationic ones showed a significant prolonged FLUD release capacity. The liposomes' biological activity was evaluated on conidial germination, germ tube elongation and colony radial growth of the ascomycete Botrytis cinerea, a phytopathogenic fungus affecting worldwide many important agricultural crops in the field as well as in the postharvest phase. The extruded and PEGylated liposomes showed greater effectiveness in inhibiting germ tube elongation and colony radial growth of the fungal pathogen, even at 0.01 µg·mL-1, the lowest concentration assessed.

Size Dependence of Ultrafast Electron Transfer from Didodecyl Dimethylammonium Bromide-Modified CsPbBr3 Nanocrystals to Electron Acceptors.

Charge transfer efficiencies in all-inorganic lead halide perovskite nanocrystals (NCs) are crucial for applications in photovoltaics and photocatalysis. Herein, CsPbBr3 NCs with different sizes are synthesized by varying the ligand contents of didodecyl dimethylammonium bromide at room temperature. Adding benzoquinone (BQ) molecules leads to a decrease in the PL intensities and PL decay times in NCs. The electron transfer (ET) efficiency (ηET) increases with NC size in complexes of CsPbBr3 NCs and BQ molecules (NC-BQ complexes), when the same concentration of BQ is maintained, as investigated by transient photobleaching and photoluminescence spectroscopies. Controlling the same number of attached BQ acceptor molecules per NC induces the same ηET in NC-BQ complexes even though with different NC sizes. Our findings provide new insights into ultrafast charge transfer behaviors in perovskite NCs, which is important for designing efficient light energy conversion devices.

Nanocomposite alginate hydrogel loaded with propranolol hydrochloride kolliphor® based cerosomes as a repurposed platform for Methicillin-Resistant Staphylococcus aureus-(MRSA)-induced skin infection; in-vitro, ex-vivo, in-silico, and in-vivo evaluation.

Nanocomposite alginate hydrogel containing Propranolol hydrochloride (PNL) cerosomes (CERs) was prepared as a repurposed remedy for topical skin Methicillin-Resistant Staphylococcus aureus (MRSA) infection. CERs were formed via an ethanol injection technique using different ceramides, Kolliphores® as a surfactant, and Didodecyldimethylammonium bromide (DDAB) as a positive charge inducer. CERs were optimized utilizing 13. 22 mixed-factorial design employing Design-Expert® software, the assessed responses were entrapment efficiency (EE%), particle size (PS), and zeta potential (ZP). The optimum CER, composed of 5mg DDAB, ceramide VI, and Kolliphor® RH40 showed tubular vesicles with EE% of 92.91 ± 0.98%, PS of 388.75 ± 18.99nm, PDI of 0.363 ± 0.01, and ZP of 30.36 ± 0.69 mV. Also, it remained stable for 90 days and manifested great mucoadhesive aspects. The optimum CER was incorporated into calcium alginate to prepare nanocomposite hydrogel. The ex-vivo evaluation illustrated that PNL was permeated in a more prolonged pattern from PNL-loaded CERs nanocomposite related to PNL-composite, optimum CER, and PNL solution. Confocal laser scanning microscopy revealed a perfect accumulation of fluorescein-labeled CERs in the skin. The in-silico investigation illustrated that the PNL was stable when mixed with other ingredients in the CERs and confirmed that PNL is a promising candidate for curing MRSA. Moreover, the PNL-loaded CERs nanocomposite revealed superiority over the PNL solution in inhibiting biofilm formation and eradication. The PNL-loaded CERs nanocomposite showed superiority over the PNL-composite for treating MRSA infection in the in-vivo mice model. Histopathological studies revealed the safety of the tested formulations. In conclusion, PNL-loaded CERs nanocomposite provided a promising, safe cure for MRSA bacterial skin infection.

Self-Assembly of Lamellae-in-Lamellae by Double-Tail Cationic Surfactants.

The molecular structures of surfactants play a pivotal role in influencing their self-assembly behaviors. In this work, using simulations and experiments, an unconventional hierarchically layered structure in the didodecyldimethylammonium bromide (DDAB)/water binary system: lamellae-in-lamellae is revealed, a new self-assembly structure in surfactant system. This self-assembly structure refers to a lamellar structure with a shorter periodic length (inner lamellae) embedded in a lamellar phase with a longer periodic length (outer lamellae). The normal vectors of these two lamellar regions orient perpendicularly. In addition, it is observed that this lamellar-in-lamellar phase disappears when the two tails of the cationic surfactants become longer. The formation of the lamellar-in-lamellar architecture arises from multiple interacting factors. The key element is that the short tails of the DDAB surfactants enhance hydrophilicity and rigidity, which facilitates the formation of the inner lamellae. Moreover, the lateral monolayer of the inner lamellae provides shielding from the water and prompts the formation of the outer lamellae. These findings indicate that molecular structures and flexibility can profoundly redirect the hierarchical self-assembly behaviors in amphiphilic systems. More broadly, this work presents a new strategy to deliberately program hierarchical nanomaterials by designing specific surfactant molecules to act as tunable scaffolds, reactors, andcarriers.

Effects of surfactants on the adsorption of norfloxacin onto ferrihydrite: comparison between anionic and cationic surfactants

ABSTRACT There is little information on how widespread surfactants affect the adsorption of norfloxacin (NOR) onto iron oxide minerals. In order to elucidate the effects of various surfactants on the adsorption characteristics of NOR onto typical iron oxides, we have explored the different influences of sodium dodecylbenzene sulfonate (SDBS), an anionic surfactant, and didodecyldimethylammonium bromide (DDAB), a cationic surfactant, on the interactions between NOR and ferrihydrite under different solution chemistry conditions. Interestingly, SDBS facilitated NOR adsorption, whereas DDAB inhibited NOR adsorption. The adsorption-enhancement effect of SDBS was ascribed to the enhanced electrostatic attraction, the interactions between the adsorbed SDBS on ferrihydrite surfaces and NOR molecules, and the bridging effect of SDBS between NOR and iron oxide. In comparison, the adsorption-inhibition effect of DDAB owning to the adsorption site competitive adsorption between NOR and DDAB for the effective sites as well as the steric hindrance between NOR-DDAB complexes and the adsorbed DDAB on ferrihydrite surfaces. Additionally, the magnitude of the effects of surfactants on NOR adsorption declined with increasing pH values from 5.0 to 9.0, which was related to the amounts of surfactant binding to ferrihydrite surfaces. Moreover, when the background electrolyte was Ca2+, the enhanced effect of SDBS on NOR adsorption was caused by the formation of NOR-Ca2+-SDBS complexes. The inhibitory effect of DDAB was due to the DDAB coating on ferrihydrite, which undermined the cation-bridging effect. Together, the findings from this work emphasize the essential roles of widely existing surfactants in controlling the environmental fate of quinolone antibiotics.

Removal and detoxification of iprodione in water using didodecyldimethylammonium bromide-montmorillonite organoclay and manganese dioxide.

Combination of organoclay sorption with manganese(IV) oxide (MnO2) catalyzed catechol oxidation was studied for the removal of a dicarboximide fungicide, iprodione, from water. Iprodion in water was sorbed on didodecyldimethylammonium bromide (DDAB)-modified montmorillonite (MT) organoclay and converted into the degraded product, 3,5-dichloroaniline (DCA). The degree of sorption increased by the modification with DDAB, because of the formation of a hydrophobic region for the incorporation of iprodione and negligibly interfered by coexisting MnO2. The half-life for the degradation of irodione in water at 25°C was 7 days, whreas it reduced to 15min in the organoclay. The activation energy, 65.4 ± 4.8kJmol-1, for the first-order reaction in the aqueous solution (pH 7.0) decreased to 43.9 ± 1.8kJmol-1 in the organoclay, indicating the catalytic activity of the organoclay that accelerates the hydrolysis reaction of iprodione. In the coexistence of appropriate amounts of MnO2 and catechol, the degraded product, DCA, reacted with oxidized products of catechol to form a water-insoluble precipitate and was successfully eliminated from water. The results obtained in the present study strongly suggest the applicability of the combined method of organoclay sorption method and MnO2-catalyzed oxidation for the diffusion control of toxic agrochemicals.

MODIFICATION OF PINDIGA BENTONITE CLAY WITH DIDODECYLDIMETHYLAMMONIUM BROMIDES SURFACTANT FOR FOUNDRY USE

Bentonite clay from Pindiga, Gombe State, Nigeria, was surface modified with didodecyldimethylammonium bromides (DDAB) by the Base Exchange (cation exchange capacity) method for its possible use in foundries. The surfaces of the unmodified and modified Pindiga bentonite clay were characterised by means of spectroscopic, diffraction, and scanning methods (X-Ray fluorescence spectrometry (XRF)Fourier-transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM).XRF showed that unmodified sample was rich of montmorillonite (MMt) with ca +2 as exchangeable cation, FTIR analysis revealed that unmodified water absorption causes stretching and bending vibrations for hydroxyl groups, with the most intense bands in the low-frequency region, while DDAB organo-bentonites showed slight changes in wave bands, with a strong methyl band and a weak methyl band indicative of long-chain linear aliphatic structure. The basal spacing of the unmodified bentonite sample was 1.52 nm, and after modification with DDAB, it improved to 2.1 nm as determined from the X-ray diffraction (XRD) analysis. Results of the SEM images revealed rougher surfaces with uniformly dispersed small particles of grain-like structures characteristic of the unmodified, while theorgano-modified bentoniterevealed clusters of different sizes and shapes, larger Fe 3+ ions replacing smaller Al 3+ ions at octahedral sites, discontinuous layers enveloping large grains, polygonal growth foams with octahedral and tetrahedral shapes, mixed layers of calcium bentonite, and particle sizes less than 200nm. The study concluded that modified bentonite with didodecyldimethylammonium bromides gives good microstructure, increases rigidity, and improve thermal stability, to the organoclays. Therefore, it is recommended that DDAB bentonite be used as binder for foundries.

Modulation of Photoinduced Phase Segregation and Stress-Driven Nanoscale Cracking in Hybrid Halide Perovskite Solar Cells.

The negative effect of photoinduced halide segregation (PIHS) on the properties of hybrid halide perovskites poses a major obstacle for its future commercial application. Therefore, the in-depth understanding of halide-ion segregation and its causes is an urgent and intractable problem. When PIHS reaches a certain threshold, it will aggravate the deterioration of the film surface morphology and form nanoscale cracks. Herein, the formation mechanism and types of cracks are revealed by exploring the stress distribution in the film. Using the femtosecond time-resolved transient absorption spectroscopy, the ultrafast formation of the iodine rich phase is observed, which appears earlier than the bromine rich phase. In addition, the introduction of organic ligand didodecyldimethylammonium bromide can significantly inhibit PIHS and improve the surface morphology of the film, which can promote the device efficiency from 9.63 to 11.20%. This work provides a novel perspective for the exploration of the PIHS.

Influence of cellulose nanofibers on the behavior of Pickering emulsions. Part II: Thixotropy and dynamic-mechanical tests

Nonlinear rheology of Pickering emulsions is used to further investigate the nonlinear and unrecoverable transformation of inner structures, which is beyond the linear viscoelastic regime of tiny structural disturbances. Exploring various rheological methods plays a vital role in emulsion applications, such as simulating the macroscopic structural transformation between static and liquidlike flow states, strain overshoot, and regeneration for broken structures. According to our previous studies, cellulose nanofibers (CNFs) Pickering emulsions are a typical system for investigating polymer-based emulsions with the auxiliary surfactant [didodecyldimethylammonium bromide (DDAB)] for enhancing CNF absorption. To further study different rheological properties by varying CNF or DDAB contents, multiple interval thixotropic test, large amplitude oscillatory shear, and concentration-time-dependent superposition are employed to study the linear viscoelasticity and structural transformation of nonlinear range. This research was conducted based on the previous published works [Cui et al., Materials 15, 8285 (2022)] as a further characterization for the same sample series.

Universal Surface Repairing Strategy Enabling Suppressed Auger Recombination in CsPbBr3 Perovskite Quantum Dots for Low Threshold Lasing in a Superlattice Microcavity

AbstractLead halide perovskite quantum dots (LHP QDs) emerge as versatile photonic sources in electroluminescence and laser devices. Their applications in optoelectronic devices are hindered by surface distortion and ligand stripping during the purification process. In addition, the device performance roll‐off suffers from the ultrafast non‐radiative Auger recombination (AR). To address these issues, herein, CsPbBr3 QDs are prepared with sizes ranging from 6.5 to 9.2 nm and the universal surface repairing strategy is proved to efficiently increase the biexciton lifetime and quantum yield up to 1.4 and 3 times, respectively. The strategy provides a PbBrx rich surface and strong binding didodecyldimethylammonium bromide (DDAB) ligands to achieve near‐unity photoluminescence efficiency, which significantly improves their stability against anti‐solvents and aging in ambient conditions. A single‐mode laser device is realized by self‐assembling the QDs into superlattice as optical microcavity, with low threshold of 9.45 µJ cm−2, quality factor of 2187 and ultrafast lifetime of 3.22 ps. The superlattice laser is demonstrated as an optical encoder with large coding bandwidth of 0.133 THz. This work proposes new insight into the non‐radiative AR process in these single‐component CsPbBr3 QDs, and will pave the way for optoelectronic devices working in intense conditions.

The Reversible Transformation of a Vesicular Aggregate in Response to a pH Oscillation

The transformation of amphiphilic molecular assemblies in response to chemical oscillations is fundamental in biological systems. The reversible transformation of a vesicular aggregate (VA) in response to a pH oscillation is presented in this study. A VA composed of the cationic surfactant didodecyldimethylammonium bromide is transformed using a pH oscillation ranging between 3 and 7. When the VA attains a stable structure at extreme pH values, the transformation reaches the irreversible stage. However, the addition of a phosphate buffer to the VA suspension changes the pH oscillation pattern from being rectangular to triangular and decreases the oscillation amplitude, successfully achieving the reversible transformation of the VA. Maintaining the non-equilibrium (transient) structures throughout the transformation and not falling into the equilibrium state with a varying pH are essential for the reversible transformation. This may be common and essential for dynamics in biological cells.

Effects of excipients on the interactions of self-emulsifying drug delivery systems with human blood plasma and plasma membranes.

Due to its versatility in formulation and manufacturing, self-emulsifying drug delivery systems (SEDDS) can be used to design parenteral formulations. Therefore, it is necessary to understand the effects of excipients on the behavior of SEDDS formulations upon parenteral administration, particularly their interactions with blood plasma and cell membranes. In this study, we prepared three neutrally charged SEDDS formulations composed of medium-chain triglycerides as the oil phase, polyoxyl-35 castor oil (EL35) and polyethylene glycol (15)-hydroxystearate (HS15) as the nonionic surfactants, medium-chain mono- and diglycerides as the co-surfactant, and propylene glycol as the co-solvent. The cationic surfactant, didodecyldimethylammonium bromide (DDA), and the anionic surfactant, sodium deoxycholate (DEO), were added to the neutral SEDDS preconcentrates to obtain cationic and anionic SEDDS, respectively. SEDDS were incubated with human blood plasma and recovered by size exclusion chromatography. Data showed that SEDDS emulsion droplets can bind plasma protein to different extents depending on their surface charge and surfactant used. At pH 7.4, the least protein binding was observed with anionic SEDDS. Positive charges increased protein binding. SEDDS stabilized by HS15 can adsorb more plasma protein and induce more plasma membrane disruption activity than SEDDS stabilized by EL35. These effects were more pronounced with the HS15 + DDA combination. The addition of DDA and DEO to SEDDS increased plasma membrane disruption (PMD) activities, and DDA (1% w/w) was more active than DEO (2% w/w). PMD activities of SEDDS were concentration-dependent and vanished at appropriate dilution ratios.

Kinetic and adsorption isotherm studies of Malachite Green dye onto surfactant-tailored alginate hydrogel beads: An influence of surfactant hydrophobicity

This study details the synthesis and characterization of surfactant-modified sodium alginate hydrogel beads crosslinked with Ba2+ ions through ionotropic gelation. Cationic surfactants such as, dodecyltrimethylammonium bromide (DTAB), didodecyldimethylammonium bromide (DDAB), and butanediyl-α,ω-bis-(dimethyldodecylammonium bromide) (GEM), were employed in the modification process. The surfactant-modified ALG-DTAB, ALG-DDAB, and ALG-GEM beads were investigated for the removal of cationic dye Malachite Green (MG) to elucidate the impact of hydrophobicity of amphiphiles on the adsorption process. The characterizations were carried out using Rheometry, Field Emission Scanning Electron Microscopy (FESEM), Infrared Spectroscopy (IR), and Energy Dispersive X-ray Spectroscopy (EDX). Under optimized conditions, ALG-GEM and ALG-DDAB demonstrated highest maximum adsorption capacity (Qmax > 700 mgg−1). The adsorption data fitted well to pseudo-second order kinetic and Langmuir adsorption models, suggesting the involvement of chemisorption phenomena with notable contributions from pore diffusion. The effects of pH, initial dye concentration, adsorbent dose, temperature, and competing ions on the removal of MG were investigated. Interestingly, ALG-GEM beads exhibited an increase in adsorption capacity with rising pH and a subsequent decrease with increasing temperature, showcasing optimal adsorption at pH 7.0 and 25 °C. The study proposes that ALG beads modified with cationic surfactants with higher hydrophobicity could offer a promising avenue in wastewater treatment processes.

Partial Ligand Stripping from CsPbBr3 Nanocrystals Improves Their Performance in Light-Emitting Diodes.

Halide perovskite nanocrystals (NCs), specifically CsPbBr3, have attracted considerable interest due to their remarkable optical properties for optoelectronic devices. To achieve high-efficiency light-emitting diodes (LEDs) based on CsPbBr3 nanocrystals (NCs), it is crucial to optimize both their photoluminescence quantum yield (PLQY) and carrier transport properties when they are deposited to form films on substrates. While the exchange of native ligands with didodecyl dimethylammonium bromide (DDAB) ligand pairs has been successful in boosting their PLQY, dense DDAB coverage on the surface of NCs should impede carrier transport and limit device efficiency. Following our previous work, here, we use oleyl phosphonic acid (OLPA) as a selective stripping agent to remove a fraction of DDAB from the NC surface and demonstrate that such stripping enhances carrier transport while maintaining a high PLQY. Through systematic optimization of OLPA dosage, we significantly improve the performance of CsPbBr3 LEDs, achieving a maximum external quantum efficiency (EQE) of 15.1% at 516 nm and a maximum brightness of 5931 cd m-2. These findings underscore the potential of controlled ligand stripping to enhance the performance of CsPbBr3 NC-based optoelectronic devices.

Removal of perfluoroalkyl acids from aqueous media by surfactant-modified clinoptilolites.

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are environmentally persistent, bioaccumulating, and toxic compounds that have attracted global attention. It is challenging to reduce the residual concentrations of these compounds to safe discharge limits. In this study, batch experiments were performed to evaluate natural clinoptilolite and clinoptilolites modified (MC) with cetylpyridinium chloride (CPC-MC), didodecyldimethylammonium bromide (DDAB-MC), hexadecyltrimethylammonium bromide (HDTMA-MC), and tetramethylammonium chloride (TMA-MC) as cost-effective aqueous PFAS adsorbents. The removal capacities of the adsorbents for the majority of the PFASs decreased in the following order: DDAB-MC > CPC-MC ≫ modified natural clinoptilolite with hexadecyltrimethyl ammonium bromide (HDTMA-MC) ≫ modified natural clinoptilolite with tetramethylammonium chloride (TMA-MC) ≈ natural clinoptilolite modified with NaCl (NC). In particular, CPC-MC and DDAB-MC reduced PFASs concentration in 50μg/L by up to 98% for perfluorooctane sulphonate. Within 30min, CPC-MC (30.5μg/L) and DDAB-MC (32.1μg/L) met the PFOS water quality criterion of 36μg/L in inland surface waters. Both adsorbents met this criterion at the highest solution volume (40mL) and 0.125g/L (solid-to-liquid ratio of 1:8). PFASs with short hydrocarbon chains competed more for adsorption. PFASs with sulphonate functional groups were also adsorbed more than carboxyl groups in single- and multi-PFAS solutions. The modified surfaces of clinoptilolites controlled PFAS adsorption through hydrophobic and electrostatic interactions. PFAS removal with surfactant-modified clinoptilolites is cost-effective and protects aquatic environments by using surplus natural materials.

Enhanced Cyan Photoluminescence and Stability of CsPbBr3 Quantum Dots Via Surface Engineering for White Light‐Emitting Diodes

AbstractThe emission of cyan light (470‐500 nm) plays a vital role in the visible light spectrum and is essential for applications such as lighting, displays, and optical communication. Inorganic cesium lead bromide perovskite quantum dots (CsPbBr3 PQDs) have made significant progress in the field of luminescence materials and devices, however, the lack of techniques to obtain highly emissive and stable cyan‐emitting CsPbBr3 PQDs has limited their device applications. Here, it is demonstrated that the complete surface passivation by treatment of didodecyldimethylammonium bromide (DDAB) and lead bromide, which can enhance the photoluminescence and stability of cyan emitting CsPbBr3 PQDs. In particular, the photoluminescence quantum yield of CsPbBr3 QDs can be greatly improved from 10.5% to 83.8%. Through an effective PMMA passivation, the obtained stable and bright CsPbBr3 PQDs composite films as the cyan color converters can effectively emit the cyan light to fill the “cyan gap” of white light‐emitting diode (WLED). The color rendering index value of such WLED is remarkably enhanced from 73.6 to 82.5. This study paves the way for the application of PQD color converters in the next generation of full‐visible‐spectrum WLED lighting.

Colloidal Aziridinium Lead Bromide Quantum Dots.

The compositional engineering of lead-halide perovskite nanocrystals (NCs) via the A-site cation represents a lever to fine-tune their structural and electronic properties. However, the presently available chemical space remains minimal since, thus far, only three A-site cations have been reported to favor the formation of stable lead-halide perovskite NCs, i.e., Cs+, formamidinium (FA), and methylammonium (MA). Inspired by recent reports on bulk single crystals with aziridinium (AZ) as the A-site cation, we present a facile colloidal synthesis of AZPbBr3 NCs with a narrow size distribution and size tunability down to 4 nm, producing quantum dots (QDs) in the regime of strong quantum confinement. NMR and Raman spectroscopies confirm the stabilization of the AZ cations in the locally distorted cubic structure. AZPbBr3 QDs exhibit bright photoluminescence with quantum efficiencies of up to 80%. Stabilized with cationic and zwitterionic capping ligands, single AZPbBr3 QDs exhibit stable single-photon emission, which is another essential attribute of QDs. In particular, didodecyldimethylammonium bromide and 2-octyldodecyl-phosphoethanolamine ligands afford AZPbBr3 QDs with high spectral stability at both room and cryogenic temperatures, reduced blinking with a characteristic ON fraction larger than 85%, and high single-photon purity (g(2)(0) = 0.1), all comparable to the best-reported values for MAPbBr3 and FAPbBr3 QDs of the same size.