Phenyltrimethylammonium Bromide Research Articles

Enhanced Buried Interface Engineering for Efficient Inverted Perovskite Solar Cells Fabricated via Vapor-Solid Reaction.

Vapor-deposited inverted perovskite solar cells utilizing self-assembled monolayer (SAM) as hole transport material have gained significant attention for their high efficiencies and compatibility with silicon/perovskite monolithic tandem devices. However, as a small molecule, the SAM layer suffers low thermal tolerance in comparison with other metal oxide or polymers, rendering poor efficiency in solar device with high-temperature (> 160°C) fabricating procedures. In this study, a dual modification approach involving AlOx and F-doped phenyltrimethylammonium bromide (F-PTABr) layers is introduced to enhance the buried interface. The AlOx dielectric layer improves the interface contact and prevents the upward diffusion of SAM molecules during the vapor-solid reaction at 170°C, while the F-PTABr layer regulates crystal growth and reduces the interfacial defects. As a result, the AlOx/F-PTABr-treated perovskite film exhibits a homogeneous, pinhole-free morphology with improved crystal quality compared to the control films. This leads to a champion power conversion efficiency of 21.53% for the inverted perovskite solar cells. Moreover, the encapsulated devices maintained 90% of the initial efficiency after 600h of ageing at 85°C in air, demonstrating promising potential for silicon/perovskite tandem application.

Improved static membrane-free zinc‑bromine batteries by an efficient bromine complexing agent

Zinc‑bromine batteries (ZBBs) are very promising in distributed and household energy storage due to their high energy density and long lifetime. However, the disadvantages of existing zinc‑bromine flow batteries, including complicated structure, high cost for manufacturing and maintenance, limited their large-scale applications seriously. Additionally, polybromide anions during the charging process of ZBBs will result in the problem of self-discharge. Here, a static membrane-free ZBB (SMF-ZBB) structure has been proposed, in which the phenyl trimethyl ammonium bromide (PTMAB) works as a bromine complexing agent (BCA). Because PTMAB has a feature of strong polarity, it can be combined well with polybromide anions to reduce the self-discharge effectively. Furthermore, it can also reduce the internal resistance of electrolytes and improve the energy density of SMF-ZBB. Compared with the blank electrolyte, the coulombic efficiency (CE) of the battery with PTMAB addition was increased by 10 % at 20 mA/cm2. The CE with a value of 93.1 % can be well maintained even after >5000 cycles at 10 mA/cm2. The results show that the introduction of PTMAB into the electrolytes can improve the CE and energy efficiency (EE) effectively.

Quasi-2D bromide perovskite nanocrystals with narrow phase distribution prepared using ternary organic cations for sky-blue light-emitting diodes

Quasi-2D perovskite semiconductors can be created by introducing organic interlayer cations into 3D perovskites and possess large binding energy, superior stability, high luminance efficiency, and tunable bandgap, holding promising applications in blue-light emitting devices. Compared with mixed halide perovskites, quasi-2D bromide perovskites emit blue light with high color stability. However, multiple-phases usually co-exist in quasi-2D bromide perovskites, resulting in low color purity. In this work, three ammonium bromides, namely, 3-(trifluoromethyl)phenyltrimethylammonium bromide (F-PTABr), benzyltributylammonium bromide (BTBABr), and phenethylammonium bromide (PEABr), are employed to fabricate quasi-2D perovskite films with narrow phase distribution. PEA serves as the scaffold to stabilize the quasi-2D PEA2Csn-1PbnBr3n+1 perovskite structure and provides enough space to allow the F-PTA cation entering the interlayer, which further triggers the entrance of a larger BTBA cation into the interlayer. The large F-PTA and BTBA cations reduce the crystal size of the perovskite and narrow the phase distribution to n = 2. As a result, the photoluminescence spectrum of the PEA0.9F-PTA0.05BTBA0.05-based perovskite film becomes unimodal and blue-shifts from 498 to 484 nm compared with the film using the PEA1.0 cation. A sky-blue light-emitting diode with an external quantum efficiency of 0.6% is achieved using the PEA0.9F-PTA0.05BTBA0.05-based perovskite as the emitter. We, therefore, demonstrate a strategy to prepare phase narrow quasi-2D perovskites with improved color purity by introducing ternary organic cations into the quasi-2D perovskites and envisage that promising device performance can be achieved with a further dedicated structure design of the ammonium cations.

Spray‐Coated Colloidal Perovskite Quantum Dot Films for Highly Efficient Solar Cells

AbstractA fully automated spray‐coated technology with ultrathin‐film purification is exploited for the commercial large‐scale solution‐based processing of colloidal inorganic perovskite CsPbI3 quantum dot (QD) films toward solar cells. This process is in the air outside the glove box. To further improve the performance of QD solar cells, the short‐chain ligand of phenyltrimethylammonium bromide (PTABr) with a benzene group is introduced to partially substitute for the original long‐chain ligands of the colloidal QD surface (namely PTABr‐CsPbI3). This process not only enhances the carrier charge mobility within the QD film due to shortening length between adjacent QDs, but also passivates the halide vacancy defects of QD by Br− from PTABr. The colloidal QD solar cells show a power conversion efficiency (PCE) of 11.2% with an open voltage of 1.11 V, a short current density of 14.4 mA cm−2, and a fill factor of 0.70. Due to the hydrophobic surface chemistry of the PTABr–CsPbI3 film, the solar cell can maintain 80% of the initial PCE in ambient conditions for one month without any encapsulation. Such a low‐cost and efficient spray‐coating technology also offers an avenue to the film fabrication of colloidal nanocrystals for electronic devices.

Bright perovskite light-emitting diodes with improved film morphology and reduced trap density via surface passivation using quaternary ammonium salts

Abstract Organic-inorganic hybrid perovskite light-emitting diodes (PeLEDs) have emerged as one of the promising candidates for display and illumination devices with low-cost and high color purity. However, PeLEDs exhibit bad film uniformity and high defect density, which lead to poor device performance. Herein, we introduce an additive engineering strategy employing quaternary ammonium salts, namely benzyltrimethylammonium bromide (BTABr), phenyltrimethylammonium bromide (PTABr) and benzyltrimethylammonium chloride (BTACl), in the precursor solution to prepare uniform and dense MAPbBr3 perovskite films with reduced grain sizes. These quaternary ammonium salts, which have cations containing a bulky benzyl unit, are more effective at reducing the grain sizes of MAPbBr3 perovskites. More importantly, the BTABr additive performs a dual-passivation effect to the MAPbBr3, effectively reducing the trap density within the perovskite layer as well as the proportion of non-radiative recombination of PeLEDs, and balancing the charge injection. Consequently, PeLEDs incorporating a BTABr-modified MAPbBr3 layer exhibit a reduced turn-on voltage from 4.2 to 2.6 V, and the maximum luminance and current efficiency are enhanced from 3490 Cd/m2 and 0.24 Cd/A of the reference device to 12026 Cd/m2 and 1.27 Cd/A, respectively.

Bifunctional Stabilization of All-Inorganic α-CsPbI3 Perovskite for 17% Efficiency Photovoltaics.

The all-inorganic α-CsPbI3 perovskite with the most suitable band gap faces serious challenges of low phase stability and high moisture sensitivity. We discover that a simple phenyltrimethylammonium bromide (PTABr) post-treatment could achieve a bifunctional stabilization including both gradient Br doping (or alloying) and surface passivation. The PTABr treatment on CsPbI3 only induces less than 5 nm blue shift in UV-vis absorbance but significantly stabilize the perovskite phase with much better stability. Finally, the highly stable PTABr treated CsPbI3 based perovskite solar cells exhibit a reproducible photovoltaic performance with a champion efficiency up to 17.06% and stable output of 16.3%. Therefore, this one-step bifunctional stabilization of perovskite through gradient halide doping and surface organic cation passivation presents a novel and promising strategy to design stable and high performance all-inorganic lead halide.

Phenyltrimethylammonium Salts as Methylation Reagents in the Nickel‐Catalyzed Methylation of C−H Bonds

AbstractMethylation of C(sp2)−H bonds was achieved through the NiII‐catalyzed reaction of benzamides with phenyltrimethylammonium bromide or iodide as the source of the methyl group. The reaction has a broad scope and shows high functional‐group compatibility. The reaction is also applicable to the methylation of C(sp3)−H bonds in aliphatic amides.

Phenyltrimethylammonium Salts as Methylation Reagents in the Nickel-Catalyzed Methylation of C-H Bonds.

Methylation of C(sp(2))-H bonds was achieved through the Ni(II)-catalyzed reaction of benzamides with phenyltrimethylammonium bromide or iodide as the source of the methyl group. The reaction has a broad scope and shows high functional-group compatibility. The reaction is also applicable to the methylation of C(sp(3))-H bonds in aliphatic amides.

Adsorptive Desulfurization of Model Gasoline on Organic - Inorganic Modified Montmorillonite

The phenyl trimethyl ammonium bromide (PTMAB) and Keggin polyhydroxyl aluminum cations (Al13) as pillared agent and montmorillonite as the carrier, organic - inorganic pillared montmorillonite was prepared through sol-gel method to remove sulfur in model gasoline. The results showed when adsorption time was 1.5 h and reaction temperature was 40 °C, the maximum adsorption capacity of PTMAB-Al-MMT was 5.32 mg/g. The modified materials were characterized by X-ray diffraction, Nitrogen adsorption-desorption and NMR techniques to investigate the material structure and the adsorption mechanism. After the intercalation of PTMAB and Keggin Al13 in MMT, the interlayer d-spacing, specific surface and pore volume area increased to 1.10 nm, 41.23 m2 /g and 0.16cm3/g, respectively.

Removal of Pesticides by Organic Montmorillonite Composites

The removal of pesticides (quintozene, α-BHC, Aldrin and pp′-DDT) by phenyltrimethylammonium bromide (PTMAB) modified montmorillonites(PTMAB-MMT) was investigated. The results showed that these four kinds of pestcides have high affinity with PTMAB-MMT. The composites were characterized by FTIR and XRD. Further, the removal experiments of pesticides in ginseng extracts were carried out. The Ginsenosides were analyzed by high performance liquid chromatography/mass spectrometry showed that the loss of Ginsenosides was less than 4%. It can be concluded that the PTMAB-MMT is a promising material in pesticide pollution treatment

Combined modification of zeolite NaY by phenyl trimethyl ammonium bromide and potassium for ethylene gas adsorption

Zeolite NaY was co-modified with 0.5mM phenyl trimethyl ammonium bromide (PTAB) and 5.0mM KNO3. Three types of modification were employed and there were two successively modifications (K+/PTAB-zeolite NaY and PTAB/K+-zeolite NaY) and a simultaneous modification (PTAB+K+/zeolite NaY). The modified zeolites were characterized by surface area and pore size analysis, X-ray diffraction, and atomic emission spectroscopy. The XRD studies indicated that the modification did not lead to structural destruction. The surface area analysis indicated 10% of external surface area and 90% of internal surface area. The adsorptions of ethylene gas over these modified zeolites NaY were investigated. All of the three differently modified zeolites showed better ethylene adsorptivity after modification. The zeolite that displayed the best ethylene adsorptivity was the zeolite that was modified by the simultaneous modification method. The ethylene adsorption was raised from 82.5cm3g−1 for the unmodified to 116.6cm3g−1 for the simultaneously modified zeolite.

The Removal of 2-Phenylphenol from Aqueous Solution by Adsorption onto Organoclays

Abstract The adsorption of 2-phenylphenol onto organically pillared clays (a natural montmorillonite and a synthetic saponite) was investigated. Organoammonium salts used for the clay modification were trimethylphenylammonium bromide, 3-(trifluoromethyl)phenyltrimethylammonium bromide, and neostigmine bromide. All the organically pillared clays adsorbed 2-phenylphenol from water. The adsorbed amount of 2-phenylphenol was smaller as the cation-exchange capacity of host was larger, showing possible pore volume engineering.

Ethylene adsorption on cationic surfactant modified zeolite NaY

The ethylene adsorption isotherms of zeolite NaY and their cationic surfactant modifiers, phenyl trimethyl ammonium bromide (PTAB), octyl trimethyl ammonium bromide (OTAB), hexadecyl trimethyl ammonium bromide (HTAB) and dioctadecyl dimethyl ammonium bromide (DDAB), were investigated. Zeolite NaY was synthesized and modified by cationic surfactants in the concentration range 0.1–3.0 mM. The ethylene adsorption isotherms indicated that only zeolite modified with PTAB could significantly enhance the ethylene adsorption capacity. Zeolite NaY modified with 0.5 mM PTAB was the best adsorbent and could adsorb up to 111.19 cm 3 g −1 of ethylene which was equivalent to a 28.5% increase. The XRD results indicate that modification of zeolite NaY with small amount of cationic surfactants does not change the crystallinity of the starting zeolite. The elemental analysis indicated that the Si/Al ratio of synthesized zeolite NaY was close to 2. Surface area characterization showed that the BET surface area and micropore surface area of modified zeolite slightly decreased but the external surface area, pore volume and pore size diameter remained unchanged.

The removal of phenol from aqueous solutions by adsorption using surfactant-modified bentonite and kaolinite

The natural bentonite (BC) and kaolinite (KC) were modified with two surfactant of hexadecyltrimethylammonium bromide (HDTMA) and phenyltrimethylammonium bromide (PTMA) to form four kinds of organic-modified clays, i.e., HDTMA–bentonite (BHM), HDTMA–kaolinite (KHM), PTMA–bentonite (KPM) and PTMA–kaolinite (KPM). The modified minerals were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD) and FT-IR spectroscopy. The surface areas were determined using methylene blue adsorption method. Cation-exchange capacity (CEC) was estimated using an ethylenediamine complex of copper method and the modifier loading was calculated from the total carbon analysis. The ability of raw and organo-modified clays to remove phenol from aqueous solutions has been carried out as a function of contact time, pH and temperatures using a batch technique. The removal of phenol from aqueous solutions by modified clays seems to be more effective than unmodified samples. The adsorption capacity was found to increase with increasing temperature indication that the adsorptions were endothermic. The adsorption of phenol onto these clays was found to be increased by increasing of pH value and the adsorption patterns data are correlated well by Langmuir and Freundlich isotherm models and that the adsorption is physical in nature. The experimental data fitted very well with the pseudo-second-order kinetic model. The thermodynamic study of adsorption process showed that the adsorption of phenol with these six adsorbents was carried out spontaneously, and the process was endothermic in nature.

Effects of surfactants on the transport properties of redox species through Nafion ® membranes

Previous research in our group has employed tetraalkylammonium bromides to alter the micellar structure of Nafion ® membranes to affect flux of redox species through the membrane. However, research by Patist et al. has shown that maximum micellar stability occurs when the chain lengths of the both the main micellar component and the surfactant are the same in sodium dodecyl sulfate micelles (SDS). When considering the steric hindrance of large, spherical ammonium salts and the effect of chain length compatibility on micellar stability, it was determined that n-alkyltrimethylammonium and n-alkyltriethylammonium surfactants may be more favorable in altering the pore structure. This research focuses on mixture-casting Nafion ® with ammonium-based surfactants in order to form more stable Nafion ® membranes with larger pore structures and a less acidic environment that will be more biocompatible with entrapping dehydrogenase enzymes within the membrane. n-Alkyltriethylammonium and n-alkyltrimethylammonium surfactants decreased the number of available exchange sites to proton (proton exchange capacity) of the membrane and they altered the transport of redox species through the membrane. Phenyltrimethylammonium bromide treated Nafion ® membranes and triethylhexylammonium bromide treated Nafion ® membranes were found to successfully immobilize dehydrogenase enzymes while maintaining enzyme activity.

Association of Hydrotropes in Aqueous Solution Studied by Reaction Kinetics

The effect of added hydrotropes on the rates of neutral hydrolysis for 1-benzoyl-3-phenyl-1,2,4-triazole 1 has been studied, together with the concentration dependence of the 1H NMR spectra of the hydrotropes in aqueous solution. Hydrotropes include sodium 4-alkylbenzenesulfonates 2a - e, sodium 4-methoxybenzenesulfonate 2f, sodium 4-hydroxybenzenesulfonate 2g, cesium benzenesulfonate 3, benzamidinium chloride 4, phenyltrimethylammonium bromide 5a, and benzyltrimethylammonium bromide 5b. All hydrotropes, except 2g, induce strong rate-retarding effects, indicative of strong interactions with 1 and of remarkably strong hydrophobic interactions between aromatic moieties. Most hydrotropes show neither spectroscopic nor kinetic evidence for cooperative aggregation in the concentration range studied, i.e., from 0 to 1.4 mol kg-1. Cooperative aggregation is absent because the hydrophobic moieties are too small for hydrophobic interactions to overcome electrostatic repulsion. Lack of aggregation results in high availability of hydrophobic binding sites, thereby accounting for the high solubilizing power characteristic for hydrotropes. However, sodium 4-n-propylbenzenesulfonate 2d and sodium 4-nbutylbenzenesulfonate 2e show cooperative self-association forming highly dynamic loose micellar-type structures.