Isopropanol Research Articles

Correlating Molecular Precursor Interactions with Device Performance in Solution-Processed Cu2ZnSn(S,Se)4 Thin-Film Solar Cells.

Research efforts aimed at improving the crystal quality of solution-processed Cu2ZnSn(S,Se)4 (CZTSSe) absorbers have largely employed delicate pre- and postprocessing strategies, such as multistep selenization, heat treatment in mixed chalcogen atmospheres, and multinary extrinsic doping that are often complex and difficult to reproduce. On the other hand, understanding and tuning chemical interactions in precursor inks prior to the thin-film deposition have received significantly less attention. Herein, we show for the first time how the complexation of metallic and chalcogen precursors in solution have a stark influence on the crystallization and optoelectronic quality of CZTSSe absorbers. By varying thiourea to metal cation ratios (TU/M) in dimethylformamide (DMF) and isopropyl alcohol (IPA)-based inks, we observed the formation of nanoscale metal-organic complexes and submicron size aggregates which play a key role in the morphology of the precursor layers obtained by spin-coating and drying steps. We also identify the primary cations in the complexation and assembling processes in solution. The morphology of the precursor film, in turn, has an important effect on grain growth and film absorber structure after the reactive annealing in the presence of Se. Finally, we establish a link between metal complexes in precursor solutions and device performance, with power conversion efficiency increasing from approximately 2 to 8% depending on the TU/M and Cu/(Zn + Sn) ratios.

Comparison of different approaches to texturing monocrystalline silicon wafers for solar cell applications

Texturing the surface of crystalline silicon wafers is a very important step in the production of high-efficiency solar cells. Alkaline texturing creates pyramids on the silicon surface, lowering surface reflectivity and improving light trapping in solar cells. This article provides a comparative evaluation of various wet texturing methods using alkaline solutions with or without additives commonly known as surfactants. One method uses sodium hydroxide (NaOH) and isopropyl alcohol (IPA) to create a surface with a height of about 4.5 μm by texturing for about 30 min, while the other method uses potassium hydroxide (KOH) and other additions known as additives. Texturing was performed using chemicals for only 15 min to create a surface shape with a height of approximately 3.5 μm. Additionally, the two solutions showed reflectance of 8.01 % or 12.1 % in 400–1100 nm, respectively. Both processes used alkaline etching at 80 °C for saw damage removal (SDR) before texturing. These processes have also been investigated in terms of removing potential organic contaminants from surfaces. Characterization techniques used throughout the investigation included optical microscopy, surface reflectance measurements, scanning electron microscopy (SEM), and electron dispersive spectroscopy (EDS). The purpose of this study is to confirm through experiments which texturing techniques are more suitable for mass production and to develop time- and cost-effective texturing techniques for industrial production of high-throughput, high-efficiency solar cells.

Directed Hydrogen Atom Transfer for Selective Reactions of Polyenols.

Directed hydrogen atom transfer to alkenes is described. The process is catalyzed by iron complexes and allows for the site-selective hydrofunctionalization of polyenols. Experimental data suggest that coordination of the hydroxy group to the iron hydride intermediate plays an important role in preferential engagement of the allylic alcohol motif and provides a new basis for selectivity in radical hydrofunctionalization events. As a proof of concept, β- and γ-amino alcohols are prepared from the corresponding polyenols in a selective manner.

Hydroxyapatite synthesis and characterization from waste animal bones and natural sources for biomedical applications.

Hydroxyapatites (HAps) synthesized from waste animal bones have recently gained attention due to their outstanding properties. This is because there is a need to fabricate scaffolds with desirable mechanical strength, ability to withstand high temperatures, and insoluble in solvents such as water, acetone, ethanol, and isopropyl alcohol. This study is an extensive summary of many articles on the routes of synthesis/preparation of HAp, and the optimum processing parameter, and the biomedical application areas, such as: drug administration, dental implants, bone tissue engineering, orthopedic implant coatings, and tissue regeneration/wound healing. A broad catalog of the synthesis methods (and combination methods), temperature/time, shape/size, and the calcium-to-phosphorous (Ca/P) value of diverse waste animal bone sources were reported. The alkaline hydrolysis method is proposed to be suitable for synthesizing HAp from natural sources due to the technique's ability to produce intrinsic HAp. The method is also preferred to the calcination method owing to the phase transformation that takes place at high temperatures during calcinations. However, calcinations aid in removing impurities and germs during heating at high temperatures. When compared to calcination technique, alkaline hydrolysis method results in crystalline HAp; the higher degree of crystallinity is disadvantageous to HAp bioactivity. In addition, the standardization and removal of impurities and contaminants, thorough biocompatibility to ensure clinical safety of the HAp to the human body, and improvement of the mechanical strength and toughness to match specific requirements for the various biomedical applications are the important areas for future studies.

Utilization of Waste Banana Peels and Corn Cobs as Substrates in Neurospora sitophila Fermentation for Production of Natural Yellow Dyes

In the current situation, biomass gasification has become a major interest in producing clean energy and green chemicals. By gasification, the biomass can be converted to synthetic gas (syngas) for many purposes. However, syngas with high tar content can cause pipeline fouling and disturb the operation of downstream equipment. To reduce tar content, a two-series wet scrubber was installed for syngas cleaning produced by palm kernel shell gasification. Firstly, the gasification is operated at a temperature range of 500 – 600oC and 700 – 800oC to determine the conditions where the lowest tar syngas is produced. After that, the wet scrubber is installed with a variety of solvents including isopropyl alcohol, water, used cooking oil, and used lubricating oil. The results show that the lowest tar syngas was produced at a temperature of 800oC with a tar yield of 0.165 g/kg biomass. Meanwhile, in the same condition, isopropyl alcohol delivers the most substantial impact on tar removal efficiency, whereas used lubricating oil results in less impact. The use of isopropyl alcohol resulted in 99.25% tar removal effectiveness while lubricating oil yielded just 50.32%.

Tar Removal of Palm Kernel Shell Syngas using Wet Scrubber

In the current situation, biomass gasification has become a major interest in producing clean energy and green chemicals. By gasification, the biomass can be converted to synthetic gas (syngas) for many purposes. However, syngas with high tar content can cause pipeline fouling and disturb the operation of downstream equipment. To reduce tar content, a two-series wet scrubber was installed for syngas cleaning produced by palm kernel shell gasification. Firstly, the gasification is operated at a temperature range of 500 – 600oC and 700 – 800oC to determine the conditions where the lowest tar syngas is produced. After that, the wet scrubber is installed with a variety of solvents including isopropyl alcohol, water, used cooking oil, and used lubricating oil. The results show that the lowest tar syngas was produced at a temperature of 800oC with a tar yield of 0.165 g/kg biomass. Meanwhile, in the same condition, isopropyl alcohol delivers the most substantial impact on tar removal efficiency, whereas used lubricating oil results in less impact. The use of isopropyl alcohol resulted in 99.25% tar removal effectiveness while lubricating oil yielded just 50.32%.

Singlet oxygen species induced by colloidal crystalline carbon nitride induced for efficient H2O2 synthesis with in situ antibacterial effect

Solar-driven hydrogen (H2) and hydrogen peroxide (H2O2) generation over visible-light responsive carbon nitride (CN) photocatalysts for in situ efficient sterilization is a promising and eco-friendly strategy. Herein, a colloidal potassium-ion (K+) intercalated crystalline CN nanosheets (KCCN) photocatalyst was constructed for boosting synergetic H2O2 synthesis with isopropanol (IPA) oxidation and in situ antibacterial effect. The surface hydroxyl (−OH) and cyano (−CN) groups induced by molten salt (KCl)-assisted thermal treatments contributed to the colloidal nature of CN, facilitating for high wettability of KCCN in aqueous solution to gain active hydrogen (H+) from water sustainably. Meaningfully, the enhanced high-energy singlet oxygen species (1O2) produced by KCNN-2 were verified by electron paramagnetic resonance (EPR) and 9,10-anthracenediyl-bis(methylene)-dimalonic acid (ABDA)-fluorescent probe, significantly contributing to H2O2 production and antibacterial effect. Consequently, the optimal KCCN-2 exhibited a much enhanced H2 generation of 4.11 mmol g−1 h−1, and H2O2 production activity of 1.82 mmol L−1 h−1 with acetone yield rate of 47.3 mmol g−1 h−1 under visible-light (λ > 420 nm) irradiation in 10 vol% IPA solution. The in-situ generated H2O2 can be activated to produce reactive oxygen species (ROS), especially 1O2, to effectively kill the Escherichia coli, reaching an improved an antibacterial rate of 89.7% under stimulated sunlight irradiation in 1 h. This work could offer a new insight into the photoinduced ROS for aqueous H2O2 photosynthesis and antibacterial application.

A Silica Nano-Additive's Impact on the Performance and Emissions of a Diesel Engine Using DTBP Blended Low Viscous Waste Orange Peel Oil

<p>In the current study, the effect of silicon dioxide (SiO2) nano-additive mixed with Orange peel oil (OPO) as Biodiesel was investigated in relation to the operation and emission characteristics of a diesel engine. Orange peel oil was extracted from the orange Peel waste by using steam distillation method. The addition of Di-tetra-butyl-peroxide (DTBP) as a cetane booster is a novel strategy that has been attempted to improve the ignition patterns of OPO. The properties of customized fuel produced with a varying volume percentage DTBP and SiO2in 25,50 and 75 ppm in OPO were determined and compared to those of diesel. Uniform blending of nano-additives + DTBP with OPO is achieved by ultrasonication and isopropyl alcohol is used as a surfactant in order to stabilise the nano-additives. The physical and chemical characteristics of samples of pure and mixed fuel were identified and found in accordance with ASTM standards. Under varied loading conditions, the performance and emissions characteristics of various samples of fuel were studied. Addition of SiO2 nano-additive + DTBP increased the brake thermal efficiency (BTE) by 3.20-8.37% while decreasing brake specific fuel consumption (BSFC) by 4.18-11.25%. Carbon monoxide (CO), hydrocarbon (HC),nitrogen oxides (NOx) and smoke emissions were reduced by 5.61-12.84%, 9.65-19.05%, 0.89-7.71%, and 10.11-19.71%, respectively, when orange peel oil is blended with SiO2 and DTBP, and the mixture 10DTBP/90OPO -50SiO2 is found best comparable to ordinary diesel.</p>

Brønsted Acid Catalyzed Dehydroxylative Cyanation of Benzylic Alcohols with Trimethylsilyl Cyanide Using 1,1,1,3,3,3‐Hexafluoro‐2‐propanol as a Solvent

AbstractA concise and direct Brønsted acid catalyzed cyanation of secondary and tertiary benzylic and allylic alcohols has been developed using trimethylsilyl cyanide (TMSCN) as a cyanide source and 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) as a solvent. The present transition‐metal‐free catalytic process is operationally simple to perform under “open‐flask” conditions and is applicable to the preparation of a number of α‐arylacetonitriles as well as late‐stage material transformations. The effectiveness of the present protocol was further demonstrated by the first enantioselective synthesis and determination of the absolute configuration of verimol F.

Iron(ΙΙΙ) Catalyzed Aerobic Cα–Cβ Cleavage of Allylic Alcohols

The regiospecific Cα–Cβ cleavage of allylic alcohols under modified aerobic Mukaiyama hydration conditions is presented. The new methodology can be regarded as an equivalent of a two‐step process, a typical hydration of the parent allylic alcohol followed by a 1,2‐diol cleavage. A broad scope of substrates, both cyclic and acyclic, are applicable, thus introducing substantial structural modification to the core, especially of the former type of substrates. Mechanistic investigation of the reaction reveals the importance of the nearby hydroxyl group for the deviation from the typical Mukaiyama hydration pathway.

All‐Solution‐Processed Top‐Emitting InP Quantum Dot Light‐Emitting Diode with Polyethylenimine Interfacial Layer

AbstractRecent studies on top‐emitting structure, which is designed to enhance the color purity and outcoupling efficiency of quantum‐dot light‐emitting diodes (QLEDs), employ commercially unviable methods owing to limited options for applying the hole injection layer through solution processes on the bottom electrode. In this study, all‐solution‐processable conventional top‐emitting QLEDs (TQLEDs) are successfully fabricated by introducing a polyethylenimine (PEI) interlayer, doping isopropyl alcohol (IPA) into the hole‐injection layer (poly (3,4‐ethylenedioxythiophene):poly(4‐styrenesulfonate), PEDOT:PSS), and using the dynamic spin‐coating method. The increased hole injection resulting from the tuned anode‐HIL interface by the PEI and IPA‐doped HIL, coupled with the enhanced outcoupling efficiency and full width at half maximum (FWHM) derived from the optimized cavity length through simulation, realizes a red InP QLED with high efficiency and color purity. The optimized TQLED exhibits a maximum current efficiency and FWHM of 28.04 cd A−1 and 36 nm, respectively, which are threefold higher and 8 nm narrower than those of bottom‐emitting QLEDs, marking the highest current efficiency ever reported for top‐emitting red InP QLEDs.

Ambient-atmosphere fabricated perovskite solar cells with formamidinium iodide passivation for enhanced light absorption

The exceptional photoelectric characteristics and high conversion efficiency have positioned metal halide perovskite as a significant breakthrough in recent thin-film photovoltaic technology. Despite these advantages, perovskite crystalline lattices often contain defects like interstitials, vacancies, and impurities at grain boundaries and surfaces, along with dangling bonds, contributing to the nonradiative recombination processes among photocarriers, which hamper device performance and stability. In this context, we present a simple method to mitigate electronic defects occurring at the interface between perovskite (Cs0.17FA0.83Pb(I0.83Br0.17)3 films and the hole transport layer by applying organic salt, namely formamidinium iodide (FAI), in an eco-friendly isopropanol (IPA) antisolvent to treat the perovskite surface. Incorporating FAI reduces grain boundaries, enhances carrier transportation, and boosts power conversion efficiency from 13.59 % to 15.10 % under 1 sun measurement with an active area of 0.09 cm2. Similarly, under 1000 lx illumination, efficiency improves from 26.70 % to 28.69 %, with enhanced stability. This study offers a cost-effective and low-temperature method via the utilization of carbon electrodes to fabricate highly efficient planar perovskite solar cells under an air atmosphere, showcasing the potential for stable and economically viable photovoltaic solutions.

Engineered PEI-WS2 nanocomposite membranes for highly efficient pervaporation of water/isopropanol mixture

In this study, we present a novel approach to enhance pervaporation (PV) separation processes by addressing the challenge of membrane swelling due to organic aqueous solutions in polyelectrolyte composite systems. By integrating tungsten disulfide (WS2) and polyethyleneimine (PEI) into the membrane matrix, we synthesized a series of polyelectrolyte complex composite membranes on a modified polyacrylonitrile substrate. The unique interplay of WS2′s van der Waals forces and PEI's cationic attributes imparts enhanced structural stability and swelling resistance, culminating in a significant elevation of separation efficiency. The morphological and physicochemical properties of the membranes were meticulously characterized through scanning electron microscopy, atomic force microscopy, water contact angle measurements, and attenuated total reflection fourier transform infrared spectroscopy. In our pervaporation experiments, these membranes exhibited exceptional proficiency, separating a 70 wt% isopropyl alcohol aqueous solution under ambient conditions (25 °C, pH 7) with a fine-tuned PEI-WS2 ratio and concentration. The membranes achieved a permeation flux of 1380.86 g·m−2·h−1 and delivered a permeate with a water concentration of 99.71 wt%, underscoring their suitability for high-purity separations. Moreover, the membranes displayed consistent performance over extended operational periods, underscoring their robustness and durability. These results not only reinforce the potential of these membranes for industrial-scale separation tasks but also set the stage for further exploration into polyelectrolyte complex composites within the field of membrane science.

Enantioselective Synthesis of Antifungal Agent Voriconazole via Asymmetric Epoxidation of Tetrasubstituted (Z)‐Alkene

AbstractA concise asymmetric synthesis of triazole antifungal agent voriconazole is described. Salient features of this synthesis include a LiOH‐controlled highly stereospecific formation of (Z)‐enol triflate from 2‐difluorobenzene acetoacetate to access the crucial tetrasubstituted (Z)‐allylic alcohol, and a highly enantioselective VO(OiPr)3/BHA ligand‐catalyzed epoxidation to construct the critical contiguous carbon stereocenters in a single step.

Mechanistic study of cefixime degradation with an atmospheric air dielectric barrier discharge – Influence of radical scavengers and metal ion catalyst

The ineffective removal of antibiotic residues and their metabolites by conventional wastewater treatment setups lead to their continuous discharge into the environment, causing risks to both aquatic life and human health. This study explored the use of a non-thermal plasma (NTP) generated by atmospheric air for the degradation of cefixime (CFX), a widely consumed and recalcitrant antibiotic. This study achieved a complete degradation of CFX using an NTP technology in 8 min treatment time at 6 kV and 20 kHz applied AC voltage and frequency, respectively using a high voltage alternating current power supply unit. An energy yield of 0.42 g/kWh was estimated. The degradation of the pollutant was influenced by solution flow rate, applied voltage and the solution characteristics. Five degradation by-products were identified based on quadrupole time-of-flight (Q-TOF) mass spectrum (MS) analysis and a possible degradation pathway for the pollutant was proposed. Also, radical scavenger experiments were set up to understand the specific chemical species facilitating CFX degradation. The effect of Fe2+ catalyst on the degradation of CFX was investigated in the aqueous solution. This low-cost metal ion catalyst has been known to improve the degradation of organic compounds by facilitating the oxidizing power of H2O2. Considering this, a new idea was examined in this study which was the degradation of the antibiotic in the presence of both Fe2+ catalyst and some radical scavengers (iso-propyl alcohol – IPA, tert-butyl alcohol – TBA, and sodium hydrogen carbonate – NaHCO3). When Fe2+ was introduced into CFX solutions containing TBA, IPA and NaHCO3, respectively, the degradation and kinetics increased by at least 33 %. In these mixed additives, the degradation of the pollutant was enhanced by the consumption of H2O2.

Optimization of performance and emission of a diesel engine fueled with isopropyl alcohol Blends: A comparative ANN-GA and RSM-HCO application

This study focuses on optimizing the operating parameters of a diesel engine fueled by diesel-isopropyl alcohol blends, with the aim of enhancing engine performance and minimizing emissions. Using data collected from 144 experimental runs, predictive models were developed utilizing artificial neural networks (ANN) and response surface methodology (RSM). The models exhibited impressive accuracy, with an average absolute percentage error below 2 % for each parameter and an R2 value exceeding 0.99. Subsequently, these models were optimized using genetic algorithm (GA) and hill climbing algorithm (HCO) to identify the optimal engine operating conditions. The results indicate that both ANN-GA and RSM-HCO models exhibit satisfactory accuracy in predicting engine parameters. The ANN-GA model demonstrated an average deviation of 2.9 % from experimental data, while the RSM-HCO model exhibited an average deviation of 5.4 %. Both optimization results indicated that, in an emissions-focused approach, desirability above 0.9 could be achieved with isopropyl alcohol-diesel blends and high engine speeds, such as 2600–2700 rpm, with a 3.5 bar engine load, resulting in low emission values and high engine performance.

Highly Regio- and Stereoselective Dehydration of Allylic Alcohols to Conjugated Dienes via 1,4-syn-Elimination with H2 Evolution.

Dehydration of alcohols is one of the most fundamental transformations in the organic chemistry class and one of the most widely used methods for producing alkenes in synthetic research. Numerous methods and reagents have been developed to control the regio- and stereoselectivity as well as the dehydration efficiency of normal alcohols. Despite these achievements, regio- and stereoselective and predictable dehydration of allylic alcohol has seldom been reported, except for limited substrates with a native preferred elimination position, as a result of the challenges that many potential dienes could be formed via 1,2- or 1,4-syn- or anti-elimination. Here, we report a tBuOK/potassium 2,2-difluoroacetate-mediated 1,4-syn-dehydration of allylic alcohol for the synthesis of regio- and stereodefined conjugated dienes via an in situ generated directing group strategy. This reaction exhibits a broad substrate scope and good functional group compatibility for primary-tertiary alcohols. The simple and scalable (up to 0.6 mol) procedure with readily available and inexpensive reagents makes it a practical method for conjugated diene synthesis. Mechanistic studies reveal that an acetate with tert-butoxide and allyloxide acetal moiety is formed as an intermediate, in which the acetate and the acetal act as the directing group for the base-promoted elimination. An unusual H2 evolution is also involved in the reaction.

Cloud chamber using Peltier cooling

The design of a simple, compact, inexpensive cloud chamber is described and examples of particle tracks from cosmic rays and a radioactive sample are shown. A temperature gradient is established in the chamber through the use of a simple heater at the top and Peltier modules at the base, eliminating the need for dry ice. Using a few millilitres of isopropyl alcohol it starts to show particle tracks a few minutes after being switched on and operates for over two hours without any intervention. The cloud chamber is constructed using components that can be readily obtained at a total cost of about £40.

Experimental and Theoretical Study on Electron Ionization and Fragmentation of Propylene Oxide─the First Chiral Molecule Detected in the Interstellar Medium.

Propylene oxide, CH3CHOCH2, is the first chiral molecule detected in space and the third C3 oxide detected toward the Sagittarius B2 (Sgr B2 (N)) molecular cloud, the others being propanal, CH3CH2CHO, and acetone, (CH3)2CO. With homochirality being ubiquitous in the building blocks of living matter, the formation and decay paths of propylene oxide in space are of specific interest. Motivated by the significant role of photo- and secondary electrons in astrochemistry, we have studied electron ionization and fragmentation of propylene oxide. Ion appearance energies are determined and compared to threshold values for the respective processes calculated at the G4MP2 level of theory, and potential reaction pathways are computed at the DFT level of theory. Electron ionization is found to destabilize propylene oxide, leading to barrierless opening of the C1-C2 bond of the epoxy ring, hydrogen transfer, and fragmentation over the methyl vinyl ether or rupture of the C2-O bond of the epoxy ring and fragmentation of the allyl alcohol cation as an intermediate, rather than direct bond ruptures.

Cross-Double Deoxygenative Carbon–Carbon Bond Formation between Benzyl Benzoates and Allylic Alcohols

Cross-Double Deoxygenative Carbon–Carbon Bond Formation between Benzyl Benzoates and Allylic Alcohols