Isomeric polythiophene: a promising material for low voltage electronic devices.

In this investigation, we present empirical observations detailing the manifestation of substantial negative capacitance (NC), reaching up to -1 F, within iodine-doped isomeric polythiophene (IPTh-I2). NC observed in our case is not transient but stable enough to be measured for as long as the optimum concentration of the iodine dopant is available. In contrast, undoped isomeric polythiophene (IPTh) manifests a modest positive capacitance ranging from 30 to 60 µF. The concatenation of IPTh-I2 and IPTh in the series results in an augmentation of the total capacitance of the system (∼170 µF), exemplifying a characteristic feature of NC. Conversely, a bilayer configuration consisting of IPTh:IPTh exhibits a reduction in total capacitance by 38%. A notable amplification in the dielectric constant, escalating from 30 in IPTh to approximately 2000 in IPTh-I2, signifies extensive conformational and structural alterations arising from interactions between the doped polymer chain and various iodide species, attributing to the emergence of NC. Furthermore, we document a single-sided p-n junction diode with a low knee voltage (below 0.5 V) as a model device, illustrating the potential of IPTh as a promising material for the design and development of negative capacitance-based field-effect transistors. This research offers avenues for the scientific community to conceive low knee voltage-operating diodes, transistors, supercapacitors, and various other electronic devices based on all-organic semiconductors.

Impact of KOH Activation on Rice Husk Derived Porous Activated Carbon for Carbon Capture at Flue Gas alike Temperatures with High CO2/N2 Selectivity.

Metal-free porous activated carbon is an effective alternative to capture CO2 due to its high surface area and textural advantages. In this regard, the present research work explores a suitable method for producing activated porous carbon with a high specific surface area through a two-step reaction involving rice husk and KOH at 600 °C for 1 h to capture CO2. By varying the ratio of rice husk biomass to KOH, the texture and specific surface area of the activated porous carbon has been altered. A high surface area of ∼755 m2/g and a micropore volume of 0.243 cm3/g have been observed in the porous carbon produced with a KOH/biomass weight ratio of 3 (PAC2). Nitrogen contents in PAC1 and PAC2 were approximately 2.27 and 2.71 atom %, respectively. When compared with other materials, PAC2 has the highest CO2 adsorption capability, reaching up to 3.13 mmol/g at 0 °C and 1.55 mmol/g at 50 °C. The isosteric heat of adsorption confirms the presence of both physisorption and chemisorption. The materials turn out to be highly CO2/N2 selective, with the highest selectivity of 131, proving that the samples are potential materials for capturing CO2 from flue gases. These findings unequivocally show that porous activated carbon can be used to make CO2 adsorption efficient, inexpensive, and, more importantly, extremely effective.

Synthesis, characterization and electro-conducting study of isomeric polythiophene.

Herein we have reported for the first time a one-pot, one step methodology to synthesize isomeric polythiophene (IPTh) possessing 2,2, 2,4 and 5,4 linkages. The method of polymerization of thiophene to IPTh involved reacting thiophene with DDQ in the presence of concentrated H2SO4 at 40 °C and the polymerization is completed in 10 minutes. The synthesized IPTh was characterized by various spectroscopic and microscopic techniques. The formation of polaron and bipolaron in an iodine doped sample (IPTh-I2) has been confirmed by IR, Raman and UV-Vis spectra. The electrical conductivity of the synthesized IPTh and IPTh-I2 have been studied by impedance spectroscopy and found to be ∼10-5 and 10-3 S cm-1 respectively. IPTh exhibits an excellent thermal stability up to 150 °C, and low optical band gap of 3.49 eV suitable for photovoltaic applications. The weight average molecular weight of IPTh has been found to be 18.636 kDa, and it has a better post functionalization capability and hence wider scope than polythiophene (PTh).

Underutilized finger millet crop for starch extraction, characterization, and utilization in the development of flexible thin film.

Three different varieties of finger millets (VL-315, VL-324, and VL-347) cultivated in Uttrakhand, India, were used to extract high purity starch using the alkali soaking approach and investigated physicochemical and structural properties. VL-315, VL-324, and VL-347, contain 78 ± 0.35%, 79 ± 0.35%, and 87 ± 0.35% starch, respectively, of which 39.03 ± 0.35%, 37.2 ± 0.35%, and 33.5 ± 0.35% are the amylose contents, respectively. Chemical composition analysis exhibited the level of ash and moisture content in the dry basis of 0.0031 ± 0.01% to 0.035 ± 0.05%, and 12.52 ± 0.8% to 12.92 ± 0.2%, respectively. The solubility and swelling range of VL-315 is 1.3-4.3% and 16.54-10.3 (g/g), respectively, which significantly differ from VL-324 and VL-347. XRD analysis revealed that extracted starch showed a typical A-type crystalline network with a crystallinity range of 17.7-19.3%, which remarkably influenced retro gradation tendencies of starch. SEM demonstrated that extracted starch granules are polyhedral shape with a smooth surface. Finger millet starch has enormous potential in the development of starch-based edible film and coating on food items. In the present work, extracted finger millet starch was studied with the aim of developing a thin and flexible food packaging film. From the results, it was observed that the fabricated films had excellent functional properties, including solubility, swelling index, and water vapor permeability, which could eliminate petroleum-based packaging materials, and gives food materials an extra shelf life, and improve overall food quality.

A review on ex situ mineral carbonation.

The increased CO2 quantities in the environment have led to many harmful effects. Therefore, it is very important to decrease the CO2 levels in the environment. CO2 capture along with safe and permanent storage using mineral CO2 sequestration method can play an important role to reduce carbon emissions into the environment. Mineral sequestration is a stable storage method that provides long-term storage and an appropriate substitute for the more popular geological storage method. The process is most suited for places where there is a lack of underground cavities for underground geological storage. Minerals rich in Ca and Mg are used predominantly in carbonation reactions. In addition, those alkaline wastes that are rich in Mg and Ca such as cement waste, steel slag and many process ashes can also be employed in CO2 sequestration. Mineral carbonation could be used for the sequestration of billions of tonnes of CO2 every year. However, various drawbacks related to mineral carbonation still need to be addressed, such as resolving the slow rate of reactions, necessity of large amounts of feedstock, decreasing the high overall cost of CO2 sequestration and reducing the huge energy requirements to accelerate the carbonation reaction. This study explores a number of carbonation methods, parameters that control the process and future potential applications of carbonated products.

Dissolution of steel slags in aqueous media.

Steel slag is a major industrial waste in steel industries, and its dissolution behavior in water needs to be characterized in the larger context of its potential use as an agent for sequestering CO2. For this purpose, a small closed system batch reactor was used to conduct the dissolution of steel slags in an aqueous medium under various dissolution conditions. In this study, two different types of steel slags were procured from steel plants in India, having diverse structural features, mineralogical compositions, and particle sizes. The experiment was performed at different temperatures for 240 h of dissolution at atmospheric pressure. The dissolution rates of major and minor slag elements were quantified through liquid-phase elemental analysis using an inductively coupled plasma atomic emission spectroscopy at different time intervals. Advanced analytical techniques such as field emission gun-scanning electron microscope, energy-dispersive X-ray, BET, and XRD were also used to analyze mineralogical and structural changes in the slag particles. High dissolution of slags was observed irrespective of the particle size distribution, which suggests high carbonation potential. Concentrations of toxic heavy metals in the leachate were far below maximum acceptable limits. Thus, the present study investigates the dissolution behavior of different mineral ions of steel slag in aqueous media in light of its potential application in CO2 sequestration.

Experimental study of dissolution of minerals and CO2 sequestration in steel slag.

This study strives to achieve a substantial amount of steel slag carbonation without using any harmful chemicals. For this purpose, experiments were performed in an aqueous medium, in a semi-batch reactor, to investigate the effect of varying reaction conditions during the steel slag CO2 sequestration process. Further, studying the effect of dissolution on carbonation reactions and the mineralogical changes that subsequently occur within the slag helps provide insight into the parameters that ultimately have an impact on the carbonation rate as well the magnitude of the impact.