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We propose the possibility of using chitosan-modified magnetic biochar (CMBC) as a potential green material for treating heavy metals (HMs) that exist and persist in the environment. Different functional groups present on CMBC have been studied by surface analyses such as energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Herein, Fe serves not only as a contributor to magnetism but also as a facilitator in the formation of bonds with Pb(II). The adsorption efficiency of Pb(II) by CMBC (1 % w/v) reached to ∼97.6 % in 60 min. With 200 ppm at initial Pb(II) concentration, CMBC showed an adsorption capacity of ∼88.75 mg·g−1. The adsorption mechanism of Pb(II) by CMBC was consistent with the pseudo-second-order kinetic model with R2 = 0.9997. During the adsorption of Pb(II) by CMBC, Langmuir isotherms delivered R2 = 0.9993 which was larger than the R2 = 0.9882 of Freundlich isotherm, indicating that Pb(II) adsorption mainly occurred on the surface of CMBC with the interaction between Pb(II) and functional groups. The adsorption efficiency of soluble Pb (Pb in soil) by CMBC reached ∼24.6 % after 5 days and ∼27 % after 7 days. This finding underscores that CMBC is capable of effectively removing HMs, such as Pb, in both aqueous and soil environments.

A sensor can be called ideal or perfect if it is enriched with certain characteristics viz., superior detections range, high sensitivity, selectivity, resolution, reproducibility, repeatability, and response time with good flow. Recently, biosensors made of nanoparticles (NPs) have gained very high popularity due to their excellent applications in nearly all the fields of science and technology. The use of NPs in the biosensor is usually done to fill the gap between the converter and the bioreceptor, which is at the nanoscale. Simultaneously the uses of NPs and electrochemical techniques have led to the emergence of biosensors with high sensitivity and decomposition power. This review summarizes the development of biosensors made of NPssuch as noble metal NPs and metal oxide NPs, nanowires (NWs), nanorods (NRs), carbon nanotubes (CNTs), quantum dots (QDs), and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

Quantum dot solar cells have received significant attention in comparison to standard solar cells because of their hybrid nature, low production costs, and higher power conversion efficiency. Although quantum dot solar cells (QDSCs) have several benefits over ordinary solar cells, their performance lags due to carrier combination within the quasi-neutral region (QNR). The electron transport layer (ETL) and hole transport layer (HTL) are the two layers that have the most effect on QDSC performance. This numerical analysis is carried out by using the Solar Cell Capacitance Simulator-1 dimensional software (SCAPS-1D). In this paper, the optimization of two different device structure investigations is performed. In this proposed device structure, WS2 and IGZO are used as two ETL, CdS is used as a buffer layer, Sb2Se3 is used as an absorber layer, and PbS as HTL. Initially, the optimization of the device has been performed, followed by depth analysis of the doping densities. Resistance analysis is also performed to illustrate the effect of resistance on the device. Further, the impact of temperature on the device parameters is also represented, followed by a contour plot between thickness and bandgap for both devices. The impact of the series and shunt resistance on the performance of the solar cell is investigated. The effect of temperature is studied further, and it is observed that the solar device is temperature-sensitive. Finally, the optimized performance with IGZO ETL with PCE of 20.94% is achieved.

In this study, well-defined tungsten oxide (WO3) nanowall (NW) thin films were synthesized via a controlled hot filament chemical vapor deposition (HFCVD) technique and applied for electrochemical detection of methylamine toxic substances. Herein, for the thin-film growth by HFCVD, the temperature of tungsten (W) wire was held constant at ~1450 °C and gasification was performed by heating of W wire using varied substrate temperatures ranging from 350 °C to 450 °C. At an optimized growth temperature of 400 °C, well-defined and extremely dense WO3 nanowall-like structures were developed on a Si substrate. Structural, crystallographic, and compositional characterizations confirmed that the deposited WO3 thin films possessed monoclinic crystal structures of high crystal quality. For electrochemical sensing applications, WO3 NW thin film was used as an electrode, and cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were measured with a wide concentration range of 20 μM~1 mM of methylamine. The fabricated electrochemical sensor achieved a sensitivity of ~183.65 μA mM−1 cm−2, a limit of detection (LOD) of ~20 μM and a quick response time of 10 s. Thus, the fabricated electrochemical sensor exhibited promising detection of methylamine with considerable stability and reproducibility.

Risedronate sodium (RIS) exhibits limited bioavailability and undesirable gastrointestinal effects when administered orally, necessitating the development of an alternative formulation. In this study, mPEG-coated nanoparticles loaded with RIS-HA-TCS were created for osteoporosis treatment. Thiolated chitosan (TCS) was synthesized using chitosan and characterized using DSC and FTIR, with thiol immobilization assessed using Ellman’s reagent. RIS-HA nanoparticles were fabricated and conjugated with synthesized TCS. Fifteen batches of RIS-HA-TCS nanoparticles were designed using the Box–Behnken design process. The nanoparticles were formulated through the ionic gelation procedure, employing tripolyphosphate (TPP) as a crosslinking agent. In silico activity comparison of RIS and RIS-HA-TCS for farnesyl pyrophosphate synthetase enzyme demonstrated a higher binding affinity for RIS. The RIS-HA-TCS nanoparticles exhibited 85.4 ± 2.21% drug entrapment efficiency, a particle size of 252.1 ± 2.44 nm, and a polydispersity index of 0.2 ± 0.01. Further conjugation with mPEG resulted in a particle size of 264.9 ± 1.91 nm, a PDI of 0.120 ± 0.01, and an encapsulation efficiency of 91.1 ± 1.17%. TEM confirmed the spherical particle size of RIS-HA-TCS and RIS-HA-TCS-mPEG. In vitro release studies demonstrated significantly higher release for RIS-HS-TCS-mPEG (95.13 ± 4.64%) compared to RIS-HA-TCS (91.74 ± 5.13%), RIS suspension (56.12 ± 5.19%), and a marketed formulation (74.69 ± 3.98%). Ex vivo gut permeation studies revealed an apparent permeability of 0.5858 × 10−1 cm/min for RIS-HA-TCS-mPEG, surpassing RIS-HA-TCS (0.4011 × 10−4 cm/min), RIS suspension (0.2005 × 10−4 cm/min), and a marketed preparation (0.3401 × 10−4 cm/min).

This work describes the utilization of D-A-D type organic semiconductor, 4,4’-(benzo[c] [1,2,5]selenadiazole-4,7-diyl)bis(N,N-diphenylaniline), denoted as Se-2TPA, containing benzoselenadiazole (BSe) as acceptor core and end-capped with triphenylamine (TPA) donor units as donor materials in solar cells. Superlatively, the attachment of TPA donor moiety in BSe acceptor unit enlarged the conjugated system by extending the π-bonding which effectively tuned the optical and electrochemical properties of Se-2TPA. The bulk heterojunction organic solar cell (BHJ-OSCs) with configuration of ITO/cp-TiO2/Se-2TPA:PC61BM/Au showed power conversion efficiency (PCE) of ∼4.12% with short circuit current (Jsc) value of ∼11.28 mA/cm2, open circuit voltage (Voc) of ∼0.775 V and fill factor (FF) of ∼0.48. PCE significantly increased from ∼4.12% to ∼5.29% when 1,8-diiodooctane (DIO) was added as an additive in Se-2TPA:PC61BM blend which associated with less phase separation and improved the charge extraction. The fabricated BHJ-OSCs processed with 3% DIO, ITO/cp-TiO2/Se-2TPA:PC61BM/Au configuration displayed a long-term stability under air condition at an ambient temperature by maintaining ∼80% PCE for the duration of 30 days. The advantages of easy synthesis, low cost and promising cell performance supported Se-2TPA as successful organic semiconductor for BHJ-OSCs.

A simple hydrothermal synthesis approach was used to synthesize porous MgNiO2 Chrysanthemum Flowers (CFs) nanostructures and applied as a sensing electrode for quick detection of hazardous mercury (Hg2+ ions). The morphological, structural, and electrochemical properties of MgNiO2 CFs were investigated. The morphological characteristic of MgNiO2 CFs, with a specific surface area of 45.618 m2/g, demonstrated strong electrochemical characteristics, including cations in different oxidation states of Ni3+/Ni2+. Using a three-electrode system for electrochemical detection, the MgNiO2 CFs based electrode revealed a good correlation coefficient (R2) of ~0.9721, a limit of detection (LOD) of ~11.7 μM, a quick response time (10 s), and a sensitivity of 8.22 μA∙μM−1∙cm−2 for Hg2+ ions over a broad linear range of 10–100 μM. Moreover, the selectivity for Hg2+ ions in tap water and drinking water was determined, and a promising stability of 25 days by MgNiO2 CFs electrode was exhibited. The obtained results indicate that the developed MgNiO2 CFs are a promising electrode for detecting hazardous Hg2+ ions in water and have the potential to be commercialized in the future.

In this work, the structural, optical, morphological, and sensing features of tungsten oxide (WO3) thin film deposited on a silicon substrate via hot-filament chemical vapor deposition (HFCVD) are described. The experimental characterization tools, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible (UV-Vis), and Fourier transform infra-red (FTIR) spectroscopies, etc., were used to determine the properties of WO3 NPys thin films. The grown WO3 thin film illustrated closely packed porous pyramidal nanostructures (NPys) of improved grain size properties. The diffraction analysis revealed (100) and (200) of WO3 phases, suggesting the classic monoclinic crystal WO3 structure. HFCVD grown WO3 NPys thin film was employed as electro-active electrode for detecting ethylenediamine in 10 mL of 0.1 M phosphate buffer solution (PBS) by varying the ethylenediamine concentrations from 10 μM to 200 μM at room temperature. With a detection of limit (LOD) of ~9.56 μM, and a quick reaction time (10 s), the constructed chemical sensor achieved a high sensitivity of ~161.33 μA μM−1 cm−2. The durability test displayed an excellent stability of electrochemical sensor by maintaining over 90% sensitivity after 4 weeks of operation. This work provides a strategy for a facile preparation of WO3 NPys thin film electrode for sensor applications.

In order to develop new and effective donor materials, a planar donor-π-acceptor (D-π-A) type small organic molecule (SOM), 2-(4-fluorobenzoyl)-3-(5″-hexyl-[2,2′:5′,2″-terthiophen]-5-yl) acrylonitrile, named as H3T-4-FOP, was synthesized by the reaction of 4-fluorobenzoylacetonitrile (as acceptor unit) and hexyl terthiophene (as donor unit) derivatives. Promising optical, solubility, electronic and photovoltaic properties were observed for the H3T-4-FOP SOM. Significantly, the presence of 4-fluorobenzoylacetonitrile as an acceptor unit in H3T-4-FOP SOM tuned the optical band gap to ~2.01 eV and procured the reasonable energy levels as highest occupied molecular orbital (HOMO) of −5.27 eV and lowest unoccupied molecular orbital (LUMO) −3.26 eV. The synthesized H3T-4-FOP SOM was applied as a donor material to fabricate solution-processed bulk heterojunction organic solar cells (BHJ-OSCs) with an active layer of H3T-4-FOP: PC61BM (1:2, w/w) and was validated as having a good power conversion efficiency (PCE) of ~4.38%. Our studies clearly inspire for future designing of multifunctional groups containing the 4-fluorobenzoylacetonitrile based SOM for high performance BHJ-OSCs.

A new and effective planar D-π-A configured small organic molecule (SOM) of 2-5-(3,5-dimethoxystyryl)thiophen-2-yl)methylene)-1H-indene-1,3(2H)-dione, abbreviated as DVB-T-ID, was synthesized using 1,3-indanedione acceptor and dimethoxy vinylbenzene donor units, connected through a thiophene π-spacer. The presence of a dimethoxy vinylbenzene unit and π-spacer in DVB-T-ID significantly improved the absorption behavior by displaying maximum absorbance at ~515 nm, and the reasonable band gap was estimated as ~2.06 eV. The electronic properties revealed that DVB-T-ID SOMs exhibited promising HOMO (−5.32 eV) and LUMO (−3.26 eV). The synthesized DVB-T-ID SOM was utilized as donor material for fabricating solution-processed bulk heterojunction organic solar cells (BHJ-OSCs) and showed a reasonable power conversion efficiency (PCE) of ~3.1% with DVB-T-ID:PC61BM (1:2, w/w) active layer. The outcome of this work clearly reflects that synthesized DVB-T-ID based on 1,3-indanedione units is a promising absorber (donor) material for BHJ-OSCs.

The present work describes the synthesis of a new copper (II) complex with bidentate ligands based on oxindole (indolin-2-one) derivatives, namely: 1H,1′H,1″H-[2,3′:2′,3″-terbenzo[b]pyrrol]-2″(3″H)-one (L1) and [sodium diethyldithiocarbamate (DTC)] (L2) as a second bidentate ligand. The ligand L1 was prepared by the cyclization reaction of oxindole (2-indolone) with phosphorus oxychloride. A mixed-ligand was synthesized using L1 and L2 ligands with copper (Cu (II)) via a simple reflux process. The synthesized mixed Cu (II) complex [C53H44CuN7O4S2 and [Cu(L1)2(L2)]2H2O] exhibited superior solubility in organic solvents like dichloromethane, chloroform, ethanol, methanol, DMF and DMSO. The optical characterizations revealed that the synthesized Cu (II) complex displayed a broad band (2Eg→2T2g) with the absorption at ~420 nm, suggesting a distorted octahedral geometry due to the strong Jahn-Teller distortion of the Cu2+ ion. The elemental analysis confirmed the existence of Cu, C, S, N, and other elements in the synthesized mixed Cu (II) complex. The physicochemical studies of the organic ligand and Cu(II) complex were investigated by TG analysis, NMR, FTIR, SEM, EDX, electronic spectra and cyclic voltammetry measurements. The detection of chloride ions with the prepared mixed Cu(II) complex was studied by cyclic voltammetry measurements at different scan rates.

The fabrication of semiconducting materials with controlled size and morphology is an exciting, rapidly expanding research area for realizing the peculiar physical/chemical properties and the possible practical applications at the nano-to-microscale. Also, the technological applications for nanocomposites of organic/inorganic materials are of great interest in scientific research due to their unique and tunable electronic and optical properties. The semiconducting materials at nanoscale are widely used for the manufacturing of various electronic, electrical and photovoltaic devices owing to their unique band structure, optical properties, good charge mobility and ability to absorb photons from light. Among various photovoltaic devices, a regenerative photoelctrochemical solar cell called DSSC is a promising photovoltaic device for achieving reasonably high conversion efficiency as compared to the conventional silicon solar cells. Various metal oxide semiconducting nanomaterials such as ZnO, TiO2, SnO2, Nb2O5 and CeO2-based thin film electrodes and their nanocomposites have also shown comparably good conversion efficiency of DSSC due to their good optical and electronic properties. These semiconducting metal oxides possess high surface area which is essential for acquiring a high amount of dye adsorption which leads to higher light harvesting efficiency and photocurrent density. Additionally, the morphology and sizes of these semiconducting materials, particularly one dimensional (1D) nanostructures like nanorods (NRs), nanowires (NWs) and nanotubes (NTs)-based electrodes have shown increased electron transfer during the operation of DSSCs. However, there is still a demand for improvements such as the development of a sophisticated potential technology for achieving high photovoltaic properties. On the other hand, the metal oxide and its nanocomposites are also highly capable for the photocatalytic oxidation of organic compounds/ pollutants from waste water. The use of organic dyes, chemicals and heavy metals in many textile and other industries are the major pollutants in water. These harmful organic dyes cause injuries to the ingestion systems, lungs and the respiratory systems of humans. At present, the removal of these dyes from polluted or waste water is an important issue for balancing the ecosystem. Several conventional methods like coagulation, reverse osmosis and adsorbents are extensively employed to remove organic dye from waste water. However, the installations of these methods are highly expensive and also incapable of complete removal of dyes. Recently, the photocatalytic processes have been accepted as promising and effective ways to decompose the organic pollutants into less dangerous matter. Thus, they are considered as efficient and cost-effective alternatives for water remediation. In this chapter, we have briefly discussed the metal oxides like TiO2, and ZnO and their nanocomposites for their potential applications of DSSCs and their photocatalytic degradation. The chapter includes the brief literature surveys, properties and the latest research advancements/trends for the development of various metal oxide nanomaterials, and the nanocomposites of organic/inorganic nanomaterials. The preparation methods, morphologies, and physical and chemical properties of metal oxides have a significant impact on the optical, electrical and electronic properties of the nanomaterials, and on the performance of DSSCs and enhancement of the rate of photocatalytic degradation in dye remediation. [ABSTRACT FROM AUTHOR]

The polyaniline/zinc oxide (PANI/ZnO) nanocomposites were prepared by in situ polymerization of aniline monomer with ZnO nanomaterials and applied as a photocatalyst for the degradation of methylene blue (MB) dye. The morphological observations elicited the agglomerations of PANI sheets which occurred due to the interaction between PANI and ZnO nanomaterials in PANI/ZnO nanocomposites. As compared to pristine PANI, the UV-vis spectra exhibited that the absorption peak of π- π* transitions considerably shifted to higher wavelength at 360 nm from 325 nm in the nanocomposites. The photocatalytic activity results indicated the substantial degradation of MB dye by ~76% over the surface of PANI/ZnO nanocomposite catalyst under light illumination. The PANI/ZnO nanocomposites showed three times higher photocatalytic activity to MB dye degradation compared to pristine PANI might due to high photogenerated electron (ē)-hole (h) pairs charge separation. [ABSTRACT FROM AUTHOR]

Binary dopant mixture of (ZrO2/AgI) (v/v) is prepared in different ratios to enhance the conductivity of the synthesized PANI. DC conductivity of (ZrO2/AgI) (v/v) doped PANI samples is measured in the temperature range (300‐400K). The calculated values of pre‐exponential factor (σ0) indicates that conduction is taking place through hopping process due to localized states present near the Fermi level. Structural changes due to interaction of dopant species with PANI are studied through FT‐IR and Photoluminescence characterization. Photoluminescence (PL) spectra of the doped samples occurred in the form of peaks and the intensities of these peaks vary according to the concentration of dopant mixture. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2682–2687, 2007 [ABSTRACT FROM AUTHOR]