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This work reports the influence of atomic layer deposition (ALD) using its variants as thermal ALD, remote plasma ALD (RPALD), and direct plasma ALD on the physical parameters of the as-deposited SnO x films. The deposition process and chemical composition are related to their electronic band structure such as valence band maximum, conduction band minimum, band gap, and work function. Oxidant agents such as H 2 O, O 2 , and O 3 were evaluated with deposition temperatures of 80 and 200 °C. Each of the SnO x films were integrated into a solar cell prototype as an electron transport layer, yielding the maximum photovoltaic efficiency of 15.15% for the cell using the SnO x film obtained with oxygen-assisted RPALD at 80 °C. Tin oxides deposited at 200 °C using ozone and oxygen, respectively, feature surface plasmon resonance (SPR) under near-infrared irradiation (0.5 eV), which was detected by reflection electron energy loss and X-ray photoelectron spectroscopies. The unintentionally incorporated substitutional hydrogen acting as a shallow donor is responsible for the SPR effect, defect states in the band gap, and considerably reducing photovoltaic efficiency of the solar cells studied. This doping can be detected by in situ quadrupole mass spectroscopy characterization in the absence of CH 2 among reaction byproducts at the ALD oxidation step.

Heavy metals in water are a serious environmental problem due to their accumulation and toxicity; there are several processes we can use to address this issue, but adsorption is the most popular due to its simplicity and efficiency. Polysaccharides such as cellulose have received attention as adsorbents for heavy metals, and cotton–chitosan composites (CCs) were developed here with nontoxic reagents such as carboxylic acids as crosslinkers and NaH2PO4 as a catalyst to achieve chitosan covalent crosslinkage into oxidized cotton textiles with H2O2. The composites were characterized by fourier-transform infrared spectroscopy (FTIR), elemental analysis (EA), X-ray photoelectron spectroscopy (XPS), atomic-force and scanning electron microscopy (AFM and SEM), and tensile strength; the adsorption of lead ions (Pb) was evaluated with cotton–chitosan composites and quantified by microwave plasma atomic emission spectroscopy (MP-AES). The composites showed a maximum incorporation of chitosan of 27.62 mg per gram of cotton textile. A tensile strength analysis of the composite showed a Young’s modulus approximately 1 MPa higher than that of cotton textile. The adsorption of lead ions with composites in an aqueous solution at pH 5 and 25 °C was circa 74% after 6 h of contact, as determined by MP-AES. This work is an approach to demonstrate the potential of these polysaccharides, modified by “green” procedures to remove pollutants from water.

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In this study, chitosan was chemically modified with 2-methylpyridine. Subsequently, the modified chitosan was cross-linked to cellulose using succinic anhydride. Additionally, the capacity of cellulose derivatives to adsorb Pb(II) ions in an aqueous solution was studied through the determination of Pb(II) ions concentration in water, using microwave plasma atomic emission spectroscopy (MP-AES). A maximum adsorption capacity of 6.62, 43.14, 60.6, and 80.26 mg/g was found for cellulose, cellulose-succinic acid, cellulose-chitosan, and cellulose-chitosan-pyridine, respectively. The kinetic data analysis of the adsorption process showed a pseudo-second-order behavior. The increase in metal removal from water is possibly due to metal chelation with the carbonyl group of succinic acid, and the pyridine groups incorporated into chitosan.