ABSTRACT
In this study, a semiconductor-doped nanocomposite material (Zn-doped Er2O3 nano-composites) was prepared via a single-step wet-chemical technique at alkaline pH. Fourier-transform infrared spectroscopy (FT-IR), UV/Vis spectroscopy, photoluminescence spectroscopy (PL), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (XEDS), and X-ray powder diffractometry (XRD) were applied to determine the structural and morphological properties of the Zn-doped Er2O3 nanocomposite. A thin layer of aggregated Zn-doped Er2O3 nanocomposite was fabricated on the flat surface of a glassy carbon electrode (GCE) with 5% ethanolic Nafion as conducting coating binder for the development of a selective and sensitive p-nitrophenol (para-NP) capturing electrochemical probe for environmental remediation. After the fabrication of the sensor, a novel current-potential (I-V) electrochemical approach was applied to determine its selectivity and sensitivity together with all the necessary analytical parameters against para-NP. Moreover, the calibration plot was found to be linear with the linear dynamic range (LDR) of para-NP concentration. The limit of detection (LOD) at a signal-to-noise ratio of 3 (S/N â¼ 3) and sensitivity were also calculated to be 0.033 ± 0.002 pM and 28.481 × 10-2 µA µM-1 cm-2, respectively, based on the gradient of the calibration plot, and the limit of quantification (LOQ) was determined to be 0.11 ± 0.02 pM. This work demonstrates a well-known approach for the first time that can be used for the development of efficient electrochemical sensors. These sensors based on semiconductor doped nanomaterials embedded onto the GCE for the detection of toxic chemicals in an aqueous system as an environmental remediation. It can be further applied for the analysis of real environmental samples and in the healthcare field.
ABSTRACT
In the present work, the absorption, emission spectra and dipole moments(µ(g), µ(e)) of N, N-bis (2, 5-di-tert-butylphenyl)-3, 4:9, 10- perylenebis (dicarboximide) (DBPI) have been studied in solvents of various polarities at room temperature. Using the methods of solvatochromism, the difference between the first excited singlet state (µ(e)) and ground state (µ(g)) dipole moments was estimated from Lippert - Mataga,, Bakhshiev, Kawski - Chamma - Viallet equations. The change in dipole moment (Δµ) was also calculated using the variation of the Stokes shift with microscopic solvent polarity parameter (E(T)(N)). It was observed that the value of excited singlet state dipole moment is higher (3.53 Debye) than the ground state one (1.92Debye), showing that the excited state of DBPI is more polar than the ground state.
