Expression of Concern: Solid-state dye-sensitized solar cells based on Zn1-xSnxO nanocomposite photoanodes.

Expression of Concern for 'Solid-state dye-sensitized solar cells based on Zn1-xSnxO nanocomposite photoanodes' by Ayat Nasr El-Shazly et al., RSC Adv., 2018,8, 24059-24067, DOI: https://doi.org/10.1039/c8ra02852d.

Solid-state dye-sensitized solar cells based on Zn1-x Sn x O nanocomposite photoanodes.

Solid-state dye-sensitized solar cells (ss-DSSCs) comprising Sn2+-substituted ZnO nanopowder were purposefully tailored via a co-precipitation method. The solar cells assembled in this work were sensitized with N719 ruthenium dye and insinuated with spiro-OMeTAD as a solid hole transport layer (HTL). Evidently, significant enhancement in cell efficiency was accomplished with Sn2+ ions-substituted ZnO photoelectrodes by maintaining the weight ratio of SnO at 5%. The overall power conversion efficiency was improved from 3.0% for the cell with pure ZnO to 4.3% for the cell with 5% SnO substitution. The improvement in the cell efficiency with Sn2+-substituted ZnO photoelectrodes is attributed to the considerably large surface area of the nanopowders for dye adsorption, efficient charge separation and the suppression of charge recombination provided by SnO. Furthermore, the energy distinction between the conduction band edges of SnO and ZnO implied a type II band alignment. Moreover, the durability as well as the stability of 15 assembled cells were studied to show the outstanding long-term stability of the devices made of Sn2+ ion substituted ZnO, and the PCE of each cell remained stable and ∼96% of its primary value was retained for up to 100 h. Subsequently, the efficacy was drastically reduced to ∼35% after 250 h of storage.

Fluorescence sensing of dichlorvos pesticide by the luminescent Tb(III)-3-ally-salicylohydrazide probe.

A fluorescent probe was developed and characterized, it consisted of terbium(III) with 3-ally-salicylohydrazide in ethanol, in which the 1:2 [Tb3+ :S1 ] molar ratio was the best stoichiometric ratio for the probe. The ligand 3-ally-salicylohydrazide (S1 ) was synthesized, then was confirmed by IR, CHN, LC-MS and 1 H NMR. The sensitivity of the probe's fluorescence spectra towards the presence of eight organophosphorus pesticides in ethanolic solution was studied, in which the probe showed marked sensitivity towards dichlorvos pesticide. A tangible enhancement of the probe's fluorescence intensity was observed as a consequence of the gradual addition of dichlorvos pesticide. The calculated limit of detection (LOD) was 1.183 µM and limit of quantitation (LOQ) was 3.94 µM. Further characterization of the nature of forces acting in the interaction of the probe with dichlorvos was performed by calculation of binding constants at different temperatures according to the Benesi - Hildebrand equation, and the thermodynamic parameters ΔH, ΔS and ΔG. In order to assess the analytical applicability of the method, the influence of various potentially interfering anion and cations that naturally occur in water and soil were calculated.