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Introduction: With increasing prevalence of dental erosion, this study explores the protective role of traditional fluoride-based products and newer formulations on eroded enamel. Aims: To assess the protective effectiveness of casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) and sodium fluoride (NaF) on human enamel against erosion using surface microhardness (SMH) and Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses. Materials and Methods: Ten extracted human third molars were sectioned to obtain 40 enamel sections and randomly assigned into four groups (n = 10) and treated as follows: G1 (Sound Enamel), G2 (Erosive Challenge), G3 (CPP-ACPF + Erosive Challenge), and G4 (NaF + Erosive Challenge). All samples were subjected to Vicker's SMH analysis, while changes in surface morphology and elemental composition were validated in few representative samples using FTIR and SEM, respectively. Statistical Analysis: Paired samples test, Kruskal-Wallis test, and Tukey HSD test were performed using SPSS software version 23 setting P value < 0.05 as statistically significant. Results: The mean SMH1 values for the experimental groups G3 and G4 were significantly higher (426.58VHN and 455.83VHN) when compared to G1 (P = 0.000) and G2 (P = 0.000). In SEM analysis, G2 showed eroded honeycomb appearance compared to the smooth homogenous surface of G1, while both G3 and G4 showed deposition of some precipitates. FTIR analysis revealed that in G3 and G4, a characteristic peak of phosphate vibrations between 528 and 823 cm-1 and carbonate bands at 845-932 cm-1 was observed. Conclusions: Both CPP-ACPF and NaF demonstrated a protective effect on enamel against erosive challenge by an orange juice-based beverage. [ABSTRACT FROM AUTHOR]

Here, we synthesized metal-free organic dye (CCPICPB) with two carbazole donor groups and two anchoring groups that exhibit a panchromatic absorption in the near-infrared range of up to 750 nm. To study the photophysical properties of synthesized CCPICPB dye, the UV–Vis and cyclic voltammetric experiments were studied and the obtained results were validated with theoretical simulation studies. After that, the solvothermal approach is used to synthesize pristine anatase and calcium (Ca)-doped TiO2 microspheres with a smooth morphology. These microstructures are examined in depth using XRD, electron microscopy and electrochemical analysis methods. On TiO2 and Ca-doped TiO2 photoanode materials, we first evaluated the performance of CCPICPB dye. Upon our optimized experimental condition, the 3% Ca-TiO2 photoanode-based device exhibits an efficiency of 4.04%, which is greater than that of the pristine TiO2 photoanode-based device (2.93%). Because of the quicker electron transport in the Ca-TiO2 film, the short-circuit current density and efficiency of DSSCs were improved. Moreover, when the CCPICPB dye was used as a co-sensitizer with the common Ru(II) dye (Z907), interestingly it showed the highest efficiency (6.11%) when compared with Z907 alone (5.12%). This improved efficiency of the co-sensitized device resulted from greater VOC conjugated with improved JSC. The JSC was improved because CCPICB dye could compensate for the photocurrent loss caused by redox electrolyte while the VOC was improved because electron recombination was inhibited under the co-sensitization conditions. [ABSTRACT FROM AUTHOR]

We synthesized POBA dye and studied its performance as a sensitizer and co-sensitizer. In addition, we present a simple method for producing Ni-doped TiO2 with various molar concentrations for use as a photoanode in a DSSC. Further, poly(vinylidene fluoride)/polyethylene glycol (PVDF-PEG) gel polymer electrolytes (GPEs) having different concentrations of 1-n-hexyl-3-methylimidazolium iodide were prepared and optimized for usage in DSSCs. We initially tested the performance of POBA dye on TiO2 and Ni-doped TiO2 photoanode materials. Among the POBA sensitized devices, 4% Ni–TiO2 showed a high efficiency of 1.85%. Then, we sensitized Z907 dye on the 4% Ni–TiO2 photoanode, followed by sensitizing it with POBA, which compensated the absorption defect of the Z907 dye as well as filling the gap between the standard dye molecules. This approach enhances and broadens the absorption spectrum of the dyes by molecular filling, compensates for the lack of absorption of Z907, and reduces the recombination of charges. The Z907-based DSSC showed 4.52% efficiency, and after co-sensitization, the DSSC showed an increase in efficiency (5.77%). These findings show that co-sensitizers can cover the naked spectrum in the ultraviolet-visible region, fill the empty space on Ni–TiO2, and reduce recombination reactions. The main motive of this research is to enhance the photo-ability of sensitizers and metal-free co-sensitizers in a Ni–TiO2 photoanode and blend gel polymer electrolyte-based DSSCs. [ABSTRACT FROM AUTHOR]

ZnO/rGO composites are prepared by the conventional solid-state reaction method. Structural properties of prepared compounds were studied using XRD technique and it is observed that all the samples are crystallized in wurtzite structure. Electrical resistivity measurements were carried out using four probe method employing a closed cycle refrigerator. With addition of rGO, colossal reduction in the resistivity is observed which is about three orders of magnitude smaller than that of the pure sample of ZnO. Room temperature Hall measurements were performed to estimate the bulk concentration and results show that addition of rGO into ZnO matrix enhances the number of charge carriers. Thermopower measurements were carried out using differential dc method and a large reduction in Seebeck coefficient is observed. [ABSTRACT FROM AUTHOR]