Facile and highly precise pH-value estimation using common pH paper based on machine learning techniques and supported mobile devices

Abstract Numerous scientific, health care, and industrial applications are showing increasing interest in developing optical pH sensors with low-cost, high precision that cover a wide pH range. Although serious efforts, the development of high accuracy and cost-effectiveness, remains challenging. In this perspective, we present the implementation of the machine learning technique on the common pH paper for precise pH-value estimation. Further, we develop a simple, flexible, and free precise mobile application based on a machine learning algorithm to predict the accurate pH value of a solution using an available commercial pH paper. The common light conditions were studied under different light intensities of 350, 200, and 20 Lux. The models were trained using 2689 experimental values without a special instrument control. The pH range of 1: 14 is covered by an interval of ~ 0.1 pH value. The results show a significant relationship between pH values and both the red color and green color, in contrast to the poor correlation by the blue color. The K Neighbors Regressor model improves linearity and shows a significant coefficient of determination of 0.995 combined with the lowest errors. The free, publicly accessible online and mobile application was developed and enables the highly precise estimation of the pH value as a function of the RGB color code of typical pH paper. Our findings could replace higher expensive pH instruments using handheld pH detection, and an intelligent smartphone system for everyone, even the chef in the kitchen, without the need for additional costly and time-consuming experimental work

Optical Band Gap Tuning, DFT Understandings, and Photocatalysis Performance of ZnO Nanoparticle-Doped Fe Compounds

Iron-doped Zinc oxide nanoparticles were produced by the sol-gel combustion method. This study aims to see how iron doping affects the structural, optical, and photocatalytic characteristics of ZnO composites. XRD examined all samples to detect the structural properties and proved that all active materials are a single hexagonal phase. The morphology and particle size were investigated by TEM. Computational Density functional theory (DFT) calculation of the band structure, density of state, and charge distributions for ZnO were investigated in comparison with ZnO dope iron. We reported the application results of ZnO doped Fe for Methylene blue dye removal under photocatalytic degradation effect. The iron concentrations affect the active material’s band gap, producing higher photocatalytic performance. The acquired results could be employed to enhance the photocatalytic properties of ZnO

Synthesis of novel semi-squaraine derivatives and application in efficient dye-sensitized solar cells

A series of novel semi-squaraine sensitizers with various architectures and anchors have been synthesized and utilized in dye-sensitized solar cells. These dyes combine indole- or carboline-based electron rich units with strongly electron-withdrawing cyanoacetate moieties or other functional anchoring moieties. They were thoroughly characterized as per their structural, optical and electrochemical properties and the behavior of the as-prepared solar cells were examined in detail using linear sweep voltammetry, electrochemical impedance spectroscopy and DFT calculations. Amongst the herein reported dyes, AKSq1, incorporating a free hydroxyl group directly attached to the squarate ring, exerts the optimum performance in dye-sensitized solar cells, despite the fact that this dye presents the lowest extinction coefficient among the molecules under study. AKSq1 demonstrates power conversion efficiency of 2.63%, about 14% higher than the efficiency obtained with the corresponding reference dye, the commercially available, high-performance, metal-free dye D35, under the same cell fabrication and measuring conditions. This result is attributed to the presence of free squaryl hydroxyl moiety ensuring efficient dye chemisorption and the existence of a lipophilic dodecyl group preventing the aggregation of the squaraine sensitizer onto the semiconductor's surface either by itself, or via increased intercalation of the C12 chain with the chenodeoxycholic acid coadsorbent. © 2019 Elsevier Lt