Natural Dyes: From Cotton Fabrics to Solar Cells

This article will discuss natural dyes’ role, from colouring the cotton fabrics with some functionality to harvesting sunlight in the dye-sensitized solar cells. Natural dye colourants are identical to the low light- and wash-fastness. Therefore, an approach to improving the colourant’s physical properties is necessary. Colouring steps employing silica nanosol and chitosan will be presented. The first part will be these multifunctional natural dye coatings on cotton fabrics. Then, functionality such as hydrophobic surfaces natural dyed cotton fabrics will be discussed. Natural dyes are also potential for electronic application, such as solar cells. So, the second part will present natural dyes as the photosensitizers for solar cells. The dyes are adsorbed on a semiconductor oxide surface, such as TiO2 as the photoanode. Electrochemical study to explore natural dyes’ potential as sensitizer will be discussed, for example, natural dyes for Batik. Ideas in improving solar cell efficiency will be discussed by altering the photoanode’s morphology. The ideas to couple the natural dyes with an organic–inorganic hybrid of perovskite and carbon dots are then envisaged

Synthesis of Nanocomposites Reduced Graphene Oxide-Silver Nanoparticles Prepared by Hydrothermal Technique Using Sodium Borohydride as A Reductor for Photocatalytic Degradation of Pb Ions in Aqueous Solution

Heavy metals are pollutants that are harmful to living things and the environment can be degraded by microbes or understood by other living things so that they can cause health problems. One of the heavy metals that is often found in wastewater is lead. Lead is widely used in the manufacture of batteries, metal products such as ammunition, cable coatings, Polyvinyl Chloride (PVC) tubing, solder, chemicals and dyes This use causes humans to be exposed to large amounts of lead. One method to deal with lead pollution is to use photocatalysts. Photocatalysts react with heavy metals and reduce them so that the level of toxicity becomes lower than before through photocatalytic reactions. In this study, synthesis of reduced graphene oxide/silver nanoparticle nanoparticles was performed by facile hydrothermal methods for photocatalytic degradation of Pb ion. The characterization results indicate that the synthesis has been successfully carried out. The successful result of rGO/AgNPs nanocomposites synthesis was proved by several techniques such as X-ray diffraction analysis, Raman, UV-Vis spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray analysis (EDX). This indicates the presence of these groups in the graphene oxide and rGO/AgNPs samples, respectively. The resulting rGO/AgNPs nanocomposite has an absorbance peak at a wavelength of 267 nm. The diffraction peaks for nanocomposites rGO/AgNPs and their Miller indices were 38.08° (111), 44.16° (200), 64.44° (220), and 77.44° (311). The Raman spectra of rGO/AgNPs exhibits D bands at 1334,13 with intensity of 630,60 cm−1 and G band at 1594,61 with intensity of 477,29 cm−1. The ID/IG ratio rGO/AgNPs-NaBH4 is ~1,32. Furthermore, the photocatalytic activity test results showed that the rGO/AgNPs nanocomposite was able to reduce Pb2+ to Pb with a maximum exposure time of 1.5 hour