Uahengo, VeikkoEnkali, Ndapewa Linda2026-03-252026-03-252025http://hdl.handle.net/11070/4240A thesis submitted in fulfilment of the requirements for the degree of masters of science in ChemistryZinc Sulphide (ZnS) is one of the wide band gap (Wurtzile; 3.91eV and Spalerite; 3.54eV) semiconductors suitable for application in dye-sensitized solar cell (DSSCs). However, ZnS absorb UV light which only contribute about 5% total energy of solar radiation. By sensitizing ZnS photo anode with dye sensitizer in DSSC, light absorption is extended to visible regions (which contribute 43% total energy) of solar radiation spectrum. Despite this, discovering the best photo anode materials (sensitizer and semiconductor) remains a challenge in DSSCs. In this work, an experimental study on the photosensitization of ZnS nanoparticles with five different metal-free dyes was carried out. The ZnS nanoparticles and five different Thiazole and Isatin based metal-free dyes were synthesized and characterized. Grafted ZnS-dye samples were fabricated and characterized and the effect of solvatochromism on dyes on ZnS were investigated. All data were collected from X-ray diffractometer (XRD), Proton Nuclear Magnetic Resonance (1HNMR), Fourier Transform Infrared (FTIR) spectroscopy and analyzed Ultraviolet and Visible light (UV-vis) spectroscopy. XRD confirms that the crystal structure of the ZnS nanoparticles and the chemical structures of dyes and their vibration frequencies were confirmed by 1HNMR and FTIR, respectively. Among the five dyes, Dye1, Dye2 and Dye5 showed best photo response before and after grafted on ZnS nanoparticles. Broad peaks and high absorption intensities were observed on these dyes. Little or no absorption were observed for Dye3 and Dye4 before and after grafted on ZnS nanoparticlesenPhotosensitizationNanoparticlesSolvatochromismGraftingCharacterizationMetal-free dyesNamibiaUniversity of NamibiaThesis