Yohannes, Teketel (Professor)Yirga, Getachew2018-07-122023-11-182018-07-122023-11-182012-06http://etd.aau.edu.et/handle/12345678/8377This thesis focused on the study of dye-sensitized solar cells (DSSCs) based on ZnO nanoparticle. Our work started by synthesizing ZnO nanopartcile using sol-gel method. ZnO nanoparticles were synthesized and the size of the nanoparticle (1.14 nm) was determined by using effective mass approximation model. Natural sensitizers extracted from Jacaranda mimosifolia, Bougainvillea spectabilis, Carissa ovata, Amarathus iresine, Beta vulgaris, and Hibiscus sabdariffa used for sensitizing ZnO nanoparticle. All natural sensitizers were extracted by water and ethanol, absorption spectra were measured and all natural sensitizers absorbs in the visible region. Devices were fabricated using ZnO nanoparticles and with all the above natural sensitizers, then the photoelectrochemical performance were measured. DSSCs based on ZnO nanoparticles and ethanol extract of Amarathus iresine sensitizers have shown relatively good conversion efficiency of 0.039. The incident photon to current conversion efficiency (IPCE), short circuit current density (Jsc) and Voc were measured for all the above sensitizers. Also comparative study were made using TiO2 nanoparticle based DSSCs sensitized by Bougainvillea Spectabilis, Carissa ovata, and Jacaranda mimosifolia with ZnO based DSSCs sensitized by the same sensitizers. In TiO2 nanopartcile based DSSCs the photoelectrochemical (PEC) performance we found relatively higher than the ZnO nanopartcles based DSSCs as expected. The data we got from TiO2 and ZnO based DSSCs was analyzed and finally some of the problem that limit the conversion efficiency were discussed.enZnO NanoparticlesThesis