Plasmon metal nano-particles as a mechanism to suppress charge recombination and enhance photons capture in thin film polymer solar cell.

Abstract

By enhancing the key processes of light absorption, charge transport, and device stability, the thesis contributes to developing sustainable, high-efficiency energy solutions. Moreover, this thesis highlights incorporation of plasmonic nanoparticles (NPs) into the active layers of organic thin film solar cells to enhance their performance. Especially, the study focuses on the addition of the plasmonic silver magnesium (Ag/Mg) NPs, and nickel-silver (Ni/Ag) nanoclusters into the active layer of Poly(3- hexylthiophene-2,5-diyl)(P3HT):[6,6] phenyl-C61-butyric acid methyl ester (PC61BM) polymer blend. Furthermore, we hvae investigated the incorporation of cobalt sulfide (CoS) NPs into the Poly [[4,8- bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4- b]thiophenediyl ]] (PTB7):[6,6]-Phenyl-C71-butyric acid methyl ester (PC71BM) active layer. The introduction of plasmonic NPs is aimed at improving light absorption, charge carrier generation, charge recombination, and overall efficiency of thin film polymer solar cells. The occurrence of localized surface plasmonic resonance (LSPR) due to the inclusion of plasmon NPs in photo-active layer positively influenced the optical and electrical properties of the medium that leads to improved light harvesting. Through a series of experimental studies, the thesis demonstrates that the inclusion of Ag/Mg, and Ni/Ag NPs in P3HT:PC61BM leads to significant improvements in device performance. Each NPs system is characterized in terms of its synthesis, incorporation methods, and the resulting morphological and optoelectronic properties of the active layer. Moreover, the incorporation of CoS NPs into the PTB7:PC71BM blend is investigated, highlighting the positive effects of combining these materials. The results demonstrated an enhancement in both the absorption spectrum and the charge transport properties, contributing to an overall increase in device performance as the power conversion efficiency (PCE) of the optimized device was improved by 37% compared to the reference solar cell device. The research outcomes contribute to the understanding of plasmonic-enhanced organic thin film solar cells and offer new possibilities for the material combinations and mechanisms that influence performance improvements. The results presented in this thesis are supported by three peer-reviewed publications. Which details the experimental approaches, analyses, and conclusions drawn from the study. Generally, this work demonstrates the potential of plasmonic NPs and quantum confinement effect to advance the efficiency and viability of organic thin film technologies, paving the way for future developments in sustainable energy solutions.