Diseño e implementación de una celda orgánica fotovoltaica semi-transparente

Organic polymeric solar cells require thin absorber layers due to intrinsic low exciton diffusion distances, thus showing low absorption of light. They are also characterized by having a low absorption peak, whose position lies in the near-infrared, slightly affecting the visible spectrum. By depositing thin silver layers of 10 nm for the back electrode, a semi-transparent organic solar cell can be created. Attractive outcomes could result from these devices, like solar cell windows that would remain visually transparent, while still collecting energy from the sun, or tandem polymeric solar cells. The formation of a non-homogeneous and discontinuous silver layer when depositing an ultra-thin film turns into a high resistivity electrode, therefore limiting the area that such devices can reach and the maximum power that the cell can offer. The goal of this bachelor thesis was to up-scale semi-transparent organic solar cells by characterizing the thin electrode conductivity and enhancing its charge collection using thick grid-like layers of silver. The cause for such high resistivity was confirmed by finding silver agglomerations of 30 nm in size, and a lower limit for its value was found by studying the silver bulk resistivity. The upscaling losses were determined in terms of the increase in area, and charge-collecting grids were consequently tested. The building of organic solar cells by spin-coating and vapour depositions was proved functional on top of non-flat substrates with roughness of the order of 100 nm. Fill Factor enhancements were found by designing optimal grid structures compatible with highly transparent cells