OPTICAL AND PHOTOVOLTAIC PROPERTIES OF ORGANIC SOLAR CELLS VS BULK-HETEROJUNCTION MORPHOLOGY

Abstract

The performance of organic bulk-heterojunction solar cells is closely tied to the morphology of their active layer, a disordered mixture of organic donor and acceptor materials, where photoexcitation and charge generation occur. In this thesis work, optical mixing principles are utilized to model the common active layer structure PM6:Y6. By controllably varying the size and shape of acceptor inclusions within a donor matrix, I investigate how changes in morphology affect the optical properties of the resulting effective medium. This finding is further utilized in transfer matrix optical simulations in combination with the Hecht equation to analyze the effect of morphology on the photovoltaic properties of organic solar cells. The reported findings can guide the optimal fabrication of similar structures by providing valuable insights into which characteristics of the blend could potentially hinder or benefit the performance of photovoltaics.