2020-01-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/707115Abstract: The goal of this project is to search for key factors to increase the long-term stability of organic solar cells, which is currently the main challenge for their widespread adoption in everyday practice. Highly effective photovoltaic material should have the following characteristics: narrow band gap, low HOMO orbital, high hole mobility, optimal morphology and long-time thermal stability. Because of the lack of fundamental understanding of the phase behavior of donor-acceptor mixtures in the active layers of organic photovoltaic cells, we propose to carry out a systematic study of the structural changes that occur after the phase separation of different systems based on a mixture of conjugated polymers with fullerenes as well as with other (non-fullerene) acceptors. The studied structures will be checked for the energy conversion efficiency, and special attention will be paid to increasing the long-term stability of the characteristics of the photoactive layers of organic solar cells. The specificity of the production of polymer photovoltaic cells leads to the fact that the photoactive layer is formed as a thermodynamically unstable system (with a kinetically frozen state). Therefore, our project aims to study the evolution of such states and to find a way to stabilize them in the production of the material. This is a new task that has not been solved before. Its implementation within the framework of computer modeling will provide a unique opportunity to directly observe the processes occurring in the photoactive polymer layer at the molecular level from its formation to destruction. Thus, the formulated problems of the project and the expected results are completely new and reflect the modern challenges in organic solar cells. The achievement of the project goals will allow to obtain thermally stable polymer photovoltaic materials of a new generation, as well as gain the fundamental knowledge about the influence of the chemical structure of conjugated polymers on the stability of morphologies of composites based on them.