As a young research scientist, I have dedicated my research efforts on the highly dynamic and ever-evolving field of organic solar cells (OSCs). My Ph.D project aims at investigating the impact of thermal stress on the morphology and ultrafast charge carrier dynamics within a series of terpolymers, designed for OSC applications. To achieve this, I employ cutting-edge ultrafast femtosecond transient absorption (fs-TA) spectroscopy alongside morphological characterization techniques to unveil crucial insights into the efficiency and viability of OSCs, which hold great potential for sustainable energy solutions. My research therefore seeks to unravel the ultrafast charge carrier dynamics and underlying molecular mechanisms governing these prospective OSC active layers.