SPERAPHOUS · SPEctrally Resolved Action PHOtocurrent Ultrafast Spectroscopy

With the rise in global warming, transitioning to renewable energy is more necessary than ever. Organic solar cells (OSC), with their flexibility and lower production costs and footprint, offer promising platforms for efficient light harvesting and net zero greenhouse gas emission. While OSCs nowadays depict 20% power conversion efficiencies, their performance is hindered by the bound states leading to photocurrent losses as they cannot provide free charge carriers. Efforts have been made to understand these bound states such as bound excitons, bound charge transfer states, and localized polarons as mitigating them could boost efficiency. However, identifying and analysing their dynamics requires extensive experimental work involving various techniques, mathematical tools, and modelling, further complicated by linking experimental results to device performance. Herein, by combining my expertise in photocurrent spectroscopy on optoelectronic devices under operando conditions with the host’s expertise in ultrafast multidimensional spectroscopy, I propose the SPEctrally Resolved Action PHOtocurrent Ultrafast Spectroscopy (SPERAPHOUS). This will spectro-temporally characterize bound states in OSCs under operando conditions ultimately leading to the development of design rules to improve OSCs efficiency. To achieve this, an interferometric system combined with ultrafast pulses, providing the spectro-temporal information, will be applied on Non-Fullerene Acceptor (NFA): Donor OSCs whose photocurrent response will be measured. SPERAPHOUS will contribute to the OSC research community and pave the way for investigating other optoelectronic devices, such as those based on perovskites and two-dimensional materials. Furthermore, through SPERAPHOUS, I will gain new knowledge and skills in ultrafast multidimensional spectroscopy, and I will enhance my academic skills broadening my scientific background leading to research independence.