Quasi-Steady-State Measurement of Exciton Diffusion Lengths in Organic Semiconductors

Understanding the role that exciton diffusion plays in organic solar cells is a crucial to understanding recent rise power conversion effciencies brought about by non-fullerene acceptors (NFA). Established methods for measuring lengths require specialized equipment designed high-resolution time-resolved photoluminescence (TRPL). Here we introduce technique, coined pulsed-PLQY, measure length of without any temporal measurements. Using Monte-Carlo model simulate dynamics within thin film semiconductor and analyse results using both pulsed-PLQY TRPL methods. We find has larger operational region depends less on excitation fuence than approach. validate these simulated preforming measurements films reproduce predicted trends. Pulsed-PLQY then used evaluate variety technologically relevant semiconductors. It found NFA's are much benchmark fullerene this increase driven an diffusivity.