Revealing the influence of the dispersion property of charge transport on the stability of organic solar cells

Charge transport is an important property that influences the stability of organic solar cells (OSCs). While decreased average charge mobility during degradation is recognized as an essential factor reducing device stability, the dispersion property of charge transport is often overlooked. The dispersion parameter characterizes the dispersion of transit times in charge transport. A high dispersion parameter typically indicates a significant population of slow charge carriers in OSCs, which could introduce more charge recombination and ultimately compromise device stability. In this work, we demonstrate that the combined effect of dispersion parameter and charge mobility serves as a key indicator of degradation pathways, underscoring the critical role of the initial morphology of the active layer in device stability. This work not only establishes a morphology-transport stability framework for enhancing the charge transport stability but also discovers the significance of sustaining a balanced mobility-dispersion property for ensuring the long-term stability of OSCs.