Jamming Giant Molecules at Interface in Organic Photovoltaics to Improve Performance and Stability.

A novel approach for depositing the giant molecule acceptor (GMA) at the donor-acceptor interface to enhance the efficiency and stability of organic photovoltaic (OPV) devices through a designed interface-enhanced layer-by-layer device fabrication protocol is proposed. The giant molecule acceptor DQx-Ph is mixed with the polymer donor in the bottom layer to form a polymer donor fibril phase and a mixed phase, followed by subsequent deposition of the main acceptor L8-BO. The L8-BO solution swells the bottom layer and alters the localized morphology of the mixing phase, introducing L8-BO fibrillar crystallization and pushing DQx-Ph giant molecules outwards to the fibril interfaces. Through this approach, the localized morphology and optoelectronic property of the bulk heterojunction are optimized. This configuration maintains the superior transport properties of L8-BO while integrating the high open-circuit voltage characteristics of DQx-Ph. Additionally, exciton dissociation and charge generation are simultaneously enhanced, with suppressed energy losses. A power conversion efficiency of 19.9% with improved operational stability is achieved, underscoring the importance of GMA interface jamming in advancing OPV technology. This study provides new insights into the development of ancillary OPV materials to overcome the critical limitations in OPV, revealing innovative approaches for photovoltaic technologies.