Investigating Underlying Mechanisms for Nonfullerene Hybrid Bulk Heterojunctions‐Based Organic Magnetoresistance

Abstract

Abstract Nonfullerene acceptors (NFAs) are potential candidates for high‐performance organic solar cells. As a group of promising organic optoelectronic materials, it is of particular importance to further explore while establishing their novel functionalities for other critical applications such as low power consumptions and high‐speed organic spintronic devices for data storage and memories. Here, a joint of experimental and theoretical studies are performed for the magneto‐transport in PM6:Y6 and PBDB‐T: ITIC‐based prototypical nonfullerene hybrid bulk heterojunction (BHJ) systems. Robust magnetic‐driven behaviors can be realized due to the existence of charge transfer states (CTS) for the systems. Largely stable high and low resistive states can be well achieved through a wide temperature range from 300 K to 4 K. Magneto‐responses are dealt with at different field strengths separately based on microscopically theoretical models. The interior spin dynamics lay primarily on field‐induced coherent spin mixing mechanisms. The main channels for pronounced OMR effects with negative signs stem from the triplet exciton‐polaron interaction and coulomb blockade hopping transport upon charge injection. More importantly, the polaron back transfer (PBT) turns out to be desirable for nonfullerene molecular spintronics. This study opens a new avenue for novel applications of NFAs in organic spintronics.

Keywords

• charge transfer states
• nonfullerene acceptors
• organic bulk heterojunctions
• organic magnetoresistance
• organic spintronics