Just Accepted
Shaonan Liu, Shuixing Dai*, Minghua Huang
https://doi.org/10.1016/j.cjsc.2024.100277
ABSTRACT
Recently, 1,8-naphthalimide (NI) molecules have emerged as a
new category of organic electron transport materials (ETMs) employed in organic
solar cells (OSCs). Among them, NI molecules with a "NI-π-NI"
molecular structure commonly exhibit over aggregation in films owing to their
planar molecular structures, which is unfavorable for solution-processed film
fabrication in OSC devices. In this work, we successfully synthesized a new NI
molecule named NDT-2, employing a strategy that incorporates a solubilizing
ester group modification to induce twisted molecular planarity, thereby
reducing intermolecular over-aggregation and optimizing quality of the film.
Interestingly, the NDT-2 modified by ester groups as a π bridge exhibits an
enlarged molecular dihedral angle, enhanced alcohol solubility, a smoother film
surface morphology, and improved film forming quality. Ultimately, OSCs
incorporating NDT-2 as the ETM achieved a notable power conversion efficiency
(PCE) of 17.1%. This study introduces a design strategy that utilizes ester
functional groups to improve film forming quality of ETM, offering valuable
insights for the development of advanced, alcohol-soluble NI molecules as efficient ETMs in OSCs.