@article {28556,
	title = {Tweaking the Molecular Geometry of a Tetraperylenediimide Acceptor},
	journal = {ACS Appl. Mater. Interfaces},
	volume = {11},
	number = {7},
	year = {2019},
	month = {2019 FEB 20},
	pages = {6970-6977},
	type = {Article},
	abstract = {Partial flattening of the spatially extended molecular scaffold has been employed as an effective tactic to improve the device performance of a perylenediimide (PDI)-based small-molecule acceptor because the less twisted yet not completely planar molecular geometry is anticipated to improve the molecular packing and thereby attain a more suitable balance between the carrier transport ability and phase domain size. A small-molecule acceptor BF-PDI comprising four alpha-substituted PDI units attached around a 9,9{\textquoteright}-bifluorenylidene (BF) central moiety is designed and studied in polymer solar cells. The BF group is deemed a ring-fused analogue of the tetraphenylethylene (TPE) unit. Due to the less twisted and better conjugated BF skeleton, BF-PDI displays more delocalized lowest unoccupied molecular orbital. By virtue of both the electronic and steric effects, BF-PDI is suggested to bring about superior intermolecular stacking and donor-acceptor phase separation morphology in blend films. Indeed, the experimental results show that BF-PDI displays improved charge transport ability and a higher power-conversion efficiency of 8.05\% than that of TPE-PDI. Grazing-incidence wide-angle X-ray diffraction and resonant soft X-ray scattering confirm the more compact and ordered molecular packing as well as smaller domain sizes in the P3TEA/BF-PDI blend.},
	isbn = {1944-82441944-8252},
	url = {https://pubs.acs.org/doi/10.1021/acsami.8b19065},
	author = {Han, Han<sup>{\textdagger}</sup> and Ma, Likkuen<sup>{\textdagger}</sup> and Lin Zhang and Guo, Yikun and Li, Yunke and Yu, Han and Ma, Wei and Yan, He* and <strong>Zhao, Dahui*</strong>}
}
