Regulating the Aggregation of Unfused Non‐Fullerene Acceptors via Molecular Engineering towards Efficient Polymer Solar Cells
Abstract
Tuning molecular aggregation via structure design to manipulate the film morphology still remains as a challenge for polymer solar cells based on unfused non‐fullerene acceptors (UF‐NFAs). Herein, a strategy was developed to modulate the aggregation patterns of UF‐NFAs by systematically varying the π‐bridge (D) unit and central core (A’) unit in A−D‐A’−D−A framework (A and D refer to electron‐withdrawing and electron‐donating moieties, respectively). Specifically, the quantified contents of H‐ or J‐aggregation and crystallite disorder of three UF‐NFAs (BDIC2F, BCIC2F, and TCIC2F) were analyzed via UV/Vis spectrometry and grazing incidence X‐ray scattering. The results showed that the H‐aggregate‐dominated BCIC2F with less crystallite disorder exhibited a more favorable blend morphology with polymer donor PBDB‐T (poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b']dithiophene)‐co‐(1,3‐di(5‐thiophene‐2‐yl)‐5,7‐bis(2‐ethylhexyl)benzo[1,2‐c:4,5‐c']dithiophene‐4,8‐dione)]) relative the other two UF‐NFAs, resulting in improved exciton dissociation and charge tranport. Consequently, photovoltaic devices based on BCIC2F delivered a promising power conversion efficiency of 12.4 % with an exceptionally high short‐circuit current density of 22.1 mA cm−2.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 26, 2021
- Source ID
- 10.1002/cssc.202100746
Entities
People
- Alex K.‐y. Jen
- Francis Lin
- Han Young Woo
- Hongmei Qin
- Huiting Fu
- Mei Wang
- Xin Wu
- Yuxiang Li
- Ziang Wu
Organizations
- City University of Hong Kong
- Korea University
- Office of Naval Research
- School of Materials, University of Manchester
- University of Washington