Isomery‐Dependent Miscibility Enables High‐Performance All‐Small‐Molecule Solar Cells
Abstract
Nonfullerene polymer solar cells develop quickly. However, nonfullerene small‐molecule solar cells (NF‐SMSCs) still show relatively inferior performance, attributing to the lack of comprehensive understanding of the structure–performance relationship. To address this issue, two isomeric small‐molecule acceptors, NBDTP‐Fout and NBDTP‐Fin, with varied oxygen position in the benzodi(thienopyran) (BDTP) core are designed and synthesized. When blended with molecular donor BDT3TR‐SF, devices based on the two isomeric acceptors show disparate photovoltaic performance. Fabricated with an eco‐friendly processing solvent (tetrahydrofuran), the BDT3TR‐SF:NBDTP‐Fout blend delivers a high power conversion efficiency of 11.2%, ranked to the top values reported to date, while the BDT3TR‐SF:NBDTP‐Fin blend almost shows no photovoltaic response (0.02%). With detailed investigations on inherent optoelectronic processes as well as morphological evolution, this performance disparity is correlated to the interfacial tension of the two combinations and concludes that proper interfacial tension is a key factor for effective phase separation, optimal blend morphology, and superior performance, which can be achieved by the “isomerization” design on molecular acceptors. This work reveals the importance of modulating the materials miscibility by interfacial‐tension‐oriented molecular design, which provides a general guideline toward efficient NF‐SMSCs.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Dec 03, 2018
- Source ID
- 10.1002/smll.201804271
Entities
People
- Haijun Fan
- Hao Wu
- Harald Ade
- Long Ye
- Shengjie Xu
- Xiaozhang Zhu
- Yuan Guo
- Yuanping Yi
Organizations
- Chinese Academy of Sciences
- Institute of Chemistry
- National Natural Science Foundation of China
- North Carolina State University
- Office of Naval Research
- University of Chinese Academy of Sciences