Toward High Efficiency Polymer Solar Cells: Influence of Local Chemical Environment and Morphology
Abstract
The chemical structure of conjugated polymers plays an important role in determining their physical properties that, in turn, dictates their performance in photovoltaic devices. 5‐Fluoro‐2,1,3‐benzothiadiazole, an asymmetric unit, is incorporated into a thiophene‐based polymer backbone to generate a hole conducting polymers with controlled regioregularity. A high dipole moment is seen in regioregular polymers, which have a tighter interchain stacking that promotes the formation of a morphology in bulk heterojunction blends with improved power conversion efficiencies. Aliphatic side chain substitution is systematically varied to understand the influence of side chain length and symmetry on the morphology and resultant performance. This side chain modification is found to influence crystal orientation and the phase separated morphology. Using the asymmetric side chain substitution with regioregularity of the main chain, an optimized power conversion efficiency of 9.06% is achieved, with an open circuit voltage of 0.72 V, a short circuit current of 19.63 mA cm−2, and a fill factor over 65%. These results demonstrate that the local chemical environment can dramatically influence the physical properties of the resultant material.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 22, 2016
- Source ID
- 10.1002/aenm.201601081
Entities
People
- Cheng Zhou
- Chengmei Zhong
- Fei Huang
- Feng Liu
- Guichuan Zhang
- Ke Gao
- Peng Luo
- Rongguo Xu
- Thomas Paul Russell
- Xiaoe Jia
- Xiaofang Jiang
- Yong Cao
Organizations
- Lawrence Berkeley National Laboratory
- Ministry of Science and Technology of the People's Republic of China
- National Natural Science Foundation of China
- Shanghai Jiao Tong University
- University of Massachusetts