Despite remarkable advancement made by virtue of “polymerized non-fullerene acceptor” strategy in all-polymer solar cells (all-PSCs) recently, the tuning of polymer crystallinity via molecular design to optimize the nanostructured blend morphology remains challenging for boosting the short-circuit current density (JSC). Herein, through systematically optimizing the central core and π-spacer, we present a facile method to regulate the solid-state crystallinity of these emerging polymer acceptors. Specifically, we have synthesized a new family of polymerized non-fullerene acceptors named PY-2T and PY-2T2Cl by copolymerizing the Y5-derivative with bithiophene or chlorinated bithiophene. Compared to the previously used IDIC-based polymer named PIDIC-2T, the extended D-A-D fused ring core renders PY-2T with significantly red-shifted optical absorption and up-shifted energy levels, leading to simultaneously improved JSC and open circuit voltage (VOC) in the resultant all-PSCs. More importantly, the chlorinated PY-2T (PY-2T2Cl) endows the desirable phase separated blend morphology with favorable film crystallinity when paired with polymer donor PBDB-T, thus PY-2T2Cl based all-PSCs delivers a promising power conversion efficiency of approaching ~10% with a greatly enhanced JSC of 16.3 mA/cm2 and high VOC of 0.87 eV. This systematic study provides an insight into the effect of central core and π-spacer on the film crystallinity for developing high-performance polymerized non-fullerene acceptors, and also highlights the importance of both absorption and morphology in boosting the desired JSC in all-PSCs.
Bibliographical noteFunding Information:
This work was supported by the National Natural Science Foundation of China (Grant No. 21905225, 52073198 and 51803144), the Science and Technology Program of Shaanxi Province (2019JQ-244 and 2019JQ-076), the Outstanding Youth Science and Technology Foundation of Xi’an University of Science and Technology (2019YQ3-03), the China Postdoctoral Science Foundation (Grant No. 2019M651942) and “111” projects. The author thanks the Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University. H.Y.W. is thankful for the financial support from the National Research Foundation (NRF) of Korea (NRF-2016M1A2A2940911 and 2019R1A6A1A11044070).
- All-polymer solar cells
- Central core
- Chlorinated π-spacer
- Photovoltaic performance
- Polymerized non-fullerene acceptor
ASJC Scopus subject areas
- Environmental Chemistry
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering