Realizing 19.05% Efficiency Polymer Solar Cells by Progressively Improving Charge Extraction and Suppressing Charge
Kaien Chong1, Xiaopeng Xu2, Huifeng Meng2
1College of Chemistry, Key Laboratory of Green Chemistry and Technology of the Ministry of Education and State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065, P. R. China.
Advanced Materials (Deerfield Beach, Fla.)
|January 26, 2022
Summary
Highly efficient polymer solar cells (PSCs) were achieved by optimizing nonfullerene acceptors (NFAs) and blend morphology. This strategy improved charge extraction and reduced recombination, leading to a record power conversion efficiency (PCE).
Area of Science:
- Materials Science
- Organic Electronics
- Photovoltaics
Background:
- Minimizing photon loss in polymer solar cells (PSCs) requires efficient charge extraction and suppressed charge recombination.
- Nonfullerene acceptors (NFAs) are crucial components in advancing PSC performance.
- Ternary blends and additives can fine-tune morphology and charge dynamics in PSCs.
Purpose of the Study:
- To enhance the performance of polymer solar cells (PSCs) through improved charge extraction and reduced charge recombination.
- To investigate the effects of side-chain engineering in NFAs on molecular packing and phase separation.
- To optimize blend morphology using ternary blends and volatilizable solid additives for higher power conversion efficiency (PCE).
Main Methods:
- Synthesized and characterized new nonfullerene acceptors (NFAs) with modified side chains (BTP-Th and BTP-FTh).
- Employed ternary blend strategies incorporating a second acceptor and a volatilizable solid additive.
- Fabricated and tested polymer solar cells (PSCs) to evaluate device performance metrics like fill factor (FF), open-circuit voltage (Voc), short-circuit current density (Jsc), and power conversion efficiency (PCE).
Main Results:
- Fluorination of NFA side chains (BTP-FTh) mitigated steric hindrance and improved molecular packing compared to BTP-Th.
- The introduction of a second crystalline acceptor and a volatilizable solid additive significantly enhanced blend crystallinity and optimized morphology.
- Achieved progressive improvements in charge extraction and suppression of charge recombination, leading to a record PCE of 19.05%.
Conclusions:
- Side-chain engineering of NFAs, combined with ternary blending and additive strategies, effectively enhances PSC performance.
- Optimized molecular packing and morphology are key to improving charge extraction and reducing recombination losses.
- The developed approach demonstrates a promising pathway for achieving high-efficiency polymer solar cells.
