Constructing continuous acceptor fibrillar networks and achieving uniform phase separation via polymer-assisted morphology control for 20.3% efficiency additive-free organic solar cells
Journal article, 2025
Additive-free organic solar cells (OSCs) represent a critical advancement toward scalable, stable photovoltaic devices by eliminating processing complexities associated with solvent additives. However, achieving an optimal active-layer morphology in their absence remains a formidable challenge. Here, we introduce a polymer engineering strategy to enhance morphological control and device performance in additive-free OSCs. By incorporating a small fraction of the polymer acceptor PY-DT into the D18:L8-BO blend system, we demonstrate that PY-DT acts as a nucleating agent during film formation, promoting the ordered molecular stacking of L8-BO. The polymer's rigid backbone further directs epitaxial growth of the L8-BO phase, driving the formation of a continuous fibrillar network within the acceptor domain and enabling uniform phase separation. This hierarchical assembly enhances exciton dissociation and balances charge transport, yielding a champion power conversion efficiency (PCE) of 20.3%, which is one of the highest values for additive-free OSCs. Stability evaluations reveal that devices retain 85.3% of their initial efficiency after 1200 hours of continuous illumination. Our findings establish a novel approach to morphological engineering in additive-free OSCs, offering a pathway toward industrially viable, high-performance devices and advancing the field of organic photovoltaics.
Author
Fengbo Sun
Shandong University
Jingnan Wu
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Bo Cheng
Shandong University
Lixuan Kan
Shanghai Jiao Tong University
Feng Hua
Shandong University
Wei Sun
Shandong University
Hao Wang
Shandong University
Yumiao Huo
Shandong University
Sixuan Chen
Shandong University
Xinxin Xia
Shandong University
Xiaoyan Du
Shandong University
Feng Liu
Shanghai Jiao Tong University
Ergang Wang
Chalmers, Chemistry and Chemical Engineering
Xia Guo
Shandong University
Yongfang Li
Soochow University
Maojie Zhang
Shandong University
Soochow University
Energy and Environmental Sciences
1754-5692 (ISSN) 17545706 (eISSN)
Vol. 18 14 7071-7081Subject Categories (SSIF 2025)
Materials Chemistry
Condensed Matter Physics
DOI
10.1039/d5ee01843a