Simultaneously Enhanced Efficiency and Mechanical Durability in Ternary Solar Cells Enabled by Low‐Cost Incompletely Separated Fullerenes

• Published in: Macromolecular rapid communications. Vol. 43; no. 22; pp. e2200139 - n/a
• Main Authors: Sun, Yanna, Ma, Ruijie, Kan, Yuanyuan, Liu, Tao, Zhou, Kangkang, Liu, Pengke, Fang, Jin, Chen, Yiyao, Ye, Long, Ma, Changqi, Yan, He, Gao, Ke
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.11.2022
• Subjects: all‐polymer solar cells; Carrier mobility; Carrier recombination; Charge transport; Competitiveness; Crystallization; Current carriers; Ductility; Durability; Electron mobility; Energy conversion efficiency; fullerene; Fullerenes; low cost; mechanical ductility; Mobility; Photovoltaic cells; Photovoltaics; Polymer blends; Polymers; Recombination; Solar cells; Strain; ternary solar cells; Ternary systems; mechanical ductility; ternary solar cells; low cost; fullerene; all-polymer solar cells
• ISSN: 1022-1336; 1521-3927; 1521-3927
• DOI: 10.1002/marc.202200139

All‐polymer solar cells (all‐PSCs) are one of the most promising application‐oriented organic photovoltaic technologies due to their excellent operational and mechanical stability. However, the power conversion efficiencies (PCEs) are mostly lower than 16%, restricting their core competitiveness. Furthermore, the improvement of mechanical durability is rarely paid attention to cutting‐edge all‐PSCs. This work deploys a low‐cost “technical grade” PCBM (incompletely separated but pure mixtures containing ≥90% [70]PCBM or [60]PCBM), into the efficient PM6:PY‐IT all‐polymer blend, successfully yielding a high‐performance ternary device with 16.16% PCE, among the highest PCE values for all‐PSCs. Meanwhile, an excellent mechanical property (i.e., crack onset strain = 11.1%) promoted from 9.5% for the ternary system is also demonstrated. The “technical grade” PCBM slightly disrupts the crystallization of polymers, and disperses well into the amorphous polymer regions of the all‐PSC blends, thus facilitating charge transport and improving film ductility simultaneously. All these results confirm introducing low‐cost “technical grade” PCBM with high electron mobility into all‐polymer blends can improve carrier mobility, reduce charge recombination, and optimize morphology of the amorphous polymer regions, thus yielding more efficient and mechanically durable all‐PSCs. Both improved mechanical durability and efficiency are achieved in the all‐polymer solar cells (all‐PSCs) with low‐cost incompletely separated fullerenes. A power conversion efficiency (PCE) of 16.16% for the ternary device is obtained, significantly higher than those of binary systems, which is among the highest values of all‐PSCs. "Technical grade" fullerenes (Tech‐PCBM) slightly disrupt the crystallization of polymers, and disperses well into the amorphous polymer regions of the all‐PSC blends, thus facilitating charge transport and improving film ductility simultaneously.