Spontaneous grain polymerization for efficient and stable perovskite solar cells

• Published in: Nano energy 2019-04, Vol.58, p.825-833
• Main Authors: Li, Xiaodong, Zhang, Wenxiao, Zhang, Wenjun, Wang, Hai-Qiao, Fang, Junfeng
• Format: Article
• Language: English
• Subjects: Defects passivation; Grain boundary; Perovskite solar cells; Spontaneous polymerization; Stability
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2019.02.009

Spontaneous grain polymerization strategy is proposed to fabricate efficient and stable perovskite solar cells (PSCs) through the incorporation of polymerizable additive ethyl 2-cyanoacrylate (E2CA). E2CA lies in and chemically anchors to grain boundaries (GBs) owing to –CN and -C=O groups’ coordination with PbI2, thus passivating the defects at GBs and leading to high devices efficiency of 21.03%. Importantly, E2CA in perovskite films will spontaneously polymerize to a hydrophobic polymer at GBs when exposed in moisture air, thus blocking GBs channel for moisture penetration and enhancing the moisture-resisting properties of perovskite films. As a result, PSCs with E2CA exhibit superior stability in moisture air (relative humidity: 40–60%), retaining ~90% of the maximum efficiency after aging over 1000 h. Even under high temperature (85 °C) in moisture air, non-encapsulated MAPbI3-E2CA devices still show good stability despite the burn-in degradation, retaining over 90% of the post burn-in efficiency after aging 200 h. Spontaneous grain polymerization strategy is proposed to fabricate efficient and stable perovskite solar cells through the incorporation of ethyl 2-cyanoacrylate (E2CA) additive. E2CA chemically anchors to grain boundaries and then spontaneously polymerizes to hydrophobic polymer when exposed in air, thus passivating defects and blocking moisture penetration. The resulted devices exhibit high efficiency of 21.03% with good air and thermal stability. [Display omitted] •Spontaneous grain polymerization strategy is proposed to fabricate PSCs through using polymerizable additive (E2CA).•E2CA anchors to grain boundaries and then polymerizes to a hydrophobic polymer, thus enhancing the stability of PSCs.•The PSCs exhibit high efficiency of over 21% with good stability, retaining ~90% of their initial efficiency after 1000 h.