Fine coverage and uniform phase distribution in 2D (PEA)2Cs3Pb4I13 solar cells with a record efficiency beyond 15%. (February 2022)

• Record Type: Journal Article
• Authors: Yao, Huanhuan; Peng, Guoqiang; Li, Zhizai; Wang, Qian; Xu, Youkui; Ma, Bo; Lei, Yutian; Wang, Gang; Wang, Qiang; Ci, Zhipeng; Zhang, Hao-Li; Jin, Zhiwen
• Is Part Of: Nano energy. Volume 92(2022)
• Publication Date: 2022-02
• Subjects: Ruddlesden-popper -- 2D CsPbI3 -- Underlying surface engineering -- Crystallization kinetics -- Gradient phase distribution; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2021.106790
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: By introducing phenylethylammonium cation (PEA + ) as steric hindrance, the two-dimensional (2D) Ruddlesden-Popper (RP) (PEA)2 (Cs)n−1 Pbn I3n+1 (n ≤ 5) exhibits much stronger phase stability than 3D CsPbI3 . However, uncontrollable crystallization process leads to poor coverage and unfavorable phase management in the final (PEA)2 (Cs)n−1 Pbn I3n+1 film, resulting in low power conversion efficiency (PCE < 10%) and poor stability of the related perovskite solar cells (PSCs). Here, we propose an underlying surface engineering (USE) method, which improves the wettability of the substrate and promotes the diffusion of the precursor solution to fabricate a high-quality film with high coverage and low defect density. Further characterizations confirm that this method enables a more uniform phase distribution and achieves an orderly arrangement of small-n and large-n phases from bottom to surface in film, which contributes to effective charge transfer to enhance photocurrent transmission and extraction. As a result, the PCE of (PEA)2 Cs3 Pb4 I13 PSCs was boosted from initial 9.03% to a record value of 15.92%, accompanied by enhanced stability. Encouragingly, this method also has versatility in other RP and Dion-Jacobson (DJ) types of 2D CsPbI3 PSCs, paving a broad road for its commercial application in the future. Graphical Abstract: ga1 This work mainly focus on using underlying surface engineering (USE) method to improve the wettability of the substrate to fabricate a high-quality film, and introduce PEA + to achieve gradient phase distribution. Importantly, 2D (PEA)2 Cs3 Pb4 I13 PSCs achieved a record-breaking 15.92% PCE, accompanied by enhanced stability. Meanwhile, the method also has versatility in other RP and DJ type devices. Highlights: The USE methods improves the wettability of the substrate and promotes the diffusion of the precursor solution. By introducing PEA +, the phase distribution is more uniform and finer, and the effective carrier extraction is realized. The PCE of (PEA)2 Cs3 Pb4 I13 PSCs was boosted from initial 9.13% to 15.92%, accompanied by strengthened stability. This method has versatility in other RP and DJ types of 2D CsPbI3 PSCs, paving way for commercial applications.