Comprehensive passivation strategy for achieving inverted perovskite solar cells with efficiency exceeding 23% by trap passivation and ion constraint. (November 2021)

• Record Type: Journal Article
• Authors: Zhang, Fan; Ye, Shuai; Zhang, Hanhong; Zhou, Feifan; Hao, Yuying; Cai, Houzhi; Song, Jun; Qu, Junle
• Is Part Of: Nano energy. Volume 89(2021)Part A
• Publication Date: 2021-11
• Subjects: Interfacial-passivation -- Inverted perovskite solar cells -- Trap passivation -- Ion fetter -- Long-term stability; 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.2021.106370
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Both surface and bottom of perovskite film suffer from high density of trap-assisted recombination losses in perovskite solar cells; therefore, an effective method suitable for minimizing the trap density of perovskite solar cells (PSCs) both at perovskite/hole transport layer interfaces and perovskite/electron transport layer is urgently required. Herein, a comprehensive passivation strategy for achieving high-performance inverted PSCs was demonstrated. The study shows that the inverted PSCs possess dual increase of efficiency by passivation of the surface and bottom, as well as grain boundaries of perovskite active layer. The unencapsulated PSCs from comprehensive passivation strategy achieved the highest power conversion efficiency of 23.33% with remarkable long-term stability when exposed to illumination and humidity. In addition, this work provides an original method to analyze the distribution of the interfacial trap density and ions accumulation density by using the combination process of capacitance–voltage (C-V) and drive-level capacitance profiling (DLCP) measurements, providing the direct evidence for reducing of trap density and inhibiting of ion accumulation at two interfaces of PSCs. Graphical Abstract: A double-passivation strategy was demonstrated, which enabled the inverted PSCs to achieve dual improvement of open-circuit voltage from effective passivation of both the surface and bottom of perovskite active layer. The unencapsulated double-passivation PSCs achieved the highest power conversion efficiency of 23.33% with remarkable long-term stability when exposed to illumination and humidity. ga1 Highlights: Power conversion efficiency of over 23.33% with remarkable long-term stability was obtained based on unencapsulated PSCs from comprehensive passivation strategy. An n–n isotype heterojunction was formatted to not only optimize the local electric field distribution at the junction but also assisted the ion constraint. A thin PMMA layer was inserted at bottom of perovskite to suppress the deep traps at HTL/perovskite interface and facilitate the rebalancing of charge-transport. An original method was provided to analyze the distribution of the interfacial trap density and ions accumulation density by using the combination process of C–V and DLCP measurements.