Unraveling the compositional heterogeneity and carrier dynamics of alkali cation doped 3D/2D perovskites with improved stability. Issue 4 (5th January 2021)

• Record Type: Journal Article
• Authors: Tang, Ming-Chun; Zhang, Siyuan; Magnanelli, Timothy J.; Nguyen, Nhan V.; Heilweil, Edwin J.; Anthopoulos, Thomas D.; Hacker, Christina A.
• Is Part Of: Materials advances. Volume 2:Issue 4(2021)
• Page Start: 1253
• Page End: 1262
• Publication Date: 2021-01-05
• Subjects: 620.11
• DOI: 10.1039/d0ma00967a
• Languages: English
• ISSNs: 2633-5409

Abstract

Abstract : A comprehensive analysis of the compositional heterogeneity and carrier dynamics in novel rubidium-doped 3D/2D perovskites is investigated, showing a PCE over 20% and improved stability at ≈50% relative humidity without encapsulation. Abstract : Preventing the degradation of hybrid perovskites by humid air remains a challenge for their future commercial utilization. 3D/2D perovskites with hierarchical architecture have attracted significant attention due to their promising power conversion efficiency (PCE) and device stability. Here, we report a novel 3D/2D planar bi-layer perovskite obtained by growing a 2D Ruddlesden–Popper layer on top of a 3D rubidium (Rb + )-doped triple-cation perovskite. Rb + cation incorporation decreases the work function, and 3D/2D films show smaller work function values compared to classic 3D perovskites. X-ray photoemission spectroscopy (XPS) confirms the presence of a 2D perovskite capping layer and observes halide migration. Time-resolved terahertz spectroscopy (TRTS) shows that the average DC carrier mobility for the 3D/2D hierarchical structures and their 3D counterparts is one order of magnitude higher than that for the 2D perovskite. The resulting 3D/2D Rb + -incorporated perovskite solar cells show a peak PCE of >20%, which is slightly higher than their 3D counterparts (19.5%). Benefiting from moisture resistivity, the 3D/2D perovskite photovoltaics show significantly improved long-term stability by retaining 81% of the initial PCE after 60 days of exposure to ambient air (50 ± 10% relative humidity) without encapsulation, highlighting the potential of engineered stable 3D/2D perovskite solar cells for their commercial utilization.