Organic Tetrabutylammonium Cation Intercalation to Heal Inorganic CsPbI₃ Perovskite

Abstract

The in situ formation of reduced dimensional perovskite layer via post‐synthesis ion exchange has been an effective way of passivating organic‐inorganic hybrid perovskites. In contrast, cesium ions in Cs‐based inorganic perovskite with strong ionic binding energy cannot exchange with those well‐known organic cations to form reduced dimensional perovskite. Herein, we demonstrate that tetrabutylammonium (TBA+) cation can intercalate into CsPbI3 to effectively substitute the Cs cation and to form one‐dimensional (1D) TBAPbI3 layer in the post‐synthesis TBAI treatment. Such TBA cation intercalation leads to in situ formation of TBAPbI3 protective layer to heal defects at the surface of inorganic CsPbI3 perovskite. The TBAPbI3‐CsPbI3 perovskite exhibited enhanced stability and lower defect density, and the corresponding perovskite solar cell devices achieved an improved efficiency up to 18.32 % compared to 15.85 % of the control one.

Highly Efficient and Stable CsPbTh3 (Th = I, Br, Cl) Perovskite Solar Cells by Combinational Passivation Strategy

“…[24] Steele et al reported that the introduction of substrate clamping and biaxial strain could induce crystal distortions and texture formation within black CsPbI 3 thin films, which were thermodynamically stable after being aged under ambient condition. [25] Besides, cation engineering such as phenylethylammonium (PEA + ), [26] ethylenediamine (EDA + ), [27] tetrabutylammonium (TBA + ), [28] Ca 2+ , [29] Sn 2+ [30] is regarded as an effective way to increase the tolerance factor and reduce the trap state density which can stabilize the black phase and improve the efficiency. We recently found that incorporating a small amount of Br and Cl into CsPbI 3 film (marked as CsPbTh 3 ) exhibited an optimized carrier dynamics performance than pure CsPbI 3 perovskite due to their higher electronegativity and ionization potential than I.…”

Temperature‐Reliable Low‐Dimensional Perovskites Passivated Black‐Phase CsPbI3 toward Stable and Efficient Photovoltaics

“…Especially when exposed to moisture, the black‐phase CsPbI 3 quickly turns into the yellow‐phase CsPbI 3 (δ‐CsPbI 3 ), which largely limits the cell performance of CsPbI 3 PSCs [3b, 8] . Some strategies have been exploited to stabilize the photoactive black‐phase CsPbI 3 , such as interfacial modification, [4b, 9] additive incorporation, [10] reducing crystal sizes [11] and dimensional engineering [8a, 12] . Interface modification can effectively prevent ambient moisture invasion and simultaneously passivate interface defects; however, bulk defects of CsPbI 3 films still have considerable influence on device performance.…”

Strategies for highly efficient and stable cesium lead iodide perovskite photovoltaics: mechanisms and processes

“…6l. 104 The experiment showed that tetrabutylammonium (TBA + ) ions can intercalate and repair CsPbI 3 with organic cations through the ion exchange reaction. This cation can intercalate into the PbI 6 4− octahedral structure and exchange the Cs + ; thus the two connected layers fractured and the 3D perovskite structure collapsed and then a 1D TBAPbI 3 protective layer was in situ formed.…”