Highly Stable Two‐Dimensional Tin(II) Iodide Hybrid Organic–Inorganic Perovskite Based on Stilbene Derivative

Abstract

Hybrid organic-inorganic perovskites have recently emerged as potential disruptive photovoltaic technology. However, the toxicity of lead used in state-of-the-art hybrid perovskites solar cell prevents large-scale commercialization, which calls for lead-free alternatives. Sn-based perovskites have been considered as alternatives but they are limited by rapid oxidation and decomposition in ambient air. Here, an Sn-based two-dimensional hybrid organic-inorganic perovskites [A 2 B (n-1) Sn n I (3n+1) ] (n = 1 and 2) are reported with improved air stability, using bulky stilbene derivatives as the organic cations (2-(4-(3-fluoro)stilbenyl)ethanammonium iodide (FSAI)). The moisture stability of the [(FSA) 2 SnI 4 ] perovskites is attributed to the hydrophobic properties of fluorine-functionalized organic chains (FSA), as well as the strong cohesive bonding in the organic chains provided by H bonds, CH···X type H bonds, weak interlayer F···F interaction, and weak face-to-face type π-π interactions. The photodetector device fabricated on exfoliated single crystal flake of [(FSA) 2 SnI 4 ] exhibits fast and stable photoconductor response.

Strategies for Improving the Stability of Tin‐Based Perovskite (ASnX3) Solar Cells

“…[ 125 ] However, LD tin‐based perovskites on different additives and reducing agents have commanded less research, allowing for more explorations on their applications. [ 119 ] Meanwhile, the development of new LD materials, such as (2‐(4‐(3‐fluoro)stilbenyl) ethanammonium iodide (FSAI)), [ 135 ] is another strategy to further improve their performance in the future. Finally, there are a few studies on Dion–Jacobson and interlayer space in tin‐based PSCs, pointing us to a new development path. Exploring compact inorganic transport layer.…”

Tin Halide Perovskites: Progress and Challenges

“…Moreover, as shown in Figure f, a coaddition of pyrazine and SnF 2 can effectively subdue surface phase separation leading to a more homogenous film . Functionalized organic chains such as that of 2‐(4‐(3‐fluoro)stilbenyl)ethanammonium iodide (FSAI) can also ensure moisture resistance and strong cohesive bonding interactions in the 2D structure . Overall, SnF 2 is the most widely used additive in Sn halide perovskite preparation.…”

Two‐Dimensional Metal‐Halide Perovskite‐based Optoelectronics: Synthesis, Structure, Properties and Applications

“…In this case, Sn‐based 2D perovskites have been identified as suitable alternatives, while they are still hindered by the instability in the air environment. [ 50 ] Loh et al [ 51 ] reported a Sn‐based hybrid organic–inorganic 2D perovskite of (FSA) 2 SnI 4 with enhanced air stability, using 2‐(4‐(3‐fluoro)stilbenyl)ethanammonium (FSA + ) as the organic cations. The water instability of (FSA) 2 SnI 4 perovskite is ascribed to the water resistance of fluorinated organic chains, as a concrete effect of strongly cohesive bonding contained the H bonding, CH‐X type of H bonding, weak interlayer of F‐F interactions, and weak aspectant type of π‐π interaction.…”