Degradation Studies of Cs₃Sb₂I₉: A Lead-Free Perovskite

Abstract

Lead-free halide perovskites have attracted interest in the photovoltaic industry out of concern for the toxic nature of the lead. Antimony-based perovskite, cesium antimony iodide (Cs3Sb2I9), is one such material proposed to substitute the lead-based perovskites, as it has a high absorption coefficient, nearly direct bandgap, and low effective mass. A clear understanding of the stability of this material will bring out its efficient use in photovoltaics. Here we have studied the degradation of both the polymorphs of Cs3Sb2I9 (dimer and layer forms) in water, light, and elevated temperaturethe well-known factors causing degradation in perovskites using X-ray diffraction and thermogravimetric analysis. The layered polymorph is found to be more stable compared to the dimer polymorph. The dimer form completely degrades in ∼49 days and the layer form in ∼88 days, although both polymorphs of Cs3Sb2I9 are relatively more stable than the established organic–inorganic halide perovskites. We found that the diffusion of iodine from the system is the prime reason for the degradation in Cs3Sb2I9. Also, the reactivity of antimony iodide (SbI3) in oxygen adds up to accelerate the degradation process. Light, water, and heat equally cause the degradation of Cs3Sb2I9, and hence, use of this material for application in the ambient atmosphere would need proper encapsulation or necessary measures.

Efficiency improvement for perovskite-inspired Cs3Sb2I9 solar cells using P3HT as the hole transport material

“…According to literature the layered form of Cs 3 Sb 2 I 9 has good stability in ambient conditions while the dimer form degrades more rapidly. 9,24,31 It is possible that some of the films that we monitored in this work were not fully converted to the 2D layered form. We monitored a rather large set of solar cells (38 devices in total) therefore it is likely that some of the devices contain imperfections such as incomplete crystallization.…”

Enhanced visible light absorption in layered Cs3Bi2Br9 through mixed-valence Sn(ii)/Sn(iv) doping

“…9 Both theoretical and experimental investigations have found that for a given composition, this 2D layered A 3 B 2 X 9 polymorph exhibits a narrower band gap, higher electron and hole mobility, larger dielectric constants, and corresponding better defect tolerance, 20,21 as well as enhanced stability towards degradation, compared with the other A 3 B 2 X 9 structures. 22 This likely renders the layered form more suitable than the 1D chain or 0D dimer counterparts for optoelectronic applications including photovoltaics and lighting. However, the 2D layered structure only forms for a few compositions, most commonly bromides and chlorides such as Cs 3 Bi 2 Br 9 , Cs 3 Sb 2 Br 9 and Cs 3 Fe 2 Cl 9 .…”

Recent Advances and Opportunities of Lead-Free Perovskite Nanocrystal for Optoelectronic Application

“…Antimony-(Sb-) based halide perovskites are a potential alternative to leadbased counterparts for optoelectronic applications to address the chemical stability and toxicity issues. Analogous to Bi 3+based perovskites, the trivalent Sb 3+ is isoelectronic with divalent Pb 2+ cations and possesses similar electronegativity [146][147][148][149][150][151][152]. Additionally, the similarity of the electronic configuration of A 3 Sb 2 X 9 (A = MA + , Cs + , or Rb + ) to the leadhalide perovskites suggests the important advantages of such materials [153][154][155][156][157].…”

“…Additionally, the similarity of the electronic configuration of A 3 Sb 2 X 9 (A = MA + , Cs + , or Rb + ) to the leadhalide perovskites suggests the important advantages of such materials [153][154][155][156][157]. For Sb-containing perovskites, the chemical formula A 3 Sb 2 I 9 is known to exhibit 0D and 2D crystal structures [148]. The preferred formation of 0D and 2D structures depends on the sample preparation technique and the ligand selection.…”