Cs2SnI6perovskite displays excellent air stability and a high absorption coefficient, promising for photovoltaic and optoelectronic applications. However, Cs2SnI6‐based device performance is still low as a result of lacking optimized synthesis approaches to obtain high quality Cs2SnI6crystals. Here, a new simple method to synthesize single crystalline Cs2SnI6perovskite at a liquid–liquid interface is reported. By controlling solvent conditions and Cs2SnI6supersaturation at the liquid–liquid interface, Cs2SnI6crystals can be obtained from 3D to 2D growth with controlled geometries such as octahedron, pyramid, hexagon, and triangular nanosheets. The formation mechanisms and kinetics of complex shapes/geometries of high quality Cs2SnI6crystals are investigated. Freestanding single crystalline 2D nanosheets can be fabricated as thin as 25 nm, and the lateral size can be controlled up to sub‐millimeter regime. Electronic property of the high quality Cs2SnI62D nanosheets is also characterized, featuring a n‐type conduction with a high carrier mobility of 35 cm2V−1s−1. The interfacial reaction‐controlled synthesis of high‐quality crystals and mechanistic understanding of the crystal growth allow to realize rational design of materials, and the manipulation of crystal growth can be beneficial to achieve desired properties for potential functional applications.
Air‐stable p‐type SnF2:Cs2SnI6with a bandgap of 1.6 eV has been demonstrated as a promising material for Pb‐free halide perovskite solar cells. Crystalline Cs2SnI6phase is obtained with CsI, SnI2, and SnF2salts in gamma‐butyrolactone solvent, but not with dimethyl sulfoxide and
- NSF-PAR ID:
- 10441958
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Solar RRL
- Volume:
- 7
- Issue:
- 19
- ISSN:
- 2367-198X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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