New layered organic-inorganic superlattice with bilayer linear molecules for superhigh heat insulation

Layered inorganic materials provide an essential platform for constructing new structural configurations of materials with exceptional properties. However, precise control over the interlayer molecular arrangement remains a significant challenge, impeding in-depth exploration in physics and chemistry realm. Herein, we demonstrated a new layered organic-inorganic superlattice composed of a S-Ta-S inorganic lattice and bilayer linear molecules, providing superhigh heat insulation. A series of interlayer-confined intercalations of alkylamines with increasing chain length in the layered inorganic materials were achieved through precisely ordered molecule design (TaS₂-Cn, n = 3, 6, 8, 12). Systematic spectral analysis reveals that as the length of the intercalated alkyl chain increases, the alkyl chain between layers becomes more ordered and linear, and the gauche conformation decreases. Furthermore, the more linear and ordered alkyl chain conformation results in lower thermal conductivity. The thermal conductivity of TaS₂-C12 is 0.426 W m⁻¹ K⁻¹, which is only one-third that of the pristine TaS₂ crystal. We anticipate that this layered organic-inorganic superlattice design will pave a new avenue for developing new organic-inorganic functional materials and probing the limits of ultralow thermal conductivity materials.