Nearly-Zero Thermal Expansion Along the Layer-Stacking Axis of ZnSe-Based Inorganic–Organic Hybrid Semiconductor Materials



Zero thermal expansion (ZTE) is a desired but rare material property. Herein we report a unique family of inorganic–organic hybrid semiconductors with general formula [ZnSe(L)0.5] (L = organic diamine) that exhibit nearly-zero thermal expansion along the layer-stacking axis in the temperature range of 5–300 K. The unit cell parameters and crystal structures of [ZnSe(en)0.5], [ZnSe(pda)0.5], [ZnSe(bda)0.5], and [ZnSe(ptda)0.5] (en = ethylenediamine, pda = propanediamine, bda = butanediamine, and ptda = pentanediamine) have been refined by the Rietveld method by using powder samples, and their thermal expansion properties have been analyzed and rationalized on the basis of their crystal structures and symmetry. [ZnSe(ptda)0.5] features a very small negative linear thermal expansion coefficient (–7.8 × 10–7 K–1) that approaches the smallest values reported to date.