[Fe(bpy)3]2Ag6Br11.NO3: Synthesis, Crystal Structure and Unusual Photo-conductance

Abstract

Organic-inorganic metal halide hybrids, especially those containing silver(I) halides, have gained significant attention due to their remarkable structural diversity and unique optoelectronic properties. The exceptional performance of these materials results from the synergistic interaction between the organic and inorganic components, which enhances overall functionality. In this research, we report the synthesis of a novel Ag(I)-based organic-inorganic hybrid crystal, where the transition metal complex [Fe(bpy)3] +3 (bpy = 2,2´-bipyridine) with Fe(III) serves as a structure-directing agent (SDA). The complex directs the formation of a 2D polymeric chain of anionic (Ag6Br11)n 5n layers. The resulting crystal, [Fe(bpy)3]2Ag6Br11.NO3, exhibits a distinctive Ag···Ag bond distance of 2.989 Å, confirming the presence of strong argentophilic interactions. Notably, the material demonstrates an exceptional photo-response, with a photocurrent increase of more than three orders of magnitude under light irradiation (10- 12 to 10-9 ). This enhancement is attributed to the combined effect of argentophilic interactions in the anionic framework and metal-to-ligand charge transfer (MLCT) in the SDA. Additionally, the crystal exhibits thermally deactivated charge transport behavior. Moreover, it demonstrates an ultralow thermal conductivity of approximately 0.23 W/m·K over a broad temperature range, making it an excellent candidate for both thermal management applications.