Layered organic-inorganic hybrid materials based on ionic liquid and lead chloride: Insights into the structure and properties

Layered organic-inorganic hybrid materials are an emerging class of materials with excellent stability and outstanding optoelectronic properties. Here, we report the synthesis, characterization and optical properties of hybrid materials formed from lead chloride (PbCl2)-methylimidazolium chloride (MimCl) and PbCl2-alkyl methylimidazolium chlorides (AmimCl) of varying alkyl chain lengths viz. ethyl (C2mimCl), butyl (C4mimCl) and hexyl (C6mimCl). The molar ratio of PbCl2 to MimCl and AmimCl had a profound influence on the formation and properties of two-dimensional (2D) hybrid materials. The conformations and structural aspects of the synthesized materials with varying substitutions were extensively evaluated and correlated using computational studies. MimCl-PbCl2, C2mimCl-PbCl2 and C6mimCl-PbCl2 forms 2D structures while C4mimCl-PbCl2 was forming 2D and 1D structures as evident from topography and morphological evaluations through atomic force microscopy (AFM) and transmission electron microscopy (TEM). The materials synthesized were non-hygroscopic and exhibited excellent thermal stability. The AmimCl-PbCl2 shows absorption in the UV region with the onset extends to the visible range and exhibits good photoluminescence at 532 nm. These hybrid materials showed a charge carrier lifetimes (10–40 ns) and a photoresponse (photocurrent of the order microamperes) which make them a potential candidate for optoelectronic devices. •A new series of imidazolium-based ionic liquids-lead chloride compounds with 2D structures•Experimental methods and theoretical calculations confirm the 2D structure•This organic-inorganic hybrid material is non-hygroscopic and thermally very stable•A potential candidate as light absorber material for optoelectronic applications