A novel citric acid facilitated supramolecular Zinc(II)-metallogel: Toward semiconducting device applications

Abstract

A fascinating approach for the instantaneous synthesis of citric acid as a low molecular weight gelator and zinc ion based metallogel through one-shot mixing in N,N-dimethyl formamide medium has been achieved at room temperature under ambient condition. The rheological study was applied to investigate the mechanical property of the synthesized metallogel material. The layered structure of the metallogel was envisaged through FESEM and the present elements were characterized through EDX mapping investigations. The possible metallogel formation strategy has been analyzed through FT-IR and Raman spectroscopic study. Slight shifting of the X-ray diffraction peaks of the precursor components indicated the structural changes occurring during the gelation and the resulting layered structure. Thermogravimetric analysis (TGA) revealed the role of the fuel (here citric acid) used in the synthesis, and also indicated the formation of ZnO from citric acid. Differential scanning calorimetry (DSC) revealed a phase transition from gel to solution (gel-to-sol) indicating a dramatic change in viscosity during heating and the process is reversible. Optical band gap estimated from absorption characteristics of the gel which suggested a strong semiconducting nature for the material. The semiconducting nature of the metallogel has been further verified with electronic device characterization and charge career mobility evaluation. These results suggest that this gel has an impressive electron mobility value which may be the highest (by several orders) among the reported mobilities of metallogels.