Morphological evolution of MnO2 based nanostructures by tuning the reaction time

The present paper illustrates a morphological evolution of Manganese dioxide (MnO2) nanostructures by varying the reaction time of hydrothermal process. To establish the morphological evolution, three samples were synthesized for three different reaction times (3 hrs, 5 hrs, and 7 hrs). Morphological characterizations of the synthesized nanostructures were performed using FESEM. Further, Raman spectra are presented to validate the crystal structure of the different nanostructures. It is evident from the FESEM images that microsphere/nanosheets based hierarchical structures, nanosheets intertwined with nanorods, and, nanorods based urchin like nanostructures were obtained by tuning the hydrothermal reaction time to 3 hrs, 5 hrs, and 7 hrs, respectively. The underlying morphological evolution mechanism is discussed and correlated with the characterization results. Moreover, three planar devices (based on microsphere/ nanosheets based hierarchical structures, nanosheets intertwined with nanorods, and nanorods based urchin like nanostructures) were fabricated by taking electrical contacts from top of the nanostructure layer and subsequently the device resistances were measured. Further, the electrical characterization finding is correlated with the material characterization results of the synthesized nanostructures for the three samples.