Investigation of microstructural changes in low dimensional nanomaterials using in situ transmission electron microscopy

Abstract

Low dimensional nanomaterials play a vital role in shaping a sustainable future by efficiently harnessing natural resources and converting energy. The achievement of precise fabrication and tailoring for optimal functionality across various applications is crucial. However, a comprehensive understanding of the intricate relationships between the structures, unique properties, and functions of these materials remains incomplete, requiring further exploration to establish fundamental parameters conclusively. Recent advancements in transmission electron microscopy (TEM) position it as a pivotal tool for characterizing low-dimensional nanomaterials at the atomic scale, providing direct insights into microstructures from the nanometer to atomic scale. Despite these advancements, technical constraints confine conventional TEM to operate in a vacuum and at ambient temperature, limiting observations to initial and final material states and leaving intermediate stages unexplored, potentially leading to misinterpretations. To address this gap, adopting advanced in situ methodologies is imperative. In situ TEM observations offer an unfiltered view of structural and chemical transformations during synthesis or operational phases when nanomaterials are exposed to external stimuli. In this dissertation, in situ TEM experiments were employed for real time observations of nanomaterial processes, encompassing dynamic events such as phase transformation, sublimation, and atomic damage. Through the utilization of heating holders and electron beam irradiation, in situ TEM facilitates the observation of low dimensional nanomaterials at the atomic level, offering valuable insights into their intricate behavior.