Advanced window technology has been identified as a component which can greatly reduce the energy consumption of the building envelope. The next generation of advanced windows will involve a "smart-coating" technology where the optical and solar properties can be dynamically controlled. The performance of such coating is ultimately linked to its materials properties such as chemical composition and microstructure. These properties are directly influenced by the deposition process conditions. A promising dynamic windows technology is based upon the electrochromism process. An electrochromic window system consists of a sandwich of multilayered thin films coated on glass. When a small bias is applied between the top and bottom electrodes, the optical properties and energy performance of the electrochromic and ion storage layer will be altered. In this presentation, I will present some results based on advanced material characterization on a tungsten based electrochromic device to understand its chemical composition. I will also discuss some of the latest research and development effort in the deposition of an important class of materials frequently used in window coating known as transparent conducting oxides.