Thermochromic Thin Films and Nanocomposites for Smart Glazing

Abstract

Solid-state thermochromic materials undergo semiconductor to metal transitions at a critical temperature, Γ. This chapter begins by describing the phenomenon of thermochromism, whereby the optical properties of a material change reversibly as a result of a change in temperature. The different types of thermochromism will be introduced with a focus on the thermochromism exhibited by solid-state materials. Also presented are the fundamental chemical principles that describe the electronic structure and properties of solids, and the chronological developments in the theory behind the thermochromic transitions that lead to the discovery of the semiconductor-to-metal transition. The focus is on vanadium dioxide, V0 2 , because its critical temperature is closest to room temperature, so it is a valuable material for potential application in thermochromic glazing. The possibility of fine-tuning this transition temperature involves introducing various dopants into the V0 2 lattice, which can increase or decrease Γ.Additionally, the chapter will examine the effects of dopants and the requirements of dopants to achieve the desired effect on T will be discussed. Solid-state thermochromic materials may be exploited in devices such as microelectronics, data storage, or intelligent architectural glazing, thus are required to be synthesis as thin films for use in such applications. The numerous synthetic techniques for making metal oxide thermochromic thin films will be investigated through a comparison of each synthetic method.In exploring recent research on the production of thin film, the chapter explains that micro-structural changes bought about by careful control of film growth conditions, and/or the use of surfactant, lead to an

Ionic Liquids–Cobalt(II) Thermochromic Complexes: How the Structure Tunability Affects “Self-Contained” Systems

“…In the solid matrix, a hysteresis effect of color transition may be affected by the nature of the matrix. In this context, thermochromic substances, embedded in coatings, are beginning to surface in the design of new materials for energy saving. − In some cases, the percentage of energy savings reached to more than 16% . Looking specifically at thermochromic transition-metal complexes, the states with different coordination numbers are shown to be in equilibrium with the ligand or solvent molecules where the increase in temperature generally favors the lower-coordinated complex …”