Title : Color control of electrochromes by structural modification
Abstract:
Materials that can charge their color on-demand have been used in a wide range of applications. While most uses rely on the acuity of the materials in the visible region, the invisible changes occurring in the NIR offer environmental benefits. This is the case when the color changing materials are integrated into smart windows. By filtering NIR sunlight during light intense periods, the cooling loads of buildings can be reduced. This contrast with allowing radiant heat to enter buildings for heating during cool periods. Reversibly filtering the light that can pass through windows has the economic benefit of reducing the cooling/heating loads of buildings. Given the electricity that sustains building operations is often produced from environmental deleterious sources, reducing energy consumption for building cooling/heating also has ecological benefits.
Targeted properties of smart windows are: reversible colors change in both the visible and the NIR regions; consistent coloration/bleaching over extended cycles of color switching; and reversible oxidation/reduction. The effect of structural modification on the color switching materials will be presented. Of importance, the NIR absorption and the bleaching time contingent on the type of electronic groups on the molecular electrochromes will be discussed towards achieving the ideal color switching material. Properties of the materials assessed in solution and then in operating test devices will be presented towards achieving high performance smart windows.
