Yellow tungsten oxide electrochromic film can be used to prepare a large area electrochromic device, which is a well known energy-saving glass for applying in building glasses. And the performance of the prepared electrochromic device must be tested. For example, test the coloring efficiency - one of the most important performance indicators for measuring electrochromic devices.
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So what is coloring efficiency? The coloring efficiency refers to a change in the optical density of the unit charge density injected into the electrochromic device during the coloring process at a specific wavelength.
According to Beer-Lambert's law, the change in absorbance of the electrochromic device ?A (i.e., the change in optical density, ?OD) is related to the charge (Q/A) injected per unit area: ?A=?OD= Log(Tb/Tc)=?Q/A
Wherein, ? is the coloring efficiency of the electrochromic device, and Tb and Tc refer to the transmittance of the electrochromic device at a specific wavelength in the bleached state and the colored state, respectively. The coloring efficiency ? and the change value of the optical density ?OD of the electrochromic device and the injected charge density Q/A have the following relationship: ?=?OD/(Q/A)
