Color-Tunable Triple-State Smart Window

Materials that rapidly change their optical properties in response to external stimuli are crucial for displays and smart window applications. Herein, a fluorescent red dye modified with liquid crystal (LC) side chains is described to be interactive with a LC host, resulting in a color-tunable triple-state smart window. The dye solubilizes in the LC matrix with increasing temperature, resulting in a red-colored, absorbing state, recovering transparency again by reaggregation of the dye within minutes upon cooling. This dye is used to fabricate a device that can be electrically switched from a red-colored, absorbing state to an intermediate scattering state and at greater electrical fields, a transparent state. Using a second dichroic fluorescent dye, heating the device transitions the window's color from yellow/green to red. The multiresponsive optical changes could find applications in many fields, including displays, smart windows, electricity generation, and signage.

Automated summary

A fluorescent red dye modified with liquid crystal side chains interacts with a LC host to create a color-tunable triple-state smart window. The dye solubilizes in the LC matrix with increasing temperature, resulting in a red-colored, absorbing state, recovering transparency upon cooling. This dye can be electrically switched from a red-colored, absorbing state to an intermediate scattering state and eventually to a transparent state, offering multiresponsive optical changes useful in various applications.