![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwOh2vaawd3jyMRDYK_pXXKVfaWW6HvgVkPMJDHJ4Sq3IAx-6F6K2aBEwTBkokLZ5btUlGCBeBW8C3fygfeqcx_G50FZ2g_YLnpFys4Pc4LXKeGUbCjW42i0RCyW5oXwgTcYRWag/s320/liquid_crystal_TakashiKATO2011.jpg)
Etched on a photoluminescent display, these liquid crystal Ginkgo leaves can shift through a trio of autumn colours under the glow of UV light.
Previously, displays made from a single luminescent organic or organometallic compound could only switch between two colour states. Now
Takashi Kato and Yoshimitsu Sagara of the University of Tokyo have developed a reversible display that glows red-orange, green or yellow in response to temperature and mechanical force.
The display consists of a mixture of two compounds, one of which harbours a fluorescent centre. When the mixture is heated to 146°C and then cooled to room temperature, it forms the red-orange state. A summer green appears after heating the red-orange colour state to 90°C, applying mechanical shear with a spatula, and then cooling it back to room temperature. Either the red-orange or green states can revert to yellow by shearing the mixture at room temperature.
The findings could be used to develop more cost effective multicolour displays.
Journal reference: Angewandte Chemie, DOI: 10.1002/anie.201100914.Image: Takashi Kato.
Article from: NewScientist Aug.5, 2011