Tech

The Paper That Could Print Images, Texts Using Light Discovered

Elaine Hannah
First Posted: Feb 06, 2017 03:50 AM EST

Printing cost is quite expensive especially when one has lots to duplicate. On the other hand, with the discovery of a paper that could print images and texts using light, the expenses could be cut significantly.

The paper is coated with a special nanoparticle and alters the color when the ultraviolet (UV) light shines on it and print. It is erased by heating to 120 degrees Celsius and could be rewritten for over 80 times.

This is developed by researchers at the University of California and Shandong University in China. The discovery was described in a recent issue of Nano Letters, according to Phys.org.

Yadong Yin, a Chemistry Professor at the University of California, Riverside, said that the greatest significance of their work is the development of a new class of solid-state photoreversible color-switching system to fabricate an ink-free light-printable rewritable paper that has the same feel and appearance as conventional paper. On the other hand, this can be printed and erased without the need for additional ink. He added that their work is believed to have enormous economic and environmental merits to modern society.

So, how does this kind of paper print using light? There are two types of nanoparticle that are combined for the creation of new coating. These involve a Prussian blue, which is a blue pigment used in paints that convert colorless when it gains electrons and the titanium dioxide (TiO2). This is a type of photocatalytic material that zooms chemical reactions when exposed to UV light. When the two substances are mixed, they are converted into a coating with solid blue color. Expose the paper to UV light and the TiO2 particles react and release electrons that convert the Prussian blue pigment colorless and prints the images or texts.

The printing stays on the page for at least five days and will gradually turn back to blue. The fading process can be hustled if heat is applied. The team said that it expects this technology to be cheaper when made on a commercial scale, according to Science Alert.

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