According to the source, the ink is based on titanium nanocrystals. Their interaction with ultraviolet darkens them, and oxidation with oxygen is eliminated.

Details of the invention

• According to the authors, the new inks are designed to reduce paper waste.
• The material is made of three non-toxic components.
• TiO semiconductor₂ It darkens when irradiated with ultraviolet light due to charge separation and reduction of titanium atoms.
• Oxygen in the air re-oxidizes the titanium, reversing the reaction.
• Seeing this perspective, the researchers decided to continue the blackening of TiO2.₂ and supports color change.
• They used urea nitrogen as the alloying impurity and added a non-toxic substance called diethylene glycol to the nanocrystals – it kept TiO₂ in the darkened state.
• The crystals were then applied to glass and paper to create a uniform coating on which ultraviolet radiation could be written.
• Now all it took to create the inscription was 30 seconds of UV exposure with a wavelength of less than 400 nanometers. Scientists emphasized that this does not require a powerful light source – significant range is important.
• After all managed to create a high-contrast pattern that only disappears when heated or oxidized.

During the experiments, the authors created patterns or printed text. They also recorded manually with a laser pen. Both options yielded a high contrast pattern that remained stable for hours. It just disappeared when heated or slowly faded due to oxidation. The team states that you can extend the life of the print by coating the surface of the film with a non-toxic polymer layer, which will protect the surface from oxygen.

In total, the new technology provides up to 50 cycles of recording and erasing without loss of contrast. It will be needed in areas where reusable surfaces are required or where information needs to be rewritten several times, such as transport tickets, coupons, and information boards.