Behind every colour lies precise science – the arrangement of atoms, molecular bonds, light spectra – and it is precisely at this point, between molecules and colours, that materials science and new innovations develop. In anticipation of Researchers' Night, researchers at the Institute of Solid State Physics, University of Latvia (ISSP UL) share stories about the interaction of colour and science in our daily work and laboratory experiments.
Several species of octopus and squid can change their skin colour to blend into a patterned seafloor or ward off predators with menacing, vivid hues. These animals do so with such speed and precision that their skin can be compared to a sophisticated organic pixel display – this similarity is explained by Natālija Tetervenoka, a researcher at our Laboratory of Organic Materials.
Cephalopods achieve this using chromatophores – tiny, pigment-filled sacs expanded or contracted by muscles – and iridophores beneath them that reflect light. A direct neural pathway from the brain to the skin muscles allows them to instantly project dynamic patterns and colours; chromatophoresprovide the yellow, red, brown, or black pigment, while iridophores reflect blue, green, and silvery hues. “A flexible, bright and energy-efficient colour display? Sounds like something the world is striving for in the development of organic light-emitting diode (OLED) technology,” says Natālija.
“In our lab, we are investigating new materials that could be used for OLEDs, which are capable of changing colours almost instantly without moving parts. Instead of muscle contraction, we pass an electric current through a complex, multi-layered structure of organic materials. Electrons are injected into the sample, exciting the material and causing it to release energy in the form of photons of light within nanoseconds. By placing red, green, and blue organic subpixels side by side, OLED devices instantly adjust the relative brightness of the subpixels, creating an extremely fast and smooth colour change across the entire surface without any mechanical delay.
“Nature relies on biomechanics, while we use electroluminescence,” explains Natālija. “However, the ultimate vision in this field remains surprisingly aligned: the development of ultra-thin, flexible, and energy-efficient displays that seamlessly adapt to their environment.”
Discover more colourful scientific wonders in the article series Between Molecules and Colours!
