Next-generation LEDs could replace platinum, iridium with birch leaves

November 30, 2023

In an article published in the magazine Green chemistry, the scientists explain that the synthesis process is simple: They picked birch leaves on the Umeå campus and cooked them in a pressure cooker. This resulted in “carbon dots” about two nanometers in size that, when dissolved in ethanol, emit a narrow-band, deep-red light. Some of the optical properties of these birch leaf carbon dots are comparable to commercial quantum dots currently used in semiconductor materials, but unlike these do not contain heavy metals or critical raw materials.

“It is important to note that our method is not limited to birch leaves,” Jia Wang, co-author of the study, said in a media statement. “We tested different plant leaves using the same pressure cooking method and all produced similar red-emitting carbon dots. This versatility suggests that the transformation process can be used in different places.”

Using the carbon dots in a light-emitting electrochemical cell device, the researchers were able to show that the brightness produced was 100 cd/m2, which is comparable to the light intensity of a computer screen.

“This result shows that the transition from the depletion of petroleum compounds to the regeneration of biomass as a raw material for organic semiconductors is possible,” said Wang.

For the researcher, the carbon dots have broader potential than just light-emitting devices.

“Carbon dots hold promise for various applications, from bioimaging and sensing to anti-counterfeiting. We are open to collaborations and would like to explore further exciting uses for these emitting and sustainable carbon dots,” said the scientist.