Scientists from the chemistry department of the Adam Mickiewicz University in Poznań created the first proton LED in the world. The uniqueness of the discovery is provided by the fact that the diode operates in an aqueous environment, and shines thanks to the flow of protons.

The proton LED is a full analogue of a traditional electron diode with a p-n connector, where H + protons play the role of electrons, and hydroxyl groups – OH. The active material in which the process of charge recombination (H + and –OH) occurs and light emission is water (“proton semiconductor”) – explains the head of the team of scientists, Prof. Jerzy Langner.

The mechanical stability of the system is ensured by polymers, which are also carriers of functional groups (acid and basic), which allows the formation of a proton p-n junction on the border of the acid and alkaline zone. Applying voltage in the direction of the junction (“plus” on the acid side) causes a proton current to flow and light is emitted from the p-n junction area.