Researchers at Japan’s National Institute of Advanced Industrial Science and Technology (AIST) say that coffee compounds can increase current flow in semiconductor components by up to 100 times. Specifically, a thin layer of caffeic acid on the surface of the electrode helped significantly improve the current flow through the organic semiconductor device.
The science behind this amazing improvement in current flow is explained as follows. AIST BlogReports on studies conducted at the Tsukuba facility show that the action of caffeic acid on the electrodes causes the molecules on the surface of the component to spontaneously align, reducing resistance to current flow. Therefore, the current flow is multiplied by 100.
The discovery will help develop future organic semiconductor devices such as organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs), the scientists say. The discovery has been argued to be of particular value in promoting sustainability. By applying a thin layer of caffeic acid derived from plants, the use of unfriendly or unsustainable chemical resources can be reduced or avoided.
Currently, organic semiconductor manufacturers are using environmentally problematic materials for the role of electrode modification layers. One option for this layer, a polymer called Pedot:PSS, raises environmental pollution concerns. Alternative molybdenum trioxide materials use oxides of rare metal elements.
AIST researchers conducted tests using caffeic acid and various electrode materials, including gold, silver, copper, iron, indium tin oxide (ITO), and silicon with a native oxide layer. It can be seen graphically that the work function of the electrode increased by as much as 0.5 eV after caffeic acid treatment. According to the researchers, thin films of caffeic acid are very suitable for this purpose because they are insoluble in the organic solvents used in the manufacture of organic semiconductor thin films.
So far so good, what next? AIST researchers hope to apply this electrode modification/coating technique to organic semiconductor devices such as his aforementioned OLEDs and OPVs. The ultimate goal is to fully sustainably manufacture semiconductor components and IoT devices and facilitate their recycling.