Caffeic acid in semiconductors: faster and more efficient

Caffeic acid, a naturally occurring ingredient in coffee, could make semiconductors work faster . This according to research by the Japanese Institute of Advanced Industrial Science and Technology (AIST). In fact, a thin film of caffeic acid on the electrode surface of an organic semiconductor would improve current flow as much as 100 times . The substance causes the molecules to align on the surface of the organic semiconductor, thus reducing the resistance to flow. But how did the researchers manage to achieve such a result and what does it mean for the world of technology?

The problem of the environmental impact of semiconductors and other substances used in combination with acid

Currently, organic semiconductor manufacturers use environmentally problematic materials to implement electrode modification layers. In fact, one of the polymers used, called Pedot:PSS, raises concerns about environmental pollution. Unfortunately as an alternative, a molybdenum trioxide material, uses a scarce metallic element oxide.

caffeic acid

The researchers conducted tests using the acid in question and a variety of electrode materials; these include gold, silver, copper, iron, indium tin oxide (ITO), and silicon with a native oxide layer .
Their graphs show that the work function of the electrode increased by as much as 0.5 eV (electron volt) after treatment with caffeic acid. In addition, the caffeic acid thin film does not dissolve in the organic solvents typically used in the production of organic semiconductor thin films .

The process behind the operation and the consequences of the application of caffeic acid in semiconductors

The AIST scientists observed that the action of caffeic acid on the electrode causes the molecules to spontaneously align on the surface of the component . This is by reducing the resistance to current flow and achieving the 100-fold increase in current flow.

The hope of the researchers is that the discovery will be particularly valuable for promoting sustainability. In fact, caffeic acid is so called because it was originally found in coffee extracts; later scholars also found it in many foods of vegetable origin, in plants, and in nature in general. Through its use they hope to reduce or avoid the use of chemical resources harmful to the environment or unsustainable.

Through its use it will be possible to develop future organic semiconductor devices. Some examples of these are organic light emitting diodes (OLEDs) and organic solar cells (OPVs).

Caffeic acid, a component that "seems" unusual for use in electronics

To better understand the singularity of the discovery and its relationship with the easy availability in nature it is better to make some clarifications. First of all we must clarify that it has no correlation with caffeine and we must not be fooled by the name. Although scientists have found its presence in coffee drinks, as reported earlier, it is very abundant in nature.

caffeic acid
Eucalyptus branch

For example, plants that contain it are Eucalyptus globulus (in the bark), the barley grain Hordeum vulgare and the grass Dipsacus asperoides . Or in the freshwater fern Salvinia molesta , or again, it is one of the components of olive and Argan oil. It is found in relatively high levels in herbs of the mint family, especially thyme, sage and spearmint. Other foods where it can be found are spices, such as Ceylon cinnamon and star anise. But still, it is also present in moderate levels in sunflower seeds, applesauce, apricots and prunes.

The list goes on and it makes us understand how important the implications of its use are in an area so full of requests for materials. Semiconductors are the building blocks of all major electronic devices such as transistors, diodes and others. With the advent of consumer electronics, these have undergone a strong surge in production. But at the same time they have also caused great concern for disposal and environmental impact . We therefore welcome solutions that can lead to an (at least initial and partial) improvement of these conditions. And in the meantime improve the performance of the devices themselves.

The article Caffeic acid in semiconductors: faster and more efficient was written on: Tech CuE | Close-up Engineering .