A research team of Energy Science and Engineering at DGIST has come up with a technology to create environmentally friendly water-borne semiconductor inks using surfactants which are additives that combine substances of diverse properties and a component of soap.
Polymer semiconductors are carbon compounds displaying the electrical properties of semiconductors. It has been showcased as a next-generation material of wearable smart devices, etc. not only because they are light in weight and flexible, but also they can be processed in a broad area at low cost through the solution process. However, there is a problem that it causes substantial environmental pollution as toxic organic solvents are employed in the process.
In spite of the limitations, the research team has formed a semiconductor surface control method using surfactants for environmentally friendly semiconductor manufacturing processes that do not use harmful organic solvents and has created water-borne semiconductor inks.
The recently developed waterborne semiconductor ink by the research team contains small colloidal particles and less surfactant micelles compared to the waterborne semiconductor inks in the earlier studies. Consequently, it has a comparatively flat surface than the conventional waterborne semiconductor inks. The white and black image in the figure illustrates the comparison of the surface of the thin film made with the waterborne semiconductor ink created in this research and conventional one.
According to the research team, the method is projected to be applied in a range of electronic devices such as N-type and P-type transistors as well as complementary inverters, PN diodes, photodiodes as superior-quality thin films.
This research has fundamentally solved the environmental pollution problem generated during the production of organic semiconductor, which is spotlighted as the core material of wearable electronic devices. We have developed a source technology that can disperse various semiconductor materials into water through the simple chemical modification. We expect that it can be used in various optoelectronic devices ranging from transistors to solar cell, composite circuit, and image sensor.
Professor Dae Sung Chung, The Department of Energy, Science and Engineering