• Researchers Develop Printable Organic Photodiodes       2020-03-30

    At the InnovationLab in Heidelberg, scientists of Karlsruhe Institute of Technology (KIT) have succeeded in developing printable light sensors that can distinguish wavelengths and, hence, enable data transmission by light. Dr. Gerardo Hernandez-Sosa of KIT’s Light Technology Institute, one of the authors commented that their research is based on the idea of combining the advantages of a special type of materials, namely, organic semiconductors, and their production by printing processes. New technologies will increase the demand for optical sensors for a variety of applications, including visible light communication (VLC). VLC uses the interior lighting of buildings for optical communication. In terms of security, speed, and accessibility, this technology has several advantages over conventional transmission processes, such as WLAN or Bluetooth. Semiconductors are the basis of computers, smartphones, solar cells, and many other technologies. Some of the semiconducting materials react to light by changing their conductivity. The light intensity can be measured as an electrical current. Using a printer, some materials can be applied to a carrier material like printing ink. These materials react to varying wavelengths, which means that they can distinguish colors. The team of Hernandez-Sosa has now succeeded in finding a composition of materials suited for use as a wavelength-sensitive light detector as well as for printing onto flexible carriers. Printing can be performed on very small to very large areas. The layout can be designed easily with the help of a computer. High numbers of these photodetectors of any design can be produced on flexible, light materials. Hence, they are particularly suited for mobile devices. The printing of semiconductor components is a relatively young process, but has considerable potential for future applications. The industry is already making large investments in the production of printed OLED displays for TVs and smartphones. Printed flexible solar cells or pressure sensors are commercially available already. Production of printed light detectors has also reached the industrial scale. It is therefore highly probable that these elements will be used in many applications in the future, even more so, as the demand for sensors is increasing in the internet of things, in smart cities, and Industry 4.0. Click here to read the full paper.