Cameras, light barriers, and movement sensors all work with light sensors that are already found in many applications. In the future, these sensors might also play an important role in telecommunications, as they enable data transmission via light. Printable light sensors have been developed that can see colors.
New technologies will increase the demand for optical sensors for a variety of applications including visible light communication (VLC) that uses interior lighting of buildings for optical communication. In terms of security, speed, and accessibility, this technology has a number of advantages over conventional transmission processes such as WLAN or Bluetooth. It combines the advantages of a special type of materials — organic semiconductors — and their production by printing processes.
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. Light intensity can be measured as 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 researchers found a composition of materials suited for use as wavelength-sensitive light detectors 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.
Printing of semiconductor components is a relatively young process but has a considerable potential for future applications. 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. 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, as the demand for sensors is increasing in the Internet of Things, in smart cities, and in Industry 4.0.