Photodetectors — also known as photosensors — contribute to the convenience of modern life. They convert light energy into electrical signals to complete tasks such as opening automatic sliding doors and automatically adjusting a cellphone’s screen brightness in different lighting conditions. Researchers are advancing photodetectors’ use by integrating the technology with durable Gorilla glass, the material used for smartphone screens that is manufactured by Corning Incorporated.
Manufacturing and scaling photodetectors on glass must be done using relatively low temperatures (the glass degrades at high temperatures) and must ensure the photodetector can operate on glass using minimal energy. To overcome the first challenge, the researchers determined that the chemical compound molybdenum disulfide was the best material to use as a coating on the glass.
The team used a chemical reactor at 600 °C — a low enough temperature so as not to degrade the Gorilla glass — to fuse together the compound and glass. The next step was to turn the glass and coating into a photodetector by patterning it using a conventional electron beam lithography tool. The team tested the glass using green LED lighting, which mimics a more natural lighting source, unlike laser lighting that is commonly used in similar optoelectronics research.
The ultra-thin body of the molybdenum disulfide photodetectors allows for better electrostatic control and ensures it can operate with low power — a critical need for the smart glass technology of the future. The photodetectors need to work in resource-constrained or inaccessible locations that by nature do not have access to sources of unrestricted electricity. Therefore, they need to rely on pre-storing their own energy in the form of wind or solar energy.
If developed commercially, smart glass could lead to technology advances in wide-ranging sectors of industry including manufacturing, civil infrastructure, energy, healthcare, transportation, and aerospace engineering. The technology could be applied in biomedical imaging, security surveillance, environmental sensing, optical communication, night vision, motion detection, and collision avoidance systems for autonomous vehicles and robots. Smart glass on car windshields could adapt to oncoming high-beam headlights when driving at night by automatically shifting its opacity using the technology.