The Engineer – Moths’ eyes have inspired the development of nanoscale materials that could reduce radiation dosages received by patients being X-rayed and improve the resolution of the resulting images.
In lab experiments, Yi and colleagues found that adding the thin film to the scintillator of an X-ray mammographic unit increased the intensity of the emitted light by as much as 175 per cent compared with that produced using a traditional scintillator.
It consists of a 500nm thin film made of cerium-doped lutetium oxyorthosilicate. These crystals were encrusted with pyramid-shaped bumps or protuberances made of silicon nitride. Each protuberance, or corneal nipple, is modelled after the structures in a moth’s eye and is designed to extract more light from the film.
Between 100,000 and 200,000 of the protuberances fit within a 100 x 100μm square. The researchers then made the sidewalls of the device rougher, improving its ability to scatter light and enhance the efficiency of the scintillator.
Source: Optics Letters. (a) The self-assembly of SiO2 nanoparticles on the top of high index light extraction layer Si3N4, which is deposited on Lu2SiO5:Ce thin film. (b) The scanning electron microscope image of the improved bio-inspired moth-eye nanostructures with certain degree roughness on the sidewall, which shows interesting nano-on-nano features
Abstract We have utilized biologically inspired (bio-inspired), moth-eye nanostructures and further improved this biomimetic structure to enhance the scintillator materials external quantum efficiency significantly. As a proof of concept, we have demonstrated very high light output efficiency enhancement for Lu2SiO5:Ce3+ (LSO:Ce) film in large area, the X-ray mammographic instrument was employed to demonstrate the light output enhancement of the Lu2SiO5:Ce thin film with biologically inspired (bio-inspired) moth-eye-like nanophotonic structures. Our work could be extended to other thin film scintillator materials and is promising to achieve lower patient dose, higher resolution images of human organs and even smaller scale medical imaging.