Semiconductor Nanocrystals tagged posts

Artist’s rendering of bioreactor (left) loaded with bacteria decorated with cadmium sulfide, light-absorbing nanocrystals (middle) to convert light, water and carbon dioxide into useful chemicals (right). Credit: Kelsey K. Sakimoto

Photosynthesis provides energy for the vast majority of life on Earth. But chlorophyll, the green pigment that plants use to harvest sunlight, is relatively inefficient. To enable humans to capture more of the sun’s energy than natural photosynthesis can, scientists have taught bacteria to cover themselves in tiny, highly efficient solar panels to produce useful compounds. “Rather than rely on inefficient chlorophyll to harvest sunlight, I’ve taught bacteria how to grow and cover their bodies with tiny semiconductor nanocrystals,” says Kelsey K. Sakimoto, Ph.D....

Illustration depicting semiconductor nanocrystal to molecule triplet energy transfer and established subsequent reactions. Credit: Image generated by Dr. Cedric Mongin

It extends the lifetime of originally prepared excited state by 6 orders of magnitude. This has implications for solar energy conversion to photochemical synthesis to optoelectronics to light therapy for cancer Rx. Excitons are the electron/hole pairs formed in semiconductor nanocrystals upon absorption of light, temporarily storing it as chemical energy. In solar cells, for example, excitons transport energy through the material so that it can be collected and converted into electricity.

In terms of photochemistry, the major drawback to using most semiconductor nanocrystals as photosensitizers lies in their short excited st...