The Technology
Current IR sensors are based on small band gap materials require cryogenic cooling and usually have low quantum yield, hence are expensive and hard to use. Photonic crystals containing nano particles can transform IR radiation into visible light that is detectable by standard, highly efficient visible light detectors. Air stable core/shell quantum dots (QDs) that absorb between 950 nm – 1500 nm were synthesized. The QDs have high quantum efficiency and can be effectively coated by silica shell. The core is comprised of PbSe semiconductor with typical absorption in the near infrared spectral regime, and tunable upon a change of the QD’s size. An intermediate layer composed of CdSe is used for crystallographic matching with the ZnS shell. Hence, the ultimate QDs have the composition, PbSe/CdSe/ZnS composition. The exterior shells also add tunability to the band-gap energy, all engineered to achieve the desired absorption edge .The QDs are located in the photonic crystal very accurately in order to increase its emission efficiency.
Advantages
- Efficient and tunable IR sensors
- Stable sensors
- Low cost and simple manufacturing process
Applications and Opportunities
- IR sensors
- Photonic crystals