Quantum Dot Heat Engine
What are heat engines? QD heat engines will revolutionize thermoelectric power due to their high efficiency as compared to standard heat engines. Amazingly, the quantum dot heat engine produces as much energy per square meter as sunlight on the Earth.
How it Works:
The image to the left depicts a cross section of the "Swiss Cheese Sandwich" thermoelectric generator, which facilitates the movement of electrons. The cold bottom layer is beneath a layer of QDs. This is covered by a hot central semiconductor. A fourth layer covers this with a different layer of QDs, and finally the fifth layer is a cold electrode.
Pictured in the center is the energy level diagram of the quantum dot heat engine. Below is a fish ladder analogy to simplify how this works.
In the figure to the right, the red arrows represent heat flow directed towards the central layer of the quantum dot heat engine. The blue arrows represent the flow of electrons through the engine. The yellow-green layer represents the resonant QD semiconductor material "swiss cheese" in between the hot and cold conductive plates. Unlike other thermoelectric engines, the quantum dot heat engine is unique in that the hot material is central, surrounded by two cold ends.
Pictured in the center is the energy level diagram of the quantum dot heat engine. Below is a fish ladder analogy to simplify how this works.
In the figure to the right, the red arrows represent heat flow directed towards the central layer of the quantum dot heat engine. The blue arrows represent the flow of electrons through the engine. The yellow-green layer represents the resonant QD semiconductor material "swiss cheese" in between the hot and cold conductive plates. Unlike other thermoelectric engines, the quantum dot heat engine is unique in that the hot material is central, surrounded by two cold ends.
Fish Ladder Analogy:
Electrons traveling through the quantum dot heat engine resemble salmon swimming up a fish ladder. The bottom cold layer of the heat engine contains electrons with various energy levels (Fermi energy spread). Once these electrons reach a certain energy level, they “jump” (called resonant tunneling) from the cold to the hot layer. Here the electrons are facilitated by a layer of resonantly-tuned quantum dots, the same way that a fish ladder helps salmon swim upstream. After gaining kinetic energy in the hot central layer of the heat engine, the process is repeated as the electrons tunnel through a second quantum dot layer from the hot layer to the top cold layer. The electrons are stored in a capacitor which is discharged to power internal medical devices.