Context: Quantum dots (QD) are semiconductor nanocrystals that possess unique optical properties. Their emission color can be tuned from the visible throughout the infrared spectrum. This allows quantum dot LEDs to create almost any color on the CIE diagram. This provides more color options and better color rendering than white LEDs since the emission spectrum is much narrower, characteristic of quantum confined states. There are two types of schemes for QD excitation. One uses photo excitation with a primary light source LED (typically blue or UV LEDs are used). The other is direct electrical excitation first demonstrated by Alivisatos et al.

Question: What nanocrystals possess unique optical properties?
Answer: Quantum dots

Question: Quantum Dot LEDs can do what special skill?
Answer: create almost any color on the CIE diagram

Question: The narrowing of the emission spectrum in Quantum Dot LEDs allows them to do what?
Answer: better color rendering

Question: How many types of schemes are there in Quantum Dot LED excitation?
Answer: two

Question:  What non-nanocrystals possess unique optical properties?
Answer: Unanswerable

Question:  Quantum Dot LEDs don't do what special skill?
Answer: Unanswerable

Question: The narrowing of the emission spectrum in Quantum Dot LEDs disallows them to do what?
Answer: Unanswerable

Question: How many types of schemes are there in non-Quantum Dot LED excitation?
Answer: Unanswerable