New SUHD TV from Samsung. What is Quantum Dot Technology?

Samsung SUHD Quantum Dot TV by the numbers

Samsung has presented the first SUHD TV with the best picture quality ever produced for an LCD-based television. Next level of the picture quality is achieved thanks to quantum dot nano crystal semiconductor technology which allows to create displays with more colors than standard LCD displays.

As a result of implementing the new technology, the TV picture becomes brighter, colors have better accuracy and higher saturation. Samsung says its SUHD sets achieve up to 2.5 times the light output of standard LED LCDs.

So what is the difference between a usual LCD TV and SUHD TV? And how does quantum dot nano crystal technology work?