Top: Long wave UV illumination. Bottom: Ambient illumination.
Solutions are in order of increasing particle size (longer growth time).
Bottom: Samsung flexible screen mobile phone flexibility test - GIF video source
Quantum dots - now in your phone
2013 was a big year for quantum dots with the first consumer products released using them in screens including some models of Sony Bravia TVs, and the Amazon Kindle Fire HDX 7. Mobile phones including the iPhone 6 are expected to include them in 2014. This is partly because of their improved energy efficiency, but also because they have the ability to be used in flexible and/or curved screens:
Curved (concave) screens are a major and very important new display technology innovation because they substantially improve display performance by significantly reducing and sometimes eliminating reflections from ambient light sources that washout the on-screen images. That also allows the displays to run at lower brightness, which increases the power efficiency and battery running time for mobile devices.
But what are quantum dots?
Simplifying things greatly, quantum dots are incredibly small particles. They range between 2 to 10 nanometers in diameter, which is equivalent to 50 atoms. The colour light that a quantum dot emits is directly related to its size; smaller dots appear blue, larger ones more red. In LCD screens they’re applied as a way of eliminating the need for White LED backlights and colour filters.
As Dr. Raymond M. Soneira, President of DisplayMate,
: “Instead of using existing White LEDs (which have yellow phosphors) that produce a broad light spectrum that makes it hard to efficiently produce saturated colors, Quantum Dots directly convert the light from Blue LEDs into highly saturated narrow band primary colors for LCDs.”
Not only do they have great energy efficiency as colour screens, but they also have applications in solar cells capturing photons and releasing current.