Handheld devices have developed at a rapid pace since the noughties inception of the smartphone movement.  Technological progression has increased functionality and form factor with the trend leaning towards thinner and wider profiles.  

Researchers at the City University of Hong Kong and mainland China have developed a new screen that may lead to a new-generation of smartphones where the colour display and battery are one and the same.  This is due to the addition of a colour filter capacity to the battery by way of reinventing the structure and components of the traditional cell.

A standard cell creates an electrical current by forcing electrons along a wire connecting the cathode and anode poles.  The electrolyte between the two poles allows for the transfer of electrical charge and provides a medium for the chemical reactions that produce electrons, resulting in the energy change from chemical to electrical.  This structure is usually closed off with no other functionality but the new structure allows for the addition of a light filter. 

The researchers have created a new flat battery structure using ‘interlocking combs’ where cathode and anode poles in a comb-like structure are stuck together with their teeth fitting in between.  They then used a gel based electrolyte that prevented electrons escaping the anode poles to the nearby cathode combs as well as maintaining a new flat structure, required for its use as a screen. 

The big addition is then particles called quantum dots, in this case cadmium tellurium.  These particles will glow under certain light conditions, mainly UV, and are able to be placed in the electrolyte gel without interfering with the principle function of the battery.  Smaller quantum dots will glow red whilst larger will glow green.  Ingeniously the final colour required for a full colour display, blue, is produced by the new electrolyte, when under UV light. 

This technology is in its infancy but it has the potential to replace the LCD screens used in the majority of smartphones today.  Chemistry applicants could research the chemical processes taking place in liquid crystal displays and consider how they differ to this and other new screen technologies.

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