The quantum dots in TVs controversy goes to court, with a Chinese vendor saying it uses cadmium in sets

Soju caps might be popping in Seoul as Samsung's watching its Chinese TV competition getting hoist on its own petards over the on-going quantum dots issue.

You've probably seen quantum dots advertised, for QLED and similar TVs. They are tiny particles of semiconductor material, typically just a few nanometers in size (about 10,000 times smaller than the width of a human hair).

What makes them special is that they're so small that quantum physics effects come into play, changing how they interact with light and electricity - long story short, quantum dots is remarkable, Nobel Prize winning technology.

They're used in TVs, medical imaging, and even solar cells to capture the full spectrum of sunlight. Needless to say, if you got quantum dot tech as a manufacturer, you have a product that can be sold at a premium.

Now, the quantum dot issue seems to have blown up in the faces of Chinese TV makers. 

To be clear, there's a level of public relations "black opsing" from Samsung and Korean vendors going on here, and they're hardly unbiased observers but instead keen to draw the public's attention to the matter.

It's not a new issue either. The alleged lack of quantum dots in TVs from competing Chinese vendors TCL and Hisense emerged last year. America being a litigious nation, this month the matter of whether there are actually quantum dots in certain Chinese made TVs has gone to court.

For nearly two decades, the Korean electronics giant has been the world's largest TV maker. It's a safe bet that it wants to keep that position, in the face of withering onslaught from Chinese competitors.

Now, it could be that TCL has helped Samsung with that goal which is quite remarkable. To prove that it is in fact selling quantum dot TVs, the Chinese manufacturer commissioned a Swiss laboratory of repute to test the display panels it uses. It said the quantum dot ones in TCL sets contain at lest four micrograms of cadmium per kilogram.

Cadmium-selenide (CdSe) is a compound used to make quantum dots. The presence of CdSe in TCL TVs proves that they're QD film equipped - and that might be so, but it's not really going to help TCL et al as such, because cadmium is nasty stuff that's classified as a carcinogenic substance, and can cause kidney failure as well. 

Releasing independent test results that show the TVs sold contain cadmium, even in small quantities, is on the face of it, a monumentally terrible idea. 

In fairness, the cadmium issue isn't as straightforward as it may seem. As this 2015 The Conversation article on QLED technology sets out, if cadmium is used in TVs, it's firmly embedded in the panels and very unlikely to affect users. However, manufacturing of the sets and disposal of them is quite another thing and people could be exposed to the toxic substance then.

Even then, the fact that QLED TVs can be more energy efficient could lower the amount of cadmium entering the environment. Cadmium is produced by burning coal to generate electricity, so if less of that polluting activity is required, the lower the amount of the toxic heavy metal is released that way.

Either way, despite such nuances, the display tech industry is acutely aware that cadmium is bad news and should not be used if possible.

Samsung has been hard at work to rid its TVs of the carcinogenic substance for years. It wasn't an easy task, as this Samsung article on materials researcher Dr Eunjoo Jang suggests, but the Korean maker says it hasn't used CdSe in quantum dot displays since 2014.

Nowadays, TV makers are switching to indium phosphide (InP) quantum dots to replace cadmium, along with nitrogen doped carbon (NCD), as the material for the nanoparticles.