OLEDs are the latest and most promising buzzwords in display technology. To give you an idea of their potential, imagine a cardboard-thin TV screen. Now imagine that you can roll up your TV, put it away or carry it wherever you go. Automatically, you start appreciating why millions, if not billions, of dollars are being poured into OLED research every year.

The aforementioned scenario is not hypothetical, or an imaginative scene from a Sci-Fi novel, as it exists right this minute at Ritek in Korea.

Now that you have begun to appreciate just how amazing OLEDs can be, let’s take a peak behind the scenes and see just how OLEDs work.

As the title states, OLED stands for Organic Light Emitting Diode – a diode is the simplest form of a semiconductor that allows current to flow in one direction and blocks it if it from flowing the opposite way.

Before we understand just how light is emitted by a diode, we need to understand the whole working process of a semiconductor.

Flow of Electricity:
Current flows from cathode to anode, or from negative charge to positive charge constantly. Elements get their charge depending on whether they have an extra electron or an extra proton. If they have an extra electron, they are negatively charged and emitted from the cathode. If they have more protons then they are positively charged and emitted from the anode.

When the electrons move from cathode to anode, we can say that the current is flowing. In insulators, all electrons are bonded to all protons, and hence there are no free electrons left to conduct the charge.

Doping:
Getting back to our semiconductor, it’s basically a substance that conducts electricity partially. The obvious question is how do you make a substance do something partially? The process is quite simple. What happens is that manufacturers take an insulator and add certain elements with free electrons to transform it into a partial conductor, or otherwise known as a semiconductor. This process is called doping.

Since we need free electrons to conduct electricity, we can do so by one of two ways:

1. We can add certain elements and turn it into a semiconductor; because the substance has a higher number of negatively charged particles, it is called an N-type semiconductor.
2. The second method is to extract a number of electrons from the substance to ultimately leave free protons. This will attract electrons from elsewhere, and therefore act as an anode. Since the element has more positive particles than negative ones, it’s known as the P-type semiconductor.

Next