Researchers from the University of Toronto discovered that using chlorine can drastically reduce OLED device complexity and improve its efficiency. In fact in their tests, the efficiency more than doubled at very high brightness. The idea is to add a one-atom thick sheet of chlorine on the ITO electrode used in OLEDs. This can make the electrode a more efficient electrical transport - and so there's no need for a 'transport' layer as used in current designs.
The researchers developed a UV light assisted process to achieve chlorination (which negates the need for chlorine gas) - and so the whole process is easy to engineer, safe and reliable. The new OLED which used the CI-ITO electrode achieved a record efficiency of 50% at 10,000 cd/m2.