Organic Light Emitting Diodes

Abstract

OLED'S are simple solid state devices that work on the principle of electro-luminescence. They comprise very thin films of organic compounds in the electro-luminescent layer. These organic compounds have a special property of creating light when electricity is applied to it. The organic compounds are designed to be in between electrodes. Out of these one of the electrodes should be transparent. The result is very bright and crispy display with power consumption lesser than usual LCD and LED. OLEDS emit light through a process called as electrophorescene every at  low operating voltages  through high efficiency .Like an LED,  an oled is solid state semiconductor   that device that is 100 to 500 nanometers thick or 200 times smaller than human hair. OLEDS can have either two layers or three layers of organic material. More the number of organic layers greater will be the efficiency. Like an lcd, the OLED does not require a backlight for its normal working. This makes them more advantageous in saving space and also weight. It also helps them in displaying deeper black levels than LCD's. Oled is also capable of making high contrast ratio when it is displayed in a dark room than LCD as well as LED. An oled mainly consists of cathode anode and a organic layers. Based on the arrangement of cathode and anode OLEDS are divided into two type's active and passive OLED.

OLEDs are used in small screen devices such as cell phones, PDAs and digital cameras. Research and development in the field of Oleds is proceeding rapidly now and may lead to future applications in heads- up displays, automotive dash boards etc.