tuhin4u (Unstopable Lover + Mariana World DIAMOND member): An OLED display works without a backlight; thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions (such as a dark room), an OLED screen can achieve a higher contrast ratio than an LCD, regardless of whether the LCD uses cold cathode fluorescent lamps 0r an LED backlight. *05-10-14 - 04:55:35
tuhin4u (Unstopable Lover + Mariana World DIAMOND member): The first observations of electroluminescence in organic materials were in the early 1950s by André Bernanose and co-workers at the Nancy- Université in France. They applied high alternating voltages in air to materials such as acridine orange, either deposited on 0r dissolved in cellulose 0r cellophane thin films. *05-10-14 - 04:56:19
tuhin4u (Unstopable Lover + Mariana World DIAMOND member): The proposed mechanism was either direct excitation of the dye molecules 0r excitation of electrons. *05-10-14 - 04:57:16
tuhin4u (Unstopable Lover + Mariana World DIAMOND member): In 1960, Martin Pope and some of his co-workers at New York University developed ohmic dark-injecting electrode contacts to organic crystals. They further described the necessary energetic requirements ( work functions) for hole and electron injecting electrode contacts. These contacts are the basis of charge injection in all modern OLED devices. Pope's group also first observed direct current (DC) electroluminescence under vacuum on a single pure crystal of anthracene and on anthracene crystals doped with tetracene in 1963 using a small area silver electrode at 400 volts. *05-10-14 - 04:59:04
tuhin4u (Unstopable Lover + Mariana World DIAMOND member): The proposed mechanism was field- accelerated electron excitation of molecular fluorescence. Pope's group reported in 1965 that in the absence of an external electric field, the electroluminescence in anthracene crystals is caused by the recombination of a thermalized electron and hole, and that the conducting level of anthracene is higher in energy than the exciton energy level. *05-10-14 - 05:00:58