| 초록 |
To increase the efficiency of the organic EL devices, devices with LiF/Ca cathode and those with Ca:LiF composite cathode have been fabricated. In both cases, the lowering of the operating voltage and the increase in luminance are observed. This has led to the increase of power and emission efficiency. For devices with LiF/Ca cathode, the optimum thickness of the LiF layer has been found to be about 0.7 nm. As the thickness of the LiF layer increases up to 0.7 nm, the efficiency of the device is enhanced. But beyond this optimum thickness, the efficiency is deteriorated. The devices with Ca:LiF composite cathode has shown similar enhancement in I-V characteristics and efficiency. For devices with Ca:LiF composite cathode, the optimum value of LiF/Ca ratio and thickness have been determined to be 2 % and 300 nm, respectively. |
