الفهرس Only 14 pages are availabe for public view
 |  | from | 134 |  |  |
| | | from | 134 | | |
Abstract
Research on quantum dot light emitting device (QDLED) has maderemarkable advances in just one decade. The external quantum efficiency hasimproved by over two orders of magnitude and highly saturated color emissionis now the norm. Although the device efficiencies are still more than an order of magnitude lower than those of the purely organic light emitting devices,there are potential advantages associated with quantum dot (QD)-based devices, such as a spectrally pure emission color, spectrally tunable by changing QD diameter such that we can access most of visible range with single material set, more stable and longer lifetimes, which will certainly merit future research. While semiconductor QDs have exhibited electroluminescence EL) emission with narrower bandwidth than that of many organic molecules, many of their potential applications, particularly in the fields of display, light emitting sources and bio/chemical sensing, require further reduction in
emission bandwidth in order to achieve display color purification and improved sensor resolution. A possible solution is to modify the EL emission properties of QDs by embedding them inside microcavity structures. The confinement applied by the microcavity will alter internally the optical mode density within it. Furthermore redistribute the emission output spatially and spectrally. The enhanced coupling between the excitons and the confined electromagnetic field will result in significant improvement in light output directionality and purification of colors. So microcavity devices have been attracted considerable attention due to their potential to achieve spectral narrowing, brightness enhancement, or multipeak emission from the same emitting layer. The research of quantum dot light emitting device (QDLED) is in two directions. Firstly, it involves a detailed examination and understanding of the processes and parameters important for device operation. The second direction is a comprehensive theoretical model of the QDLED which is required in order to understand the interplay of the various mechanisms in the device and to determine which the critical ones are. In addition, a comprehensive model