| Organic light emitting devices (OLED) based on small molecule materials capable of white light emission have been fabricated and electrical and optical performance of devices was characterized. The fabricated OLEDs utilize one hole transport material, N, N'-diphenyl-N, N'-bis(3-methylphenyl)-1, 1'-biphenyl-4, 4'-diamine [TPD], and three light emitting materials including 4, 4'-bis(2, 2'-diphenylvinyl)-1, 1'-biphenyl [DPVBi], Tris-(1-phenylisoquinolinato-N) iridium (III) [Ir(piq)3], and tris-(8-hydroxyquinoline) aluminium [Alq3] to achieve the color blending close to the white light. The overall OLED configuration is in a multi-layer stacking structure. A total of 6 different OLED layer thickness configurations were implemented to investigate the effect of the layer thickness parameters. In one particular configuration, the CIE color coordinates range from (0.357,0.358) at 140.4 cd/m2 to (0.303,0.360) at 1321.7 cd/m2, which indicates adequate color stability in the medium to high luminance range. The luminance value of 1321.7 cd/m2 at the current density of 64.9 mA/cm2 and the operating voltage of 14 V indicates that the device is capable of producing a relatively high level of brightness while operating at relatively low operating voltage and low driving current density. |
