Combinatorial fabrication and study of white organic light-emitting devices based on non-doping ultrathin 5,6,11,12-tetraphenylnaphthcene (rubrene) yellow-emitting layer

Abstract

Non-doping white organic light-emitting devices (WOLEDs) based on an ultrathin yellow-emitting layer of rubrene inserted between the blue-emitting layer 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi) and the electron transport layer tris-(8-hydroxyquinoline)aluminum (Alq₃) fabricated by combinatorial sliding shutter technique are reported. Three of the the sixteen devices made had Commission Internationale de l'Eclairage (CIE) coordinates within the white region at 8 - 16 V, ranging from (0.31, 0.38) to (0.34, 0.42). All three devices had a 5-nm thickness of DPVBi layer and an ultrathin rubrene layer of thickness of 0.05-, 0.10-, and 0.15 nm, respectively. A maximum luminance of 12,900 cd/m² at 17 V and an efficiency of 5.5 cd/A at 8.5 V were obtained in the devices with 0.05 nm rubrene layer. These devices can be fabricated rather easily due to their simple device structure and they are very appealing to low-cost general lighting applications.