Improvement of device performance by co-doping of an emitting dopant with hole-and electron-transport materials

摘要

We demonstrated that the efficiency of green organic light-emitting diodes (OLEDs) was improved by co-doping with hole transport material, N '-bis-(l-naphyl)-N,N '- dipheny 1-1,1'-biphenyl-4,4'-diamine (NPB) and electron transport material, bis(2-methyl-8-quninolinato)-4-phenylphenolate aluminum (BAlq), into emitting layer. Co-doping with NPB and BAlq can improve charge balance which makes it possible to enhance device efficiency. The maximum luminous and quantum efficiency of BDAT-P doped device was measured to be 5.56 cd/A and 1.99 %, respectively. Device co-doped with NPB, BAlq and BDAT-P resulted in the most efficient device, in which maximum luminous and quantum efficiency were 8.36 cd/A and 3.19%, respectively.