Magneto-Conductance in Tri-(8-Hydroxyquinoline) Aluminum-Based Organic Light Emitting Diodes
XU Kai1,2, YANG De-Zhi1, MA Dong-Ge1**
1State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 2Graduate University of the Chinese Academy of Sciences, Beijing 100049
Abstract:The origin of magneto-conductance (MC) in tri-(8-hydroxyquinoline)-aluminum (Alq3)-based organic light emitting diodes is investigated. Our results clearly show that the generated MC is related to the singlet polaron pair dissociation. Further studies on the MC in an electron blocking layer N,N'-bis(lnaphthyl)-N,N'-diphenyl-l,l'-biphentl-4,4'-diamine (NPB) and a hole blocking layer 2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole (TPBi)-based devices indicate that the holes reaching the cathode from the dissociation of singlet polaron pairs on Alq3 are the main cause of the MC generation. It is found that the MC can be significantly reduced by doping a red fluorescence dye DCJTB as a hole trapper in Alq3.