Charge Generation Ability of C60/CuPc Organic Heterojunction Connector Layer

Organic heterojunction connector(OHC) layers were widely used in tandem organic light emitting diodes(OLEDs) for their good light transmittance and technological compatibility with OLEDs. In a tandem OLED, the OHC layers, serving as the charge generation layer, played an important role in tandem OLEDs to function efficiently. In order to obtain the OHC layers with best performance, the devices with the structure of glass/ITO/tris(8-hydroxyquinoline) aluminum (Alq3)(60 nm)/C60(x nm)/CuPc(y nm)/N, N'-bis(naphthalen-1-yl)-N, N'-bis(phenyl)-be-nzidine (NPB)(40 nm)/Al(100 nm) were fabricated. The current density-voltage characteristic of the fabricated devices revealed that the OHC layer with the structure of C60/CuPc can generate charge carriers effectively, and show the largest charge carrier generation ability with the structure of C60(30 nm)/CuPc(10 nm). The forming physical mechanism of optimized OHC layer was reasonably explained. The results obtained in this paper can present an in-depth understanding of the working mechanism of tandem OLED and help ones fabricate high efficiency OLED. © 2019, Science Press. All right reserved.