Abstract
We reviewed white organic light-emitting diodes (WOLEDs) briefly in this paper and suggested the significance of a hole-blocking material for the fabrication of WOLEDs. And we studied the electroluminescence (EL) spectra of two kinds of WOLEDs using each different hole-blocking material. The WOLED with blue-emitting aluminum quinoline (BAlq) had a broad EL spectrum. The broad spectra were caused by overlapping three emissions of 3 kinds of emission materials due to wide recombination zone. The WOLED with bathocuproine (BCP) showed two separated emissions. The difference between two specimens was concluded by strong hole-blocking property of BCP. The introduction of BCP produced a recombination zone due to hole accumulation at the BCP interface.
