Structural optimizing carrier recombination for efficient blue phosphorescence organic light-emitting diode with ambipolar host
Journal
IEEE Journal on Selected Topics in Quantum Electronics
Journal Volume
22
Journal Issue
1
Pages
7274662
Date Issued
2016
Author(s)
Abstract
A high-efficiency blue phosphorescence organic lightemitting diode (OLED) with a new ambipolar organic compound, 9-(2-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl)-9H-carba zole (CbzTAZ) as the host, structurally engineered the emitting layer (EML) and electron-transporting layer (ETL) to achieve the great carrier balance in the EML. The chemical structure of CbzTAZ contains an electron-transporting 1,2,4-triazole segment and a hole-transporting carbazole ring. By scanning the composite ratio between the CbzTAZ host and the blue emitter iridium(III)bis[4,6(di-fluorophenyl)-pyridinato-N,C2']picolinate to be an efficient EML, and then by fine-tuning the layer thicknesses of the ETL and EML, a highly efficient blue PhOLED was obtained because of the improved electron-hole balance and broad recombination zone coverage in the EML. The blue PhOLED exhibited a maximum current efficiency (ηC) of 48 cd/A, a power efficiency (ηP ) of 42.2 lm/W, and an external quantum efficiency (ηEQ E) of 22.9%. In addition, the device demonstrated a satisfactory efficiency rolloff (ηC of 41.1 cd/A, ηP of 18.1 lm/W, and ηEQE of 19.8%) at a high brightness value of 1000 cd/m 2 .
SDGs
Type
journal article