We demonstrate efficient red phosphorescent organic light emitting diodes with a bipolar emission structure (D-EML) formed by two different layers doped with a red phosphorescent dye. Due to its self-balancing character, the recombination zone is shifted far from the emission/carrier-blocking-layer interfaces. This prevents the accumulation of carriers at the interfaces and reduces the triplet-triplet annihilation, resulting in an improved efficiency of the D-EML device compared with the standard single-EML architecture. However, a current efficiency of 8.4 cd A(-1) at 10 mA cm(-2) is achieved in the D-EML device compared with 3.7 cd A(-1) in the single-EML device.
Efficient red phosphorescent organic light emitting diodes with double emission layers
MAZZEO, MARCO;MARIANO, Fabrizio;MELCARNE, Angelo;CINGOLANI, Roberto;GIGLI, Giuseppe
2008-01-01
Abstract
We demonstrate efficient red phosphorescent organic light emitting diodes with a bipolar emission structure (D-EML) formed by two different layers doped with a red phosphorescent dye. Due to its self-balancing character, the recombination zone is shifted far from the emission/carrier-blocking-layer interfaces. This prevents the accumulation of carriers at the interfaces and reduces the triplet-triplet annihilation, resulting in an improved efficiency of the D-EML device compared with the standard single-EML architecture. However, a current efficiency of 8.4 cd A(-1) at 10 mA cm(-2) is achieved in the D-EML device compared with 3.7 cd A(-1) in the single-EML device.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
