High-performance green phosphorescent top-emitting organic light-emitting diodes based on FDTD optical simulation

• FDTD method is applied in TOLEDs for optical optimization, demonstrating good agreement with experimental data.
• A mixed host with bipolar transport property is employed to avoid charge accumulation and broaden the recombination zone.
• A current efficiency of 127.0 cd/A at 1000 cd/m2 is obtained, and maintains to 116.3 cd/A at 10,000 cd/m2.
• The resulting TOLED exhibits a highly saturated color, as well as hardly detectable color shift with viewing angles.

We have successfully applied finite-difference time-domain (FDTD) method in top-emitting organic light-emitting diodes (TOLEDs) for structure optimization, demonstrating good agreement with experimental data. A mixed host with both hole transport and electron transport materials is employed for the green phosphorescent emitter to avoid charge accumulation and broaden the recombination zone. The resulting TOLEDs exhibit ultra-high efficiencies, low current efficiency roll-off, and a highly saturated color, as well as hardly detectable spectrum shift with viewing angles. In particular, a current efficiency of 127.0 cd/A at a luminance of 1000 cd/m2 is obtained, and maintains to 116.3 cd/A at 10,000 cd/m2.

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