High-Performance Red Phosphorescent Organic Light-Emitting Diodes Based on a Gradient-Doped Emitting Layer

Abstract:

Recently the phosphorescent organic light-emitting diodes (PhOLEDs) have attracted tremendous attention owing to their extremely high performance. However, PhOLEDs always suffer from the annihilation and quenching of excitons due to higher guest doping concentration. In this work, to obtain a high efficiency red PhOLED, a gradient-doped emitting layer (EML) was employed in the device to improve the device efficiency and suppress the annihilation of excitons. A significant enhancement in terms of current efficiency (CE) and power efficiency (PE) of PhOLEDs with optimized gradient-doped EML was realized with the maximum CE of 13.84 cd A^-1 and PE of 18.11 lm W⁻¹, which are 33.9% and 60.7% higher than that of the control device, respectively. The enhanced performance of the PhOLEDs is attributed to the lower guest doping concentration in gradient-doped EML and balanced hole/electron recombination, leading to the reduced triplet-triplet annihilation and triplet-polaron quenching. The simple strategy opens a new avenue for fabricating high-performance PhOLEDs.

• Periodical: Materials Science Forum (Volume 976)
• Pages: 110-115
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.976.110
• Online since: January 2020
• Authors: Fei Yang Liu, Bin Wei, Guo Chen*
• Keywords: Gradient-Doped Emitting Layer, High-Performance, Phosphorescent Organic Light-Emitting Diodes

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