High‐Quality White Organic Light‐Emitting Diodes Composed of Binary Emitters with Color Rendering Index Exceeding 80 by Utilizing Color Remedy Strategy

• Published in: Advanced functional materials Vol. 29; no. 11
• Main Authors: Tang, Xun, Liu, Xiang‐Yang, Jiang, Zuo‐Quan, Liao, Liang‐Sheng
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 14.03.2019
• Subjects: binary emitters; color remedy strategy; color rendering index; Color temperature; Diodes; Emitters; Energy dissipation; high efficiency; Materials science; Organic light emitting diodes; Power efficiency; Quantum efficiency; Rendering; Spectral emittance; white organic light‐emitting diodes
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201807541

Implementing rigorous standards for high‐quality white organic light‐emitting diodes (WOLEDs) demands further investigation. Herein, a novel and feasible color remedy strategy (CRS) is proposed in WOLEDs composed of binary‐emitters, to arouse the green‐emission, thereby complementing the spectral deficiency in white‐emission. Thus, the color rendering indexes (CRIs) of binary‐emissive WOLEDs can be boosted from 63 to 80 threshold, and the Commission International de I'Eclairage‐(x, y) coordinates are precisely located inside the American National Standard Institute quadrangles, which can rival the WOLEDs integrating ternary or more emitters. Moreover, it is more feasible for CRS‐based binary‐emissive system to tune white‐emission from cool white‐emission (correlated color temperature (CCT) ≈ 5000 K) to eye‐friendly warm white‐emission (CCT ≈ 2000 K). Meanwhile, benefiting from the reduced energy loss and low driving voltage of CRS zone, all of the CRS‐based WOLEDs with diverse CCTs can exceed 20% external quantum efficiency, and the highest approach 25%, as well as the highest power efficiency beyond 60 lm W−1, which is comparable with those reported employing light‐extracting techniques. In addition, it is evident that CRS‐based WOLEDs also exhibit outstanding color stability within the variation of luminance in several orders of magnitude (50–12 000 cd m−2). Thus, this novel CRS provides an innovative pathway to fabricate high‐quality WOLEDs composed of binary emitters. The color remedy strategy in binary‐emissive white organic light‐emitting diodes (WOLEDs) can effectively complement the green‐emission deficiency in a blue‐red binary‐emissive system by arousing the potential intensity of the shoulder peak in the blue emitter with lower exciton energy, thereby boosting the color rendering indexes of conventional binary‐emissive WOLEDs from 63 to in excess of 80 thresholds, as well as producing a high external quantum efficiency of 25%.