20November2017

Nano-Micro Letters

Regulating Charge and Exciton Distribution in High-Performance Hybrid White Organic Light-Emitting Diodes with n-Type Interlayer Switch

Dongxiang Luo1, Yanfeng Yang1, Ye Xiao1, Yu Zhao1, Yibin Yang1, Baiquan Liu2,3,*

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Nano-Micro Lett. (2017) 9: 37

First Online: 26 January 2017 (Article)

DOI:10.1007/s40820-017-0138-4

*Corresponding author. E-mail: bqliu@ntu.edu.sg

 

Abstract

 


Fig. 1 Top: Schematic layer structure of the WOLED. Bottom: Chemical structure of emitters.

The interlayer (IL) plays a vital role in hybrid white organic light-emitting diodes (WOLEDs); however, only a negligible amount of attention has been given to n-type ILs. Herein, the n-type IL, for the first time, has been demonstrated to achieve a high efficiency, high color rendering index (CRI), and low voltage trade-off. The device exhibits a maximum total efficiency of 41.5 lm W–1, the highest among hybrid WOLEDs with n-type ILs. In addition, high CRIs (80–88) at practical luminances (≥ 1000 cd m–2) have been obtained, satisfying the demand for indoor lighting. Remarkably, a CRI of 88 is the highest among hybrid WOLEDs. Moreover, the device exhibits low voltages, with a turn-on voltage of only 2.5 V (> 1 cd m–2), which is the lowest among hybrid WOLEDs. The intrinsic working mechanism of the device has also been explored; in particular, the role of n-type ILs in regulating the distribution of charges and excitons has been unveiled. The findings demonstrate that the introduction of n-type ILs is effective in developing high-performance hybrid WOLEDs.


 

Keywords

White light; Hybrid; Interlayer; Color rendering index; Organic light-emitting diodes

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