Use of Hybrid PEDOT:PSS/Metal Sulfide Quantum Dots for a Hole Injection Layer in Highly Efficient Green Phosphorescent Organic Light-Emitting Diodes.

Kuangyu Ding,Bin Wei,Wenqing Zhu,Jun Li,Lu Huang,Chen Yi,Ruilin Chen

doi:10.3389/fchem.2021.657557

Abstract

In this study, we have synthesized the molybdenum sulfide quantum dots (MoS2 QDs) and zinc sulfide quantum dots (ZnS QDs) and demonstrated a highly efficient green phosphorescent organic light-emitting diode (OLED) with hybrid poly (3,4-ethylenedioxythiophene)/poly (styrenesulfonate) (PEDOT:PSS)/QDs hole injection layer (HIL). The electroluminescent properties of PEDOT:PSS and hybrid HIL based devices were explored. An optimized OLED based on the PEDOT:PSS/MoS2 QDs HIL exhibited maximum current efficiency (CE) of 72.7 cd A−1, which shows a 28.2% enhancement as compared to counterpart with single PEDOT:PSS HIL. The higher device performance of OLED with hybrid HIL can be attributed to the enhanced hole injection capacity and balanced charge carrier transportation in the OLED devices. The above analysis illustrates an alternative way to fabricate the high efficiency OLEDs with sulfide quantum dots as a HIL.

Highlights

New-generation organic light-emitting diodes (OLEDs) have attracted huge research interests due to their unique properties such as high color purity, light weight and flexibility (Liao et al, 2004; Wen et al, 2005; Wang et al, 2018; Wang et al, 2020)
The small contact angles reveal that the hybrid PEDOT:PSS/quantum dots (QDs) hole injection layer (HIL) has strong hydrophilic and spread-ability, resulting in a better interface and adhesion between anode and hole transporting layer (Phatak et al, 2012; Tsai et al, 2020)
Within the green emission spectral range, the glass substrate with hybrid PEDOT:PSS/zinc sulfide quantum dots (ZnS QDs) and PEDOT:PSS/ MoS2 QDs film with the concentration of 10% yielded a higher transmittance of 93% at 525 nm which is beneficial for enhancing the light extraction in OLED devices with normal configuration (Yang et al, 2014; Chiu and Chuang, 2015)

Summary

Introduction

New-generation organic light-emitting diodes (OLEDs) have attracted huge research interests due to their unique properties such as high color purity, light weight and flexibility (Liao et al, 2004; Wen et al, 2005; Wang et al, 2018; Wang et al, 2020). The water contact angles of neat PEDOT:PSS and hybrid PEDOT:PSS/QDs with the concentration of 10% (v/v) on the glass substrate were measured to identify the hydrophilic and spread-ability of the resulting HILs, which could affect the filmforming property of hole transporting layer (HTL) (Yu et al, 2014; Singh et al, 2014; Huang et al, 2009; Cho et al, 2014).

Results

Conclusion