All-Inorganic Quantum-Dot Light-Emitting Diodes with Reduced Exciton Quenching by a MgO Decorated Inorganic Hole Transport Layer

Yibin Jiang; Le Jiang; Fion Sze Yan Yeung; Ping Xu; Shuming Chen; Hoi-Sing Kwok; Guijun Li

doi:10.1021/acsami.9b01742

All-Inorganic Quantum-Dot Light-Emitting Diodes with Reduced Exciton Quenching by a MgO Decorated Inorganic Hole Transport Layer

ACS Appl Mater Interfaces. 2019 Mar 27;11(12):11119-11124. doi: 10.1021/acsami.9b01742. Epub 2019 Mar 18.

Authors

Yibin Jiang¹, Le Jiang², Fion Sze Yan Yeung¹, Ping Xu², Shuming Chen³, Hoi-Sing Kwok¹, Guijun Li²

Affiliations

¹ State Key Lab on Advanced Displays and Optoelectronics , The Hong Kong University of Science & Technology , Clear Water Bay , Kowloon , Hong Kong.
² College of Electronic Science and Technology , Shenzhen University , Shenzhen , 518060 , P.R. China.
³ Department of Electrical and Electronic Engineering , Southern University of Science and Technology , Shenzhen , 518055 , P. R. China.

PMID: 30874422
DOI: 10.1021/acsami.9b01742

Abstract

Here, wide-bandgap magnesium oxide (MgO) is employed as a decorator for the nickel oxide (NiO _x) hole transport layer (HTL), by means of a bulk dopant as well as a surface modifier. QLEDs with Ni_0.88Mg_0.12O _x serving as the HTL achieve an ∼19.5% efficiency improvement compared to devices using pristine NiO _x. Further inserting an ultrathin MgO layer between the Ni_0.88Mg_0.12O _x and QDs to separate the accumulated charges from excitons goes on boosting the peak efficiency by another ∼35%. Finally, a maximum brightness over 40 000 cd/m² at 10 V is obtained, which is the highest among the reported values.

Keywords: all-inorganic quantum-dot light-emitting diodes; displays; electroluminescence quenching; inorganic hole transport layer; magnesium oxide.