Laboratory of Nano-Bioengineering improves characteristics of quantum dot based light-emitting diodes: Paper in the top-rated Scientific Reports


Pavel Samokhvalov and Maria Zvaigzne, researchers of the Laboratory of Nano-Bioengineering (LNBE) of NRNU MEPhI, and Prof. Igor Nabiev, leading scientist of LNBE, in collaboration with A.E. Alexandrov and D.A. Lypenko, of the Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences, have published a study on Al-, Ga-, Mg-, or Li-doped zinc oxide nanoparticles as electron transport layers for quantum dot light-emitting diodes. The study appeared in the Scientific Reports, a top-rated journal published by the Nature Publishing Group.

The authors have analyzed how the doping of ZnO nanoparticles constituting the electron-transport layer (ETL) with Al, Ga, Mg, and Li affects the characteristics of quantum dot–based light-emitting diodes (QLEDs), next-generation light-emitting devices.

Colloidal quantum dots are promising materials for optoelectronic devices. The controllable spectral position of the peak and high quantum yield of the quantum dot luminescence make it possible to engineer highly efficient light-emitting diodes and displays with a large color range. The use zinc oxide nanoparticles as the material for ETL allowed the characteristics of QLEDs to be dramatically improved. A high electron mobility in the ZnO layer and the possibility of fine tuning of the energy bands by doping the nanoparticles has resulted in considerably increased brightness and current efficiency of the devices.

Since the first use of ZnO nanoparticles as the material for ETL, various doping strategies have been proposed that allowed the enhancement of QLED characteristics by optimizing the energy diagram of the device, modulating the electron transport, and decreasing unwanted migration of charge carriers between the active layer of quantum dots and the ETL. However, there is no clear choice of the ZnO-based ETL material, because doping with different elements yields devices with similar characteristics. The authors of the published study estimated the effects of different dopants on the QLED characteristics and performed comparative analysis.

It has been found that doping of the ETL material with aluminum ensures the best characteristics of the device in terms of brightness, current efficiency, and turn-on voltage due to the high electrical conductivity of aluminum and low roughness of its surface. The results of the study will be useful for the selection of the optimal ETL materials in future QLED developments.

Scientific Reports is a top-rated international journal of the Nature group publishing only original studies and developments. The journal has permanently been in the first quartile of interdisciplinary journals in SCImago's Scientific Journal Ranking (SJR) almost since its foundation.


Pavel S. Samokhvalov, Ph.D., senior researcher, head of the Nanochemistry Group of LNBE (

Maria A. Zvaigzne, postgraduate student, research engineer (

Maria G. Korenkova, director of public relations (

Laboratory of Nano-Bioengineering (LNBE),
National Research Nuclear University MEPhI,
31 Kashirskoe shosse, 115409 Moscow, Russian Federation

© 2012 Laboratory of Nano-BioEngineering