Premium
Efficiency enhancement of InP‐based inverted QD‐LEDs by incorporation of a polyethylenimine modified Al:ZnO layer
Author(s) -
Kim Yohan,
Ippen Christian,
Fischer Bert,
Lange Alexander,
Wedel Armin
Publication year - 2015
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1002/jsid.322
Subject(s) - materials science , optoelectronics , light emitting diode , polyethylenimine , quantum dot , work function , layer (electronics) , diode , spin coating , nanotechnology , thin film , biology , genetics , cell culture , transfection
We report efficiency enhancement of indium phosphide (InP) quantum dot‐based light‐emitting diodes (QD‐LEDs) by using an polyethylenimine (PEI) surface modifier. By adapting a solution processed PEI layer on top of a aluminum doped zinc oxide (Al:ZnO) nanoparticle (NP) film, the leakage current of the inverted device was substantially suppressed. In addition, the electron injection into the conduction band edge (CBE) of InP/ZnSe/ZnS QDs was also facilitated by the low work function (WF) of the Al:ZnO film which was realized by the strong interfacial dipoles of the thin film of PEI. As a result, the charge balance in the inverted devices was controlled by the change of surface roughness, the WF and the thickness of neighboring layers via spin‐coating the PEI dissolved in alcohol mixture on the Al:ZnO layer such that the current efficiency was dramatically increased from 0.07 cd/A to 3.17 cd/A. The performance of our device is not comparable to Cd‐based devices; however, it shows the great potential for using an interfacial dipole layer to develop highly efficient InP‐based inverted QD‐LEDs.