Improved efficiency in fluorescent blue organic light emitting diode with a carrier confining structure

A blue organic light emitting device (OLED) with improved efficiency and good color purity is reported. The highest occupied molecular orbital (HOMO) level of the hole transport layer (HTL) and that of the emissive layer (EML) differs by 0.3 eV. This energy level mismatch confines the carriers at th...

Full description

Saved in:

Bibliographic Details
Published in:	Organic electronics Vol. 10; no. 7; pp. 1201 - 1208
Main Authors:	Samal, Girija S., Narayanan Unni, K.N., Bharat, Saswat, Gupta, Shubham, Deepak
Format:	Journal Article
Language:	English
Published:	Amsterdam Elsevier B.V 01-11-2009 Elsevier
Subjects:	Applied sciences Blue fluorescence Carrier confinement Electronics Exact sciences and technology Optoelectronic devices Organic light emitting diode Organic semiconductor Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices Carrier confinement 78.20Jq 78.60Fi 78.66Qn Blue fluorescence Organic semiconductor Organic light emitting diode 72.80Le Performance evaluation Molecular orbital Hole transport layer Blocking layer Multiple layer Charge transport Mismatching Light emitting device Organic light emitting diodes Optoelectronic device Organic semiconductors Chromaticity Blue light Simulator Gain Organic electronics
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	A blue organic light emitting device (OLED) with improved efficiency and good color purity is reported. The highest occupied molecular orbital (HOMO) level of the hole transport layer (HTL) and that of the emissive layer (EML) differs by 0.3 eV. This energy level mismatch confines the carriers at the HTL/EML interface. Conventional devices have only one HTL/EML interface, with a current efficiency of 2.9 cd/A. Without adding a separate hole blocking layer, incorporating multi-layers of the same HTL and EML increases this efficiency to 5.8 cd/A, with only a small increase in operating voltage yielding increased power efficiency also. But, there are an optimum number of layers, beyond which efficiency loss results. Also, including the multilayer structure simultaneously improves the blue color co-ordinates. To gain insight into the role of multilayer structures in modifying charge transport and recombination zone a simulator was developed. The simulated results could qualitatively explain the experimental observations.
ISSN:	1566-1199 1878-5530
DOI:	10.1016/j.orgel.2009.06.009