Suppression of the Efficiency Roll-Off Characteristics in Solution-Processed Lanthanide-based Organic Light-Emitting Diodes
Loading...
Authors
Shahalizad Namin, Afshin
Date
Type
thesis
Language
eng
Keyword
Organic Light-Emitting Diodes , Lanthanide Complex , Efficiency Roll-Off , Near Infrared Electroluminescence
Alternative Title
Abstract
Organic light-emitting diodes (OLEDs) have gained a tremendous amount of interest, due to their applications in display and solid-state lighting technologies. This interest mainly arises from the easy and inexpensive manufacturing processes for the fabrication of lightweight, transparent, flexible, and large-area devices. While OLEDs have now reached the stage of commercialization, there are still some serious issues associated with exciton-exciton and exciton-polaron annihilation mechanisms, which reduce their efficiency particularly under the high current densities required to achieve a high level of brightness. This phenomenon is known as efficiency roll-off. On the other hand, since most luminescent organic semiconductors are in principle four-level lasing systems, color-tunable and easy-to-manufacture optically pumped organic solid-sate lasers (OSLs) have attracted a lot of attention, due to their applications in biological sensing, spectroscopy, and data communication. However, highly demanded portable electrically driven continuous-wave (CW) OSLs (organic diode lasers) have not been realized to date. This is mainly because of the above-mentioned efficiency roll-off issue under the high current densities required to achieve lasing threshold in OLEDs.
Visible-emitting trivalent lanthanide ions (Ln3+) are promising emitters for OLED applications. They are also known for their excellent lasing properties, owing to their long excited-state lifetimes, favoring population inversion in optically pumped plastic lasers and amplifiers. Furthermore, near infrared (NIR)-emitting trivalent lanthanide ions are important emitters in telecommunication applications in the 900-1600 nm spectral range. Despite the fact that lanthanide-based emitters have been studied in the NIR-emitting OLEDs, their efficiency is still much lower than in their visible-emitting counterparts. Moreover, like other types of OLED, lanthanide-based devices suffer from the aforementioned efficiency roll-off mechanisms. In the present thesis, we show enhanced efficiency from solution-processed NIR-emitting lanthanide-based OLEDs. We also demonstrate unprecedented low efficiency roll-off characteristics in both visible and NIR-emitting lanthanide-based devices.
Description
Citation
Publisher
License
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.