Open AccessImportance of Purcell factor for optimizing structure of organic light-emitting diodes
Author(s) -
Hyunsu Cho,
Jaiho Chung,
Jinouk Song,
Jae-Ho Lee,
Hyunkoo Lee,
Jonghee Lee,
Jaehyun Moon,
Seunghyup Yoo,
Nam Sung Cho
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.011057
Subject(s) - oled , electroluminescence , diode , optoelectronics , quantum efficiency , spontaneous emission , materials science , optics , light emitting diode , purcell effect , dipole , physics , nanotechnology , laser , layer (electronics) , quantum mechanics
The ratio of spontaneous emission inside a diode structure to that in free space is called the Purcell factor (F(λ)). The structure of organic light-emitting diodes (OLEDs) has a significant influence on the spontaneous emission rate of dipole emitters. Therefore, to describe the optical properties of OLEDs, it is essential to incorporate F(λ) in the description. However, many optical studies on OLEDs continue to be conducted without considering F(λ) for simplicity's sake. Hence, in this study, using carefully designed bottom- and top-emitting OLEDs, we show that the external quantum efficiency obtained without considering F(λ) can be over- or under-estimated, and in some cases, the margin of error may be significant. We also reveal that the subtle distribution of the electroluminescence spectrum can be explained properly only by including F(λ). Both these results stipulate the importance of including F(λ) to maintain a quantitative agreement between theoretical and experimental data. Hence, the inclusion of F(λ) is important for designing OLEDs with enhanced efficiency or desired spectral characteristics.