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| Type |
Poster Presentation |
| Area |
물리화학 |
| Room No. |
포스터발표장 |
| Time |
4월 20일 (목요일) 11:00~12:30 |
| Code |
PHYS.P-49 |
| Subject |
Investigating emitter orientation in host-guest films with angle-dependent photoluminescence (PL) measurement |
| Authors |
이준호, 이치호, 박성남*
고려대학교 화학과, Korea
|
| Abstract |
Small molecule organic light-emitting diodes (SM-OLEDs) have been developed as a distinctive device. So far, a low outcoupling efficiency has still been a challenge to enhance the external quantum efficiency (EQE), even though the intrinsic quantum efficiency reaches almost 100%. One of the suggestion to increase the outcoupling efficiency in amorphous SM-OLEDs is implementing horizontally oriented emitters inside host molecules. In the case of a host-guest system which has been commonly used in thermally activated delayed fluorescence (TADF) OLEDs, and phosphorescence OLEDs (Ph-OLEDs), angle-dependent PL measurements have been used to determine the molecular orientation. Moreover, two anisotropic refractive indices which are obtained by variable angle spectroscopic ellipsometry (VASE) measurements are required for a determination of emitter orientation as fitting parameters. In this work, instead of using uniaxial refractive indices determined from the VASE, we propose an alternative method using an effective refractive index to fit angle-dependent PL data. Employing this method, we have verified that the molecular orientation of dopants is not dependent on the film thickness and the high aspect ratio of dopant molecules is a major factor to give the horizontal orientation of dopants. Overall, our present method is shown to be reliable and thus it is utterly promising to examine the molecular orientation of emitters in various host-guest systems. |
| E-mail |
pplkjh2@naver.com |
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119th General Meeting of the KCS