BROWSE

Related Scientist

Choi, Jung Kweon's photo.

Choi, Jung Kweon
나노물질 및 화학반응 연구단
more info

ITEM VIEW & DOWNLOAD

Inter-Ligand Energy Transfer Process in an Ir-Complex with Expanding π-Conjugated Ligand

Cited 0 time in webofscience Cited 0 time in scopus
13 Viewed 0 Downloaded
Title
Inter-Ligand Energy Transfer Process in an Ir-Complex with Expanding π-Conjugated Ligand
Author(s)
Jeongwook Hwang; Mina Ahn; Jungkweon Choi; Kyung-Ryang Wee
Subject
inter-ligand energy transfer, ; iridium complex, ; phosphorescence, ; species-associated spectra, ; π-expanding effect
Publication Date
2020-10
Journal
CHEMPHYSCHEM, v.21, no.20, pp.2320 - 2326
Publisher
WILEY-V C H VERLAG GMBH
Abstract
© 2020 Wiley-VCH GmbH. The inter-ligand energy transfer (ILET) process in heteroleptic iridium complex, [Ir(dfppy)2(bpy-Im2)]+, where dfppy=2-(2,4-difluorophenyl)pyridine and bpy-Im2=4,4’-bis(1,2-diphenyl-1H-benzo[d]imidazole)-2,2’,-bipyridine, was investigated using a femtosecond transient absorption (fs-TA) spectroscopic technique. The photophysical properties of [Ir(dfppy)2(bpy-Im2)]+ with significantly expanding π-conjugated ligand are compared to those of [Ir(dfppy)2(bpy)]+ (bpy=2,2’-bipyridine) and a free bpy-Im2 ligand. The emission spectrum of [Ir(dfppy)2(bpy-Im2)]+ shows no shift upon changing the solvent polarity, whereas the free ligand bpy-Im2 showed bathochromic fluorescence shifts with increasing solvent polarity, which is attributed to intramolecular charge transfer (ICT). The unique photophysical properties of [Ir(dfppy)2(bpy-Im2)]+ are due to the fast ILET process from 3MLCTdfppy to 3MLCT/3LCbpy-Im2, resulting in the phosphorescence emission originating from 3MLCT/3LCbpy-Im2. On the other hand, the TA bands of bpy-Im2 are observed at 540 and 480 nm, corresponding to the singlet and triplet manifolds, respectively. In contrast, the TA spectrum of [Ir(dfppy)2(bpy-Im2)]+ showes broad bands centered at 420 and 600 nm, attributed to the transitions from 3MLCTdfppy and 3MLCT/3LCbpy-Im2, respectively. Time-resolved spectroscopic results confirm the efficient ILET dynamics from 3MLCTdfppy to 3MLCT/3LCbpy-Im2 in [Ir(dfppy)2(bpy-Im2)]+. From the relaxation times determined by singular value decomposition analysis and simple sequential kinetic model, we infer that the ILET process from 3MLCTdfppy to 3MLCT/3LCbpy-Im2 occurs with a time constant of ca. 4 ps. The presented results in this study show that the introduction of an expanding π-conjugated ligand can lead to the efficient ILET dynamics for improving the OLED performance
URI
https://pr.ibs.re.kr/handle/8788114/7598
DOI
10.1002/cphc.202000565
ISSN
1439-4235
Appears in Collections:
Center for Nanomaterials and Chemical Reactions(나노물질 및 화학반응 연구단) > 1. Journal Papers (저널논문)
Files in This Item:
There are no files associated with this item.

qrcode

  • facebook

    twitter

  • Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.
해당 아이템을 이메일로 공유하기 원하시면 인증을 거치시기 바랍니다.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse