A detailed investigation of light-harvesting efficiency of blue color emitting divergent iridium dendrimers with peripheral phenylcarbazole units
- Authors
- Cho, Yang-Jin; Wee, Kyung-Ryang; Son, Ho-Jin; Cho, Dae Won; Kang, Sang Ook
- Issue Date
- 2014
- Publisher
- ROYAL SOC CHEMISTRY
- Citation
- PHYSICAL CHEMISTRY CHEMICAL PHYSICS, v.16, no.10, pp.4510 - 4521
- Indexed
- SCIE
SCOPUS
- Journal Title
- PHYSICAL CHEMISTRY CHEMICAL PHYSICS
- Volume
- 16
- Number
- 10
- Start Page
- 4510
- End Page
- 4521
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/101106
- DOI
- 10.1039/c3cp53797h
- ISSN
- 1463-9076
- Abstract
- The increase in phosphorescence efficiency was estimated by the energy transfer mechanism for divergent iridium dendrimers with peripheral phenylcarbazole units. A series of Ir-core/phenylcarbazole-end dendrons of the type, Ir(dfppy)(2)(pic-Cz(n)) (Gn, n = 0, 1, 2, and 3), was synthesized, where dfppy, pic, and Cz(n) (n = 2, 4, and 8) are 2-(4,6-difluorophenyl)pyridine, picolinate substituted with Cz(n) at the 3-position, and 4-(9-carbazolyl)phenyldendrons connected with 3,5-di(methyleneoxy)benzyloxy branches, respectively. Selective excitation of the Cz(n) units of G1-G3 resulted in >90% quenching of the Cz fluorescence accompanied by the growth of phosphorescence from the Ir(dfppy) 2(pic) core as a consequence of energy transfer from the excited-singlet Cz(n) chromophore to the core. The rate constants of energy transfer were determined by steady-state and transient spectroscopic measurements to be 4.32 x 10(9) s(-1) (G1), 2.37 x 10(9) s(-1) (G2), and 1.46 x 10(9) s(-1) (G3), which were in good agreement with those calculated using the Forster model. The phosphorescence enhancements were 157 (G1), 213 (G2), and 264% (G3) when compared to the phosphorescence of the core Ir(dfppy)(2)(pic-Ph-2) (G0), in which pic-Ph-2 is 3-(3,5-dibenzyloxybenzyl) picolinate.
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Collections - Graduate School > Department of Advanced Materials Chemistry > 1. Journal Articles
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