Fluorescence dynamics of biphenyl-ester moieties of two- or three-dimensional phases of a thermotropic liquid crystal were explored. In the 2D crystalline-to-3D cubic phase transition, a broad excitation band centered at 280 nm and a 10 nm fluorescence redshift were observed. A drastic change in the fluorescence time-decay constant from ∼90 to ∼130 ps was seen. These changes resulted from cooperative contribution of intermolecular configurational change from biphenyl-biphenyl to biphenyl-ester and polarity alterations surrounding the charge transfer emissive chromophores. The material exhibited higher charge transfer emissions in the cubic and columnar 3D phases than in the 2D crystalline phase. Crown
Bibliographical noteFunding Information:
We thank Dr. M. Lee for providing the high quality rod-coil molecule used in this study. Research at GIST was funded by the APRI Research Program of GIST, from the Basic Science Research Program . Financial support was provided through the National Research Foundation funded by the Korean Government (Ministry of Education, Science and Technology , No. 2011-0006563 ), and through the EI Project ARQ20114000114 (401-112-014) funded by the Korea Ministry of Environment . Research at Yonsei was funded by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare and Family Affairs (Grant No. A121133 ).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry