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Fast Photoluminescence Switching in the Nematic Phase of Calamitic–Discotic Composites
Author(s) -
Madhuri P. Lakshmi,
Rao D. S. Shankar,
Yelamaggad Channabasaveshwar V.,
Achalkumar Ammathnadu S.,
Prasad S. Krishna
Publication year - 2015
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201500126
Subject(s) - liquid crystal , materials science , photoluminescence , dopant , phase (matter) , diffraction , optoelectronics , optics , anisotropy , fluorescence , doping , chemical physics , organic chemistry , physics , chemistry
A photoluminescent (PL) system comprising a host calamitic–nematic and discotic fluorescent dopant is presented which can be switched at fast rates between two anisotropic values of photoluminescence using a two‐frequency addressing scheme. The employed unprecedented protocol, exhibiting the desirable higher contrast, switches two orders of magnitude faster than the standard mode of addressing. The methodology employed can be generalized and thus caters to a variety of fluorophores to cover the required PL wavelength. On the basis of X‐ray diffraction results it is demonstrated that as the discotic content is increased, the extent and nature of the short‐range order in the nematic phase changes, from that of a standard nematic to that of the locally columnar type. Imposing geometrical restrictions on this active system through a network of hydrogen‐bonded nanoparticles yields higher emission in both the field‐on and field‐off situations, although with a reduced anisotropy.