The Relationship of Solid-State Plasticity to Mechanochromic Luminescence in Difluoroboron Avobenzone Polymorphs

Krishna, Gamidi Rama and Kiran, Mangalampalli SRN and Fraser, Cassandra L and Ramamurty, Upadrasta and Reddy, Chilla Malla (2013) The Relationship of Solid-State Plasticity to Mechanochromic Luminescence in Difluoroboron Avobenzone Polymorphs. In: ADVANCED FUNCTIONAL MATERIALS, 23 (11). pp. 1422-1430.

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Abstract

In solid-state mechanochromic luminescence (ML) materials, it remains a challenge to establish the origin of fluorescence color changes upon mechanical action and to determine why only some fluorophores exhibit ML behavior. The study of mechanical properties by nanoindentation, followed by ML experiments on green- and cyan-emitting polymorphs of difluoroboron avobenzone reveals that upon smearing, the plastically deformable cyan form shows a prominent color change to yellow, while in the harder green form the redshifted emission is barely detectable. Crystal structure analysis reveals the presence of slip planes in the softer cyan form that can facilitate the formation of recoverable and low energy defects in the structure. Hence, the cyan form exhibits prominent and reversible ML behavior. This suggests a potential design strategy for efficient ML materials.

Item Type:	Journal Article
Publication:	ADVANCED FUNCTIONAL MATERIALS
Publisher:	WILEY-V C H VERLAG GMBH
Additional Information:	Copyright for this article belongs to the WILEY-V C H VERLAG GMBH, GERMANY.
Keywords:	crystal engineering; mechanochromic luminescence; mechanical properties; nanoindentation; polymorphs
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	17 Apr 2013 11:49
Last Modified:	18 Apr 2013 05:26
URI:	http://eprints.iisc.ac.in/id/eprint/46385

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