The relationship of solid-state plasticity to mechanochromic luminescence in difluoroboron avobenzone polymorphs
Date
2013
Authors
Krishna, Gamidi Rama
Mangalampalli, S.R.N. Kiran
Fraser, Cassandra L
Ramamurty, U
Reddy, C Malla
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John Wiley & Sons Ltd.
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.
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Keywords
Keywords: Avobenzone; Color changes; Crystal structure analysis; Design strategies; Energy defects; Mechanical action; Red-shifted emission; Slip plane; Colorimetry; Crystal engineering; Fluorophores; Mechanical properties; Nanoindentation; Polymorphism; Luminescen crystal engineering; mechanical properties; mechanochromic luminescence; nanoindentation; polymorphs
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Source
Advanced Functional Materials
Type
Journal article
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2037-12-31
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