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

Journal Title

Journal ISSN

Volume Title

Publisher

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.

Description

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

Citation

Source

Advanced Functional Materials

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

Restricted until

2037-12-31