Alkyl chain length effects on solid-state difluoroboron beta-diketonate mechanochromic luminescence

作者：Nguyen Nguyen D; Zhang Guoqing; Lu Jiwei; Sherman Arianna E; Fraser Cassandra L^*

来源：Journal of Materials Chemistry, 2011, 21(23): 8409-8415.

DOI：10.1039/c1jm00067e

Solid-state difluoroboron beta-diketonate dyes display reversible mechanochromic luminescence (ML). To test the effects of alkyl chain length on solid state photoluminescence and ML, a series of dyes, BF(2)dbmOR, with dibenzoylmethane (dbm) ligands and alkoxyl substituents (-OR) were prepared, where R C(n)H(2n+1) and n = 1, 2, 3, 5, 6, 12, 14, 16, 18. Emission properties were investigated in solution and in the solid state. Fluorescence spectra and lifetimes were nearly identical for dyes in CH(2)Cl(2) solution; whereas, in the solid state, as powders, thin films or spin cast films, emission maxima, and lifetimes were different among the samples. Solid-state ML emission spectra were monitored at room temperature as a function of time for smeared powders on quartz surfaces. The recovery time generally increased with alkyl chain length, ranging from minutes (n = 3) to days (n = 18). Longer chain analogues (n = 6, 12, 14, 16, 18) did not fully return to the original annealed emissive state even after months on quartz, though the dynamics are substrate dependent. Solid-state dyes were also investigated by XRD and DSC (powders), and by AFM (spin cast films).

• 出版日期2011