Vapochromism of hexaphenylsilole

The photoluminescence (PL) of the thin layer of hexaphenylsilole (HPS) on thin-layer chromatograph (TLC) or quartz plate is investigated. The PL of the HPS layer absorbed on the TLC plate can be turned "off'' and "on'' continuously and reversibly by solvent exposure and evaporation. On the other hand, the PL of the HPS film coated on the quartz plate becomes stronger with a blue-shift in its emission color after fumigation by solvent vapor. After solvent removal, the film does not return to its original blue-green emission. Analyses by SEM, TEM and XRD indicate that the transformation from amorphous to crystalline state is responsible for the vapor-induced stronger and bluer PL.