Layered Dinitrostilbene-Based Molecular Solids with Tunable Micro/Nanostructures and the Reversible Fluorescent Response to Explosives

The ability to modulate and control the fluorescence properties of molecular solids at the micro/nanoscale is important to develop high-performance optoelectronic materials and sensors. Here we report the tunable one photon and two photon fluorescence as well as micro/nanostructures of dinitrostilbene-based (DNS) chromophore by the formation of layered multicomponent crystals with guanidinium cation (GD) through hydrogen bonding assembly. The as prepared GD(2)DNS bulk crystal shows a red shift emission as well as enhanced photoluminescence quantum yield and fluorescence lifetime compared with those of the Na2DNS sample, which is related to the structural transfer of DNS from staggered arrangement to parallel fashion within the crystal. Periodic density functional theoretical calculations further show that the introduction of different cationic units can modify the frontier orbital distribution and electronic structure of DNS anions within the multicomponent crystals. Moreover, one-dimensional GD(2)DNS nanobelts with well aligned orientation can be further obtained by a combined ultrasound and coprecipitation method. The GD(2)DNS nanobelts undergo a blue shift fluorescence compared with its bulk crystal, and exhibit alternated photoresponse (such as emission wavelength and intensity) upon interaction with different nitroaromatic explosives (trinitrotoluene, picric acid and m-dinitrobenzen). Therefore, this work gives a facile bottom up self assembly rout to prepare organic multicomponent materials with tunable fluorescence properties and micro/nanostructures, which can be potentially used as luminescence detector, for nitroaromatic explosives.