Growth of organic nonlinear nanowires through a one-drop self-assembly method

Abstract

In our previous study, we demonstrated that a surface supported rapid evaporation crystallization (SSREC) method can be utilized to effectively prepare single nanometer nanocrystals (NCs) of 4-N, N-dimethylamino-4’-N’-methylstilbazolium tosylate (DAST), a bench mark of organic nonlinear optical (NLO) crystal. In this study, first, we extend the SSREC method to DAST single crystal nanowires (NWs) preparation by using a polymer-type surfactant. With one-drop of DAST-methanol solution, millimeter-scale the DAST NWs can be attained within one minute. We presume that this highly efficient driving forces of the fast self-assembling process originate from Coulombic interactions of the DAST nanocrystals. In order to further increase the crystal quality of the NWs, we propose a one-drop self-assembly process which separates the SSREC self-assembling process into two steps: SSREC process for NCs preparation and static cultivation process for NWs self-assembly. By this method, we successfully attain 4-N, N-dimethylamino-4'-N'-methylstilbazolium 2-naphthalenesulfonate (DSNS-2) NWs. The obtained DSNS-2 NWs have very high surface quality with surface roughness <150 pm, which is highly beneficial for fabricating integrated optical devices. Furthermore, the onedrop self-assembly method only requires reagents in microgram quantities, and thus this method is extremely environment-friendly.