Controlled Self-Assembly of Organic Microcrystals for Laser Applications

The small organic molecule <i>p</i>-distyrylbenzene (DSB) has been controllably prepared into one-dimensional microwires (1D-MWs) and 2D rhombic microdisks (2D-RMDs) by modulating the growth kinetics in the process of morphology growth. These as-prepared organic microcrystals, 1D-MWs and 2D-RMDs, exhibit a shape-dependent microcavity effect in that the single 1D-MW can act as a Fabry-Pérot (FP) mode lasing resonator while the individual 2D-RMD functions as the whispering-gallery-mode (WGM) microcavity. Moreover, as compared with the 1D FP resonators, there exists a higher quality factor (<i>Q</i>) in the WGM lasing resonator under the identical optical path length. Significantly, the lasing threshold, <i>E</i>_th = 1.02 μJ/cm², of 2D-RMDs is much lower than <i>E</i>_th = 2.57 μJ/cm² of 1D-MWs. Our demonstration can give the direction for the development of the organic solid-state microlasers