Self-assembled CdSe/CdS nanorod micro-lasers fabricated from solution by capillary jet deposition

Here we show an innovative, simple and reliable method to fabricate micro-lasers by self-assembly of rod-shaped nanocrystals. We use dot/rod core/shell CdSe/CdS nanorods to form optical micro-resonators by exploiting their self-organization into well-defined coffee stain rings. The fabrication process merely consists of capillary jet deposition of a nanorod solution onto a glass substrate, and is scalable, economic, and highly reproducible. Upon optical pumping of the micro-resonators we obtain laser emission in the red or in the blue-green spectral region, demonstrating lasing both from core and shell transitions, with low pumping thresholds. Modeling by full-wave numerical simulations according to generalized (i. e. scattering) formulation of laser theory demonstrates lasing from complex modes of the self-assembled cavity.