Linearly polarized emission from colloidal semiconductor quantum rods

Colloidal quantum rods of cadmium selenide (CdSe) exhibit linearly polarize d emission. Empirical pseudopotential calculations predict that slightly el ongated CdSe nanocrystals have polarized emission along the long axis, unli ke spherical dots, which emit plane-polarized light. Single-molecule lumine scence spectroscopy measurements on CdSe quantum rods with an aspect ratio between 1 and 30 confirm a sharp transition from nonpolarized to purely lin early polarized emission at an aspect ratio of 2. Linearly polarized lumine scent chromophores are highly desirable in a variety of applications.