Since receiving the Packard fellowship, I have been interested in the optical, electric and magnetic properties of colloidal nanoparticles. The current research is primarily in the infrared spectral range, where inorganic semiconductor quantum dots allow a wide spectral coverage by simply changing the size of the particles. My research group designs new colloidal quantum dots, explores the physical properties of the electronic transitions in intrinsic and doped quantum dots and studies the electronic coupling that can be achieved between particles. A potential practical outcome of our current research is to use nanoparticles films for making detectors of the thermal emission, at a fraction of the cost of existing technology. Our basic spectroscopy and electronic studies are in part motivated by the challenges of using such simple materials for a high-tech application.