Blinking Semiconducting Nanorods

Several clusters of semiconducting nanorods are being illuminated by blue light. The nanorods absorb blue light, become excited and emit red light. The emission of light by individual nanorods occurs in a random fashion with the nanorod turning "on" and "off" for variable lengths of time.


Antibody Functionalized Sensor

Schematic of an antibody-functionalized graphene FET sensor.  Prof. Charlie Johnson functionalizes a graphene strip with an antibody to a Lyme disease biomarker protein.  The insulating substrate is shown in pink.  When antigen molecules bind to the antibody, the electrical characteristics of the FET are altered.

Topological Insulators

Recent physics research shows how spin-orbit coupling can rearrange electronic bands in a solid to make a "topological insulator" - a new quantum phase of matter with conductive surfaces even though its bulk is insulating.  Penn physicists Professor Charlie Kane and Professor Gene Mele pioneered the theoretical discovery of such materials in 2005.


Functional Imaging in the Brain

A representation of blood flow changes in a rat brain during cortical spreading depression. In the experiment, a large local concentration of KCl initiates a 'wave' of neuronal depolarization that propagates outward from a central point and then repeats itself.  The figure shows images of blood flow in four parallel planes located within 3 millimeters of the skull.


Extrasolar Planet Searches

Prof. Cullen Blake studies stars of late-M and L spectral types, collectively known as Ultracool Dwarfs, searching for Earth-size planets which transit the star. Telluric lines are used as a wavelength reference for radial velocity measurements at deep red and near infrared wavelengths.