Monday, November 5, 2018 - 16:00
Event Speaker: 
Matthew Graham
Local Contact: 
Matthew Graham

How can we best harvest photoexcited electrons in emerging nanomaterials to enable higher solar efficiencies and faster optoelectronics? The Micro-Femto Energetics Lab develops novel spectroscopy and transport methods that resolve photoexcited electron dynamics with both micron (~10-6 m) spatial resolution and femtosecond (10-15 s) time-resolution.  By creating theses ultrafast movies at single crystal grain level, we can resolve the journey of photocurrent generation; from light absorption to electron extraction.  Specifically, we develop ‘on-chip’ microscopy movies that use femtosecond-photocurrent and transient absorption responses from individual crystal grains of bilayer 2D materials.  By twisting the layer stacking orientation and applying E-field, we show how long-range interlayer electronic coupling of both graphene and other 2D semiconducting materials fundamentally alter the material photophysics.    This new approach further enables us to selectively image the rate-limiting electron-hole dissociation bottleneck processes which intrinsically control new material’s potential for next-generation solar and optoelectronic applications. We will further have the audience interact with these novel optoelectronic principles using a hands-on 'labs-to-lecture' discovery approach. 

Refreshments will be offered half an hour before the colloquium in Weniger 379