The vision of IRG-4 is to explore nanoparticle-based materials that are non-toxic, environmentally benign, abundant, stable and economically manufacturable, and to understand their fundamental optoelectronic properties for luminescent and photovoltaic (solar-to-electric energy conversion) applications. The IRG focuses on semiconductor nanoparticles including group IV materials (Si and Ge) and several metal-oxides, whose constituent elements are among the most abundant in the earth's crust and non-toxic. Materials that are assembled from such semiconductor nanoparticles have great potential for applications in photovoltaics, thermoelectrics, solid-state lighting, and electroluminescent displays. Compared to bulk materials or thin films, the utilization of nanoparticles in these areas has several advantages: (i) the properties of the particles may be tailored by controlling their size, (ii) new physical phenomena, not present in the bulk or thin film, may be exploited, (iii) nanoparticles may be deposited at low cost from the gas or liquid phase through established coating and printing techniques (e.g. ink jet-printing), and (iv) nanoparticle-assembly approaches confer many new degrees of freedom in device design. The IRG-4 research team is vertically integrated and includes expertise from the synthesis of nanoparticles, to their photo-physical and structural characterization, to their evaluation in actual devices.

IRG 4 research areas
Synthesis, functionalization and doping of nanocrystals
Interfacial charge carrier transport
Nanoparticle integration into luminescent and photovoltaic devices

The principal investigators and their primary areas of expertise are:

Eray Aydil - Materials synthesis, surface chemical characterization
Stephen Campbell - Electronic properties and characterization
Alexander Efros (NRL)- Theory of photophysics and electronic transport
Uwe Kortshagen, program leader - Nanoparticle synthesis, electronic materials
Andre Mkhoyan - Analytical Microscopy and Spectroscopy
David Norris - Photo-physical properties of nanoparticles
R. Lee Penn - Structural characterization by electron microscopy