Braun Group People
Kevin Arpin
Graduate Student in Materials Science and Engineering
B.S. in Biomedical Engineering at University of Connecticut (2008)
Thermal Photovoltaics
The conversion of thermal radiation to electricity via a thermal photovoltaic (TPV) cell has the potential of achieving extremely high efficiencies using single junction solar cells. These cells function by using solar energy to heat an intermediate absorbing material. In our work, we are designing an absorber that will emit a narrow band of thermal radiation using 3D metallic photonic crystals.
The narrow band emission should be tailored to match the band gap of the final solar cell material. In doing this, many of the loss mechanisms in a conventional solar cell can be avoided. Thus, the theoretical efficiency of TPV cells increases to 85% (as compared to approximately 30% for a conventional solar cell).
Our research will focus on the fabrication of tungsten photonic crystals to be used as the absorbing/emitting material for a TPV cell. Simulations of ideal structures calculated by a collaborator will be experimentally realized using either chemical vapor deposition or molten salt electrodeposition.
[1] Lin, Moreno, Fleming, Applied Phys. Letters 83, 380 (2003).
[2] Raphaeli and Shin, Applied Phys. Letters 92, 211107 (2008).
Enhancing Absorption in Dye Sensitized Solar Cells coupled to Photonic Crystals
Collaborators: Dr. Agustin Mihi (Braun Group)
Josh Ritchey (Moore Group, UIUC)
The dye sensitized (DSSC) solar cell is an attractive, low cost, alternative to the traditional solid state solar cell. However, DSSC’s suffer from lower efficiencies and long term stability problems. Efficiency problems arise from charge recombination/transport problems and low optical density inside the cell.
DSSC Operation [1]
The optical density issue can be addressed by the use of photonic crystals. Our work involves replacing the tradition nanocrystalline TiO2 layer with a TiO2 inverse opal photonic crystal. This idea of coupling a photonic crystal to a DSSC for enhanced absorption has been explored before2. However, our project differs from previous work because we will be utilizing frequencies of light within the high energy bands of the photonic crystal.
[1] Gratzel, Nature 353 (1991).
[2] Mihi and Miguez, J. Phys. Chem. B. 109, 15968 (2005).
Professor Paul Braun • Phone: +1.217.244.7293 • Fax: +1.217.333.2736 • Email: pbraun@illinois.edu
Department of Materials Science and Engineering • University of Illinois at Urbana-Champaign