Ruland, Andres, Schulz-Drost, Christian, Sgobba, Vito, and Guldi, Dirk M. (2011). "Enhancing Photocurrent Efficiencies by Resonance Energy Transfer in CdTe Quantum Dot Multilayers: Towards Rainbow Solar Cells" in Advanced Materials.
Motivation of the paper:
- want a "low-cost, easily producible, and efficient" solar cell
- because current designs are not yet commercially viable, these researchers are trying to find a solution
- they decided to jump on the quantum dot (nanocrystal) bandwagon
The authors demonstrate the use of Forster resonant energy transfer (FRET) in collecting sunlight at different layers of CdTe quantum dots. The problem with this design, however, is that it is a quantum dot multijunction solar cell in its most primitive form, which they admit in the conclusion. It is simply layer-by-layer (LbL) deposited quantum dots, one atop another four times, instead of in some sort of substrate - like silicon. Thus, while these researchers claim a 25% increase in solar efficiency, and while they experimentally demonstrate the applicability of these quantum dots as light harvesters, they ultimately must conclude that "the net power conversion efficiency of these photocathodes is significantly lower than those typically seen in dye-sensitized solar cells or organic solar cells," essentially claiming that their work proves concepts and helps a little, but the technology still needs a lot of work.
How this relates to my work:
More motivation for me (the researchers are calling attention to this high-potential new field that has some interesting barriers before it becomes commercially competitive). Relates to Gimenez et. al. in experimental technique (in situ), which I may ultimately treat as a control of sorts (i.e. deposition technique has variously been confirmed to be in situ for optimal solar absorption).
I think I have found a way to theoretically model Kamat's problem about synergistic effect in multijunction (quantum dot) solar cells. This FRET phenomenon that Ruland et. al. uses basically describes, energetically, the interactions between quantum dot layers. It is not one-size-fits-all (there is always a catch) - FRET is only energy transfer, which is only downwards in the cell (i.e. top layer absorbs some sunlight, filters through to second layer which absorbs some different wavelengths from the first, and so on). Ruland et. al. mentions reversibility (which would be FRET and anti-FRET) but then this would only be bottom-up versus top-bottom.
So my contribution might incorporate a universal FRET, one that describes the interactions of any two quantum dot layers at a time. My simulations would then have much higher versatility, such as the capability of adding layers on top and bottom at will without upsetting the energy transfer model.
Thank you for reading!