Micromorph
The
The micromorph cell
Micromorph cells are
Since the bandgaps of amorphous silicon (1.7 eV) and microcrystalline Silicon (1.1 eV) are well suited for tandem solar cells, the
The advantage of the micromorph approach is that it keeps the thickness of the amorphous top cell low. This reduces the effect of degradation induced by light (
The intermediate reflector
The intermediate reflector is a layer (IRL) of zinc oxide (ZnO intermediate reflector: ZIR) or silicon oxide (SiOx intermediate reflector: SOIR) between the top and the bottom cell. Due to its lower refractive index of around 2 comparing to the surrounding silicon (4) light is reflected back into the top cell. This increases the top cell current from around 10 mA/cm2 to 12 mA/cm2, but reduces the bottom cell current by an equal amount.
The word micromorph
This artificial word was first mentioned in a scientific publication of the
Years later, other European, Japanese and American research groups started research activities in the field of improving the conversion efficiency of thin-film silicon solar cells by utilizing the stacked solar cell concept, naming the micromorph device 'hybrid' solar cell or naming the microcrystalline silicon absorber 'nanocrystalline' or even 'policrystalline' silicon.
The word 'micromorph' has been lately claimed to belong to an equipment manufacturer of silicon coating tools, but in a patent judgement, this claim has not been accepted by European patent offices.[2]
See also
- TEL Solar (former Oerlikon solar)
External links
- Presentation with informative pictures and current state of industrial production: http://www.swisslaser.net/libraries.files/UlrichKrollOerlikon.pdf
References
- ^ J. Meier, S. Dubail, D. Fischer, J. A. Anna Selvan, N. Pellaton Vaucher, R. Platz, C. Hof, R. Flückiger, U. Kroll, N. Wyrsch, P. Torres, H. Keppner, A. Shah, K.-D. Ufert, "The 'Micromorph' Solar Cells: a New Way to High Efficiency Thin Film Silicon Solar Cells", Proceedings of the 13th EC Photovoltaic Solar Energy Conference, Nice, October 1995, pp. 1445–1450.
- ^ O. Papathanasiou, "A good day for Ms. Schönefeld-Schnuck PI 5/2009 page 44", http://www.op-solar.de/pdfs/A%20good%20day%20for%20Schoenefeld-Schnuck.pdf