| Loss Factors and
Efficiency
of Semiconductor |
| Makoto Imai |
| Photovoltaic electricity could be produced at a cost of $0.031 ~ 0.039kWh |
| if efficiencies of 45 % were ever achieved | |
| Solar cell |
| System must | |||
| Be low cost | |||
| Have long operation time | |||
| Have high solar-to-chemical conversion efficiency | |||
| Loss factor in plants |
| 2 % solar to energy conversion efficiency |
| Major loss factors in semiconductor |
| Optical – collection of light | |
| Wavelength match – not absorbed | |
| – heat loss | |
| Junction loss | |
| Curve factor | |
| Recombination | |
| Curve factor A loss | |
| Series resistance | |
| Reflection loss | |
| Loss factor in silicon cell |
| Minimizing two major loss factor |
| Long wavelength photons not absorbed | ||
| Antireflection | ||
| Wavelength match | ||
| Heat loss | ||
| Wavelength match | ||
| Multiple band gap cell |
| Multiple band gap structure |
| Multiple band gap cell (experiment) |
| Multiple band gap cell quantum efficiency |
| Energy Gap |
| Fig. PVCM2: Band Gap Energies at 25C. Units are electron volts (eV). |
| Amorphous silicon |
| Advantage | ||
| Cheap process | ||
| Higher band gap | ||
| Future research |
| Stabilizing multi-band gap | |
| Stabilizing tunnel |
| Article about growing multi-band gap |
| Bertness KA, Friedman, DJ, Kibbler AE, Kramer C, kurtz SR, Olson JM. 12th NREL Photovoltaic Program Review Meeting. Denver, CO, 1993, p. 100 | |
| Olson JM, Kurtz SR. US Patent No. 5,223, 043 |