Fabrication and analysis of record high 18.2% efficient solar cells on multicrystalline silicon material
- Georgia Inst. of Tech., Atlanta, GA (United States). Univ. Center of Excellence in Photovoltaic Research and Education
- Crystal Systems, Inc., Salem, MA (United States)
Solar cell efficiencies of 18.2% (1 cm{sup 2} areas) have been achieved using a process sequence which involves impurity gettering on 0.65 {Omega}-cm multicrystalline silicon (mc-Si) grown by the heat exchanger method (HEM). This represents the highest reported solar cell efficiency on mc-Si to date. Photoconductive decay (PCD) measurements were used to monitor the lifetime in control samples which underwent the same process sequence as solar cells. PCD analysis reveals that HEM mc-Si material with an average as-grown bulk lifetime ({tau}{sub b}) of 12 {micro}s can achieve a lifetime as high as 135 {micro}s by process-induced gettering. Internal quantum efficiency (IQE) measurements reveal that the effective diffusion length (L{sub eff}) in the finished devices is 244 {micro}m (or close to 90% of the total device width). Detailed cell analysis shows that for this combination of {tau}{sub b} and L{sub eff}, the back surface recombination velocity (S{sub b}) of 10,000 cm/s or higher is the dominant efficiency limiting factor in the uniform regions of these mc-Si devices. Lowering S{sub b} can raise the efficiency of untextured HEM mc-Si solar cells above 19.0%, thus closing the efficiency gap between good quality, untextured single crystal and mc-Si solar cells.
- OSTI ID:
- 282393
- Journal Information:
- IEEE Electron Device Letters, Journal Name: IEEE Electron Device Letters Journal Issue: 8 Vol. 17; ISSN 0741-3106; ISSN EDLEDZ
- Country of Publication:
- United States
- Language:
- English
Similar Records
Gettering and passivation of high efficiency multicrystalline silicon solar cells
18.2% efficient multicrystalline silicon cell