Veröffentlichungen
2019 |
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C. Hollemann, F. Haase, S. Schäfer, J. Krügener, R. Brendel, and R. Peibst 26.1%-efficient POLO-IBC cells: Quantification of electrical and optical loss mechanisms Artikel Progress in Photovoltaics: Research and Applications 27 (11), 950-958, (2019). Abstract | Links | BibTeX | Schlagwörter: efficiency potential, IBC solar cells, lifetime monitoring, passivating contacts, POLO @article{Hollemann2019,
title = {26.1%-efficient POLO-IBC cells: Quantification of electrical and optical loss mechanisms}, author = {C Hollemann and F Haase and S Schäfer and J Krügener and R Brendel and R Peibst}, doi = {10.1002/pip.3098}, year = {2019}, date = {2019-11-01}, journal = {Progress in Photovoltaics: Research and Applications}, volume = {27}, number = {11}, pages = {950-958}, abstract = {Abstract We present experimental results for interdigitated back contacted (IBC) solar cells with passivating POLO contacts for both polarities with a nominal intrinsic poly-Si region between them. We reach efficiencies of 26.1% and 24.9% on a 1.3 Ω cm and 80 Ω cm p-type FZ wafer and 24.6% on a 2 Ω cm n-type Cz wafer, respectively. The initially measured implied efficiency potentials of the cells after passivating the surfaces are very similar, namely, 26.8%, 26.8%, and 26.4%, respectively. We attribute the difference between the efficiency potential and the final current-voltage measurement to degradation, perimeter, and series and shunt resistance losses, which we quantify by lifetime measurements. With these measurements in combination with a finite element simulation, we determine the surface recombination velocity in the nominal intrinsic poly-Si region to be in the range from 13 to 21 cm s−1. Using the same approach, we analyze the increase of the front surface recombination velocity during cell processing from 2 to 10 cm s−1 for the 1.3 Ω cm and from 0.5 to 2.3 cm s−1 for the 80 Ω cm. This leads to the fact that cells fabricated on lowly doped bulk material are more vulnerable to a process-induced degradation of the surface passivation quality. We further determine the theoretical limits of the cells by firstly idealizing the recombination (28% for 1.3 Ω cm and 28.2% for 80 Ω cm) and secondly also idealizing the optics of the solar cells (29.4% and 29.5%).}, keywords = {efficiency potential, IBC solar cells, lifetime monitoring, passivating contacts, POLO}, pubstate = {published}, tppubtype = {article} } Abstract We present experimental results for interdigitated back contacted (IBC) solar cells with passivating POLO contacts for both polarities with a nominal intrinsic poly-Si region between them. We reach efficiencies of 26.1% and 24.9% on a 1.3 Ω cm and 80 Ω cm p-type FZ wafer and 24.6% on a 2 Ω cm n-type Cz wafer, respectively. The initially measured implied efficiency potentials of the cells after passivating the surfaces are very similar, namely, 26.8%, 26.8%, and 26.4%, respectively. We attribute the difference between the efficiency potential and the final current-voltage measurement to degradation, perimeter, and series and shunt resistance losses, which we quantify by lifetime measurements. With these measurements in combination with a finite element simulation, we determine the surface recombination velocity in the nominal intrinsic poly-Si region to be in the range from 13 to 21 cm s−1. Using the same approach, we analyze the increase of the front surface recombination velocity during cell processing from 2 to 10 cm s−1 for the 1.3 Ω cm and from 0.5 to 2.3 cm s−1 for the 80 Ω cm. This leads to the fact that cells fabricated on lowly doped bulk material are more vulnerable to a process-induced degradation of the surface passivation quality. We further determine the theoretical limits of the cells by firstly idealizing the recombination (28% for 1.3 Ω cm and 28.2% for 80 Ω cm) and secondly also idealizing the optics of the solar cells (29.4% and 29.5%).
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