Details
| Original language | English |
|---|---|
| Article number | 2202076 |
| Journal | Advanced energy materials |
| Volume | 12 |
| Issue number | 44 |
| Early online date | 22 Sept 2022 |
| Publication status | Published - 24 Nov 2022 |
Abstract
To achieve a high fill factor, a small diode factor close to 1 is essential. The optical diode factor determined by photoluminescence is the diode factor from the neutral zone of the solar cell and thus a lower bound for the diode factor. Due to metastable defects transitions, the optical diode factor is higher than 1 even at low excitation. Here, the influence of the backside recombination and the doping level on the optical diode factor are studied. First, photoluminescence and solar cell capacitance simulator (SCAPS) simulations are used to determine the back surface recombination velocity of Cu(In, Ga)Se2 with various back contacts and different doping levels. Then, experimental results and simulations show that both back surface recombination and high doping density reduce the optical diode factor. The back surface recombination reduces the optical diode factor with undesirable extra nonradiative recombination. The smaller value achieved by higher doping can increase quasi-Fermi level splitting at the same time. The simulations show that the back surface recombination reduces the optical diode factor due to an illumination-dependent recombination rate. In addition, a higher majority carrier doping reduces the influence of majority carrier gain from metastable defect transitions, thus reducing the optical diode factor.
Keywords
- back contacts, CIGSe, optical diode factor, photoluminescence
ASJC Scopus subject areas
Sustainable Development Goals
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In: Advanced energy materials, Vol. 12, No. 44, 2202076, 24.11.2022.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Diode Factor in Solar Cells with Metastable Defects and Back Contact Recombination
AU - Wang, Taowen
AU - Ehre, Florian
AU - Weiss, Thomas Paul
AU - Veith-Wolf, Boris
AU - Titova, Valeriya
AU - Valle, Nathalie
AU - Melchiorre, Michele
AU - Ramírez, Omar
AU - Schmidt, Jan
AU - Siebentritt, Susanne
N1 - Funding Information: This work was supported by the Luxembourg National Research Fund (FNR) through the PACE project under the grant number PRIDE17/12246511/PACE and through the SeVac project (C17/MS/11655733/SeVac) and the GRISC project (C17/MS/11696002 GRISC). The authors thank all developers of SCAPS at the department of Electronics and Information Systems (ELIS) of the University of Gent. Brahime El Adib is thanked for his technical assistance for SIMS measurements performed within the Advanced Characterization Platform (LIST). For the purpose of open access, the author has applied a Creative Commons Attribution 4.0 International (CC BY 4.0) license to any Author Accepted Manuscript version arising from this submission.
PY - 2022/11/24
Y1 - 2022/11/24
N2 - To achieve a high fill factor, a small diode factor close to 1 is essential. The optical diode factor determined by photoluminescence is the diode factor from the neutral zone of the solar cell and thus a lower bound for the diode factor. Due to metastable defects transitions, the optical diode factor is higher than 1 even at low excitation. Here, the influence of the backside recombination and the doping level on the optical diode factor are studied. First, photoluminescence and solar cell capacitance simulator (SCAPS) simulations are used to determine the back surface recombination velocity of Cu(In, Ga)Se2 with various back contacts and different doping levels. Then, experimental results and simulations show that both back surface recombination and high doping density reduce the optical diode factor. The back surface recombination reduces the optical diode factor with undesirable extra nonradiative recombination. The smaller value achieved by higher doping can increase quasi-Fermi level splitting at the same time. The simulations show that the back surface recombination reduces the optical diode factor due to an illumination-dependent recombination rate. In addition, a higher majority carrier doping reduces the influence of majority carrier gain from metastable defect transitions, thus reducing the optical diode factor.
AB - To achieve a high fill factor, a small diode factor close to 1 is essential. The optical diode factor determined by photoluminescence is the diode factor from the neutral zone of the solar cell and thus a lower bound for the diode factor. Due to metastable defects transitions, the optical diode factor is higher than 1 even at low excitation. Here, the influence of the backside recombination and the doping level on the optical diode factor are studied. First, photoluminescence and solar cell capacitance simulator (SCAPS) simulations are used to determine the back surface recombination velocity of Cu(In, Ga)Se2 with various back contacts and different doping levels. Then, experimental results and simulations show that both back surface recombination and high doping density reduce the optical diode factor. The back surface recombination reduces the optical diode factor with undesirable extra nonradiative recombination. The smaller value achieved by higher doping can increase quasi-Fermi level splitting at the same time. The simulations show that the back surface recombination reduces the optical diode factor due to an illumination-dependent recombination rate. In addition, a higher majority carrier doping reduces the influence of majority carrier gain from metastable defect transitions, thus reducing the optical diode factor.
KW - back contacts
KW - CIGSe
KW - optical diode factor
KW - photoluminescence
UR - http://www.scopus.com/inward/record.url?scp=85138507762&partnerID=8YFLogxK
U2 - 10.1002/aenm.202202076
DO - 10.1002/aenm.202202076
M3 - Article
AN - SCOPUS:85138507762
VL - 12
JO - Advanced energy materials
JF - Advanced energy materials
SN - 1614-6832
IS - 44
M1 - 2202076
ER -