Optimization of Back Contact Grid Size in Al2O3-Rear-Passivated Ultrathin CIGS PV Cells by 2-D Simulations
| Main Authors: | Jackson Lontchi, Maria Zhukova, Milan Kovacic, Janez Krc, Wei-Chao Chen, Marika Edoff, Sourav Bose, Pedro M. P. Salomé, Julie Goffard, Andrea Cattoni, L. Gouillart, Stephane Collin, Viktoria Gusak, Denis Flandre |
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| Format: | info publication-preprint Journal |
| Terbitan: |
, 2020
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| Online Access: |
https://zenodo.org/record/4479298 |
Daftar Isi:
- We present a simulation strategy using ATLAS-2D too optimize the back-contact hole grid (i.e., size and pitch of openings)of the Al2O3-rear-passivation layer in ultrathin Cu(In,Ga)Se2pho-tovoltaic cells. We first discuss and compare our simulation model with a series of experimental non passivated and passivated cells to decouple the crucial passivation parameters. The simulation results follow the experimental trends, highlighting the beneficial effects of the passivation on the cell performances. Furthermore, it stresses the influence of the passivation quality at the Al2O3/Cu(In,Ga)Se2(CIGS) interface and of the contact resistance at the Mo/CIGS interface within the openings. Further simulations quantify significant improvements in short-circuit current and open-circuit volt-age for different sizes of openings in the Al2O3layer, relative to an excellent passivation quality (i.e., high density of negative charges in the passivation layer). However, a degradation is predicted for a poor passivation (i.e., low density of such charges) or a high contact resistance. Consequently, we point out an optimum in efficiency when varying the opening widths at fixed hole-pitch and fixed contact resistance. At equivalent contact resistance, simulations predict that the sizes of the pitch and openings can be increased without optimal performance losses when maintaining a width to pitch ratio around 0.2. This simulation trends have been confirmed by a series of experiments, indicating that it is crucial to care about the dimensions of the opening grid and the contact resistance of passivated cells. These simulation results provide significant insights for optimal cell design and characterizations of passivated UT-CIGS PV cells.