| Autor: |
Avancini, Enrico, Keller, Debora, Carron, Romain, Arroyo-Rojas Dasilva, Yadira, Erni, Rolf, Priebe, Agnieszka, Di Napoli, Simone, Carrisi, Martina, Sozzi, Giovanna, Menozzi, Roberto, Fu, Fan, Buecheler, Stephan, Tiwari, Ayodhya N. |
| Předmět: |
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| Zdroj: |
Science & Technology of Advanced Materials; Dec2018, Vol. 19 Issue 1, p871-882, 12p |
| Abstrakt: |
Structural defects such as voids and compositional inhomogeneities may affect the performance of Cu(In,Ga)Se2 (CIGS) solar cells. We analyzed the morphology and elemental distributions in co-evaporated CIGS thin films at the different stages of the CIGS growth by energy-dispersive x-ray spectroscopy in a transmission electron microscope. Accumulation of Cu-Se phases was found at crevices and at grain boundaries after the Cu-rich intermediate stage of the CIGS deposition sequence. It was found, that voids are caused by Cu out-diffusion from crevices and GBs during the final deposition stage. The Cu inhomogeneities lead to non-uniform diffusivities of In and Ga, resulting in lateral inhomogeneities of the In and Ga distribution. Two and three-dimensional simulations were used to investigate the impact of the inhomogeneities and voids on the solar cell performance. A significant impact of voids was found, indicating that the unpassivated voids reduce the open-circuit voltage and fill factor due to the introduction of free surfaces with high recombination velocities close to the CIGS/CdS junction. We thus suggest that voids, and possibly inhomogeneities, limit the efficiency of solar cells based on three-stage co-evaporated CIGS thin films. Passivation of the voids' internal surface may reduce their detrimental effects. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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