Dual-Mechanism Enhancement in Ultrathin CIGS Solar Cells via Secondary Absorber and Passivated Layer Integration

Jafari, Seyed Mohammad Hosein; Dorostkar Yaghouti, Behnam

doi:10.22075/mseee.2026.41867.1291

Dual-Mechanism Enhancement in Ultrathin CIGS Solar Cells via Secondary Absorber and Passivated Layer Integration

Articles in Press

Document Type : Research Article

Authors

Seyed Mohammad Hosein Jafari ¹

Behnam Dorostkar Yaghouti ²

¹ Faculty of Electrical and Computer Engineering, Semnan University, Iran.

² Amin University, Isfahan, Iran.

10.22075/mseee.2026.41867.1291

Abstract

This study investigates the combined influence of a rear passivation layer and a secondary absorber on the performance of ultrathin CIGS solar cells through numerical simulations. Three potential secondary absorber materials—CIS, GaAs, and CGS—were systematically examined to assess their impact on device behavior. The results show that the incorporation of CIS leads to performance degradation, mainly due to enhanced rear-interface recombination. In contrast, both GaAs and CGS noticeably improve the device efficiency. The optimal configuration was achieved using a 0.2 μm CGS layer beneath a 0.8 μm CIGS absorber, which increased the power conversion efficiency from 19.77% to 25.5%. This improvement is primarily attributed to favorable band alignment, the formation of an effective back-surface field, and a strong reduction in rear-interface recombination losses. Although electric-field analysis revealed that GaAs generates a higher field peak at the rear interface, CGS offers superior band matching and interface quality, ultimately resulting in better overall device performance. These findings highlight that the combination of rear passivation with CGS as a secondary absorber is a promising strategy for suppressing recombination and enhancing the efficiency of ultrathin CIGS solar cells.

Keywords

Index Terms- CIGS solar cell

solar cell efficiency

rear passivation

Cd-free CIGS solar cell

Subjects

Electronics

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