Citation

Rajesh, K. and Harikrishnan, P. and Sivakumar, S. and You, Ah Heng and Wong, Wai Kit and Ng, Poh Kiat (2026) A next-generation Cd-free CIGS solar cell enabled by ZnMgO window engineering and Al2O3 interface passivation. Energy Reports, 16. p. 109570. ISSN 23524847

Text A next-generation Cd-free CIGS solar cell enabled by ZnMgO window engineering and Al2O3 interface passivation.pdf - Published Version Restricted to Repository staff only Download (7MB)

Abstract

This paper presents a next-generation Cd-free Cu(In,Ga)Se₂ (CIGS) solar cell architecture incorporating a widebandgap ZnMgO window layer, an ultrathin Al₂O₃ passivation layer, and an S-rich Zn(O,S) buffer layer to enhance band alignment, suppress interface recombination, and improve photovoltaic performance. The proposed ZnMgO/Al₂O₃/Zn(O,S)/CIGS device was numerically investigated using Technology Computer-Aided Design (TCAD) integrated with the optical Transfer Matrix Method (TMM) to evaluate its electrical and optical characteristics. Device performance was benchmarked against a literature-calibrated reference simulation based on previously reported parameters to assess the effectiveness of the proposed interface engineering strategy. Simulation results demonstrate significant performance enhancement compared with the reference structure. The optimized device achieves a short-circuit current density (JSC) of 38.67 mA/cm², while the opencircuit voltage (VOC) increases from approximately 0.50 V to 0.71 V owing to improved interface quality and reduced carrier recombination introduced by the Al₂O₃ passivation layer. Furthermore, the device attains a fill factor (FF) of approximately 0.75, resulting in a maximum output power density of 15–16 mW/cm² and a power conversion efficiency (PCE) approaching 20–21%. These improvements are attributed to enhanced carrier collection efficiency, favorable energy band alignment, and effective suppression of interface recombination at the buffer/absorber junction. Optical analysis further confirms improved light transmission through the ZnMgO window layer and enhanced photon absorption within the CIGS absorber, leading to increased photogenerated carrier generation throughout the active region. The simulated external quantum efficiency (EQE) remains below the theoretical limit of 100% while exhibiting enhanced spectral response across the visible wavelength range. Overall, the proposed ZnMgO/Al₂O₃ interface-engineered CIGS solar cell demonstrates superior electrical and optical performance compared with conventional Cd-based structures, providing a promising pathway toward environmentally friendly, cadmium-free, and high-efficiency thin-film photovoltaic technologies.

Item Type:	Article
Uncontrolled Keywords:	Cd-Free CIGS Solar Cell, ZnMgO Window Engineering
Subjects:	T Technology > TK Electrical engineering. Electronics Nuclear engineering > TK9900-9971 Electricity for amateurs. Amateur constructors' manuals
Divisions:	Faculty of Engineering and Technology (FET)
Depositing User:	Ms Rosnani Abd Wahab
Date Deposited:	02 Sep 2026 06:18
Last Modified:	02 Sep 2026 06:18
URII:	http://shdl.mmu.edu.my/id/eprint/16528

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