Bandgap engineering of CuGaS2–CuInS2 heterostructures for efficient thin-film photovoltaics
10 affiliations
- 1Department of Physics, College of Science, University of Ha'il P.O. Box 2440 Ha'il Saudi Arabia
- 2Faculty of Electrical Technology and Engineering, Universiti Teknikal Malaysia Melaka Melaka Malaysia
- 3International Center for Interdisciplinary Research in Sciences (ICIRS), The University of Lahore Lahore 54000 Pakistan
- 4School of Quantitative Sciences, UUM College of Arts & Sciences, Universiti Utara Malaysia Darul Aman Sintok Kedah 06010 Malaysia
- 5Department of Industrial and Systems Engineering, College of Engineering, Princess Nourah bint Abdulrahman University P. O. Box 84428 Riyadh 11671 Saudi Arabia
- 6Department of Physical Sciences, College of Science, University of Jeddah Jeddah 23890 Saudi Arabia
- 7Department of Mechanical Engineering, College of Engineering at Yanbu, Taibah University Yanbu Al-Bahr 41911 Saudi Arabia
- 8Energy, Industry, and Advanced Technologies Research Center, Taibah University Madinah Saudi Arabia
- 9Department of Electrical Engineering, College of Engineering, Al-Baha University P.O. Box 65799 Albaha Saudi Arabia
- 10Department of Physics, College of Science, Qassim University Buraidah 51452 Saudi Arabia
Abstract
Developing efficient and affordable thin-film solar cells requires absorber materials that can harvest a broad portion of sunlight while minimizing charge-carrier losses. Here, a CuGaS2–CuInS2 heterostructure was developed as an absorber to improve the optical and interfacial properties of CuInS2-based photovoltaic devices. X-ray diffraction confirmed the coexistence of the constituent chalcopyrite phases, with the heterostructure exhibiting an average crystallite size of 39.4 nm and a (112) d-spacing of 3.226 Å. SEM and HR-TEM revealed interconnected morphology, intimate interfacial contact, and well-resolved lattice fringes. UV-visible analysis showed that heterostructure formation reduced the optical bandgap from 1.74 eV for CuInS2 to 1.64 eV, extending visible-light absorption. The FTO/TiO2/CuGaS2–CuInS2/Spiro-OMeTAD/Au device achieved a power conversion efficiency of 7.41% with a fill factor of 0.632, compared with 5.09% and 0.485, respectively, for the CuInS2 device. Electrochemical impedance spectroscopy showed a lower charge-transfer resistance of 14.22 Ω and a higher recombination resistance of 2919.9 Ω, while the maximum external quantum efficiency increased from approximately 79% to 86%. These findings demonstrate that heterostructure engineering provides a practical route for simultaneously tuning light absorption and interfacial carrier transport, offering broader potential for the development of efficient thin-film photovoltaic absorbers.
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BibTeX
@article{bouzidi2026bandgap,
title = {{Bandgap engineering of CuGaS2–CuInS2 heterostructures for efficient thin-film photovoltaics}},
author = {Mohamed Bouzidi and A. F. A. Kadir and Ali Mujtaba and Adnan Asghar and Ghada A. Alsawah and Sultan Albarakati and Ahmed F. Almutairi and Turki Alkathiri and Faisal Alresheedi},
journal = {RSC Advances},
year = {2026},
month = nov,
doi = {10.1039/d6ra07913j},
url = {https://doi.org/10.1039/d6ra07913j},
note = {CC BY-NC 3.0},
}
RIS
TY - JOUR
TI - Bandgap engineering of CuGaS2–CuInS2 heterostructures for efficient thin-film photovoltaics
AU - Mohamed Bouzidi
AU - A. F. A. Kadir
AU - Ali Mujtaba
AU - Adnan Asghar
AU - Ghada A. Alsawah
AU - Sultan Albarakati
AU - Ahmed F. Almutairi
AU - Turki Alkathiri
AU - Faisal Alresheedi
PY - 2026
DA - 2026/11/05
JO - RSC Advances
DO - 10.1039/d6ra07913j
UR - https://doi.org/10.1039/d6ra07913j
AB - Developing efficient and affordable thin-film solar cells requires absorber materials that can harvest a broad portion of sunlight while minimizing charge-carrier losses. Here, a CuGaS2–CuInS2 heterostructure was developed as an absorber to improve the optical and interfacial properties of CuInS2-based photovoltaic devices. X-ray diffraction confirmed the coexistence of the constituent chalcopyrite phases, with the heterostructure exhibiting an average crystallite size of 39.4 nm and a (112) d-spacing of 3.226 Å. SEM and HR-TEM revealed interconnected morphology, intimate interfacial contact, and well-resolved lattice fringes. UV-visible analysis showed that heterostructure formation reduced the optical bandgap from 1.74 eV for CuInS2 to 1.64 eV, extending visible-light absorption. The FTO/TiO2/CuGaS2–CuInS2/Spiro-OMeTAD/Au device achieved a power conversion efficiency of 7.41% with a fill factor of 0.632, compared with 5.09% and 0.485, respectively, for the CuInS2 device. Electrochemical impedance spectroscopy showed a lower charge-transfer resistance of 14.22 Ω and a higher recombination resistance of 2919.9 Ω, while the maximum external quantum efficiency increased from approximately 79% to 86%. These findings demonstrate that heterostructure engineering provides a practical route for simultaneously tuning light absorption and interfacial carrier transport, offering broader potential for the development of efficient thin-film photovoltaic absorbers.
SN - 2046-2069
ER -