Tuning electronic and optical properties of graphene quantum dots via silicon doping for photovoltaic applications

Authors

• Sunidhi Punia, Guru Jambheshwar University of Science & Technology
• Hardev S. Saini, Guru Jambheshwar University of Science & Technology
• Anuj Damara, Jawaharlal Nehru University
• Kiran Chahal, Guru Jambheshwar University of Science & Technology
• Priya Rani, Baijnath Choudhary Government College for Women
• Rajesh Kumar, Guru Jambheshwar University of Science & Technology
• Manish K. Kashyap, Jawaharlal Nehru University
• Ravindra Pandey, Michigan Technological UniversityFollow

Document Type

Article

Publication Date

6-2026

Department

Department of Physics

Abstract

A theoretical study on how silicon doping influences the optoelectronic properties of GQDs, simulated with zigzag (C24H12) and armchair (C42H18) configurations, is performed using time-dependent density functional theory. Analysis of the electron density isosurfaces indicates that Si doping induces a hybridization of σ and π bond orbitals, leading to a significant reduction in the HOMO–LUMO energy gap. Charge-density difference and transition-density-matrix analyses indicate that excited states are mainly characterized by charge-transfer transitions, which facilitate exciton formation. The absorption spectra of pristine and Si-doped zigzag QDs fall within the range of 400–600 nm, whereas for the armchair GQD, it shifts to 500–700 nm. This broad visible-light absorption and tunable bandgap suggest that Si-GQDs are highly promising for use in photovoltaic applications.

Publication Title

Diamond and Related Materials

Recommended Citation

Punia, S., Saini, H., Damara, A., Chahal, K., Rani, P., Kumar, R., Kashyap, M., & Pandey, R. (2026). Tuning electronic and optical properties of graphene quantum dots via silicon doping for photovoltaic applications. Diamond and Related Materials, 166. http://doi.org/10.1016/j.diamond.2026.113774
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p2/2625