Optoelectronic Properties of Nitrogen-Doped Hexagonal Graphene Quantum Dots: A First-Principles Study

Pham Vu Nhat; Nguyen Vo Anh Duy; Thi Nhan Tran; Nguyen Thanh Si; Truc Anh Nguyen; Nguyen To Van; Nguyen Van Nghia; Peter Schall; Van An Dinh; Minh Triet Dang

doi:10.1021/acsomega.3c10501

Optoelectronic Properties of Nitrogen-Doped Hexagonal Graphene Quantum Dots: A First-Principles Study

ACS Omega. 2024 Apr 24;9(18):20056-20065. doi: 10.1021/acsomega.3c10501. eCollection 2024 May 7.

Authors

Affiliations

¹ Can Tho University, 3-2 Road, Can Tho 900000, Vietnam.
² FPT University, Can Tho Campus, 600 Nguyen Van Cu Street, Ninh Kieu, Can Tho 900000, Vietnam.
³ Faculty of Fundamental Sciences, Hanoi University of Industry, 298 Cau Dien Road, Hanoi 100000, Vietnam.
⁴ Institute of Environmental Science and Technology, Tra Vinh University, Tra Vinh 94000, Vietnam.
⁵ Faculty of Mechanics, Can Tho University of Technology, 256 Nguyen Van Cu Street, Can Tho 900000, Vietnam.
⁶ Faculty of Chemico-Physical Engineering, Le Quy Don Technical University, Ha Noi 100000, Vietnam.
⁷ Open Training Institute, Hanoi Architectural University, Km10, Nguyen Trai Street, Hanoi 100000, Vietnam.
⁸ Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands.
⁹ Department of Precision Engineering, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.

Abstract

Graphene quantum dots have been widely studied owing to their unique optical, electrical, and optoelectrical properties for various applications in solar devices. Here, we investigate the optoelectronic properties of hexagonal and nitrogen-doped graphene quantum dots using the first-principles method. We find that doping nitrogen atoms to hexagonal graphene quantum dots results in a significant red shift toward the visible light range as compared to that of the pristine graphene quantum dots, and the doped nitrogen atoms also induce a clear signature of anisotropy of the frontier orbitals induced by the electron correlation between the doped nitrogen atoms and their adjacent carbon atoms. Moreover, time-dependent density functional theory calculations with the M06-2X functional and 6-311++G(d,p) basis set reproduce well the experimental absorption spectra reported recently. These results provide us with a novel approach for more systematic investigations on next-generation solar devices with assembled quantum dots to improve their light selectivity as well as efficiency.