Enhancing Visible-Light Absorption of 2D Carbon Nitride by Constructing 2D/2D van der Waals Heterojunctions of Carbon Nitride/Nitrogen-Superdoped Graphene

Yongjie Xu; Maoyun Di; Jiawei Liu; Ziying Li; Yong Wang; Nujiang Tang

doi:10.1021/acsomega.3c08308

Enhancing Visible-Light Absorption of 2D Carbon Nitride by Constructing 2D/2D van der Waals Heterojunctions of Carbon Nitride/Nitrogen-Superdoped Graphene

ACS Omega. 2024 Jan 18;9(4):4804-4810. doi: 10.1021/acsomega.3c08308. eCollection 2024 Jan 30.

Authors

Yongjie Xu¹, Maoyun Di², Jiawei Liu³, Ziying Li³, Yong Wang^{4

5}, Nujiang Tang³

Affiliations

¹ School of Education, Jiangsu Open University, Nanjing 210036, China.
² Laboratory of Magnetic and Electric Functional Materials and the Applications, The Key Laboratory of Shanxi Province, College of Material Science and Technology, Taiyuan University of Science and Technology, Taiyuan 030024, China.
³ National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures and Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University, Nanjing 210093, China.
⁴ Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Academy of Advanced Interdisciplinary Research, Xidian University, Xi'an 710071, China.
⁵ Emerging Device and Chip Laboratory, Hangzhou Institute of Technology, Xidian University, Hangzhou 311200, China.

Abstract

Carbon nitride sheets (CNs) down to the two-dimensional (2D) limit have been widely used in photoelectric conversion due to their inherent band gap and extremely short charge-carrier diffusion distance. However, the utilization of visible light remains low due to the rapid recombination of photogenerated electron-hole pairs and enlarged band gap. Here, atomically thin 2D/2D van der Waals heterojunctions (vdWHs) of N-superdoped graphene (NG) and CNs (CNs/NG) are fabricated via a facile electrostatic self-assembly method. Our results revealed that the vdWHs can increase the visible-light absorption of CNs by extending the absorption edge from 455 to up to 490 nm. The recombination of photogenerated electron-hole pairs is inhibited because superdoped N in CNs/NG facilitates the transmission of photogenerated carriers in the melon chain. This study opens a new avenue for narrowing the band gap and promoting photoexcited carrier separation in carbon-nitride-based materials.