Atom Substitution Defects of Hexagonal Boron Phosphide Suppress Charge Recombination

Lili Xu; Aolei Wang; Bingwen Li; Jin Zhao; Haibo Zeng; Shengli Zhang

doi:10.1021/acs.jpclett.2c01882

Atom Substitution Defects of Hexagonal Boron Phosphide Suppress Charge Recombination

J Phys Chem Lett. 2022 Jul 21;13(28):6455-6461. doi: 10.1021/acs.jpclett.2c01882. Epub 2022 Jul 11.

Authors

Lili Xu¹, Aolei Wang², Bingwen Li³, Jin Zhao², Haibo Zeng¹, Shengli Zhang¹

Affiliations

¹ MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China.
² ICQD/Hefei National Laboratory for Physical Sciences at Microscale, and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei 230026, Anhui, China.
³ Shandong Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, Shandong, China.

PMID: 35816281
DOI: 10.1021/acs.jpclett.2c01882

Abstract

Point defects, during e-h recombination, are a key factor in impacting optoelectronic device performance. Using nonadiabatic molecular dynamics (NAMD), here we investigate the nonradiative recombination of pristine, missing atom defects, including phosphorus vacancies (V_P) and phosphorus and boron vacancies (V_BP), and atom substitution defects, containing boron on the phosphorus site (B_P) and phosphorus on the boron site (P_B) of 2D monolayer hexagonal boron phosphide (h-BP). Carrier dynamics in the pristine h-BP and the defect engineered systems reveal that atom substitution defects B_P and P_B can suppress e-h nonradiative recombination. This is caused by the introduction of several low-frequency phonons in defect states. Electron-phonon coupling between the electronic state and these low-frequency phonons shortens the decoherence time and the nonadiabatic coupling. Also, the atom substitution systems with one defect state introduce fewer carrier recombination channels. Such a mechanism can be extended to other 2D materials with the same structure as h-BP.