Microwave-Assisted Synthesis of Few-Layer Black Phosphorus and Its Application in Solar Cells

Author:

Bat-Erdene, Munkhjargal, 2017 Microwave-Assisted Synthesis of Few-Layer Black Phosphorus and Its Application in Solar Cells, Flinders University, School of Chemical and Physical Sciences

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Abstract

Breakthroughs in materials science will undoubtedly have a significant impact on the future development of technology since the research into nanostructured materials is currently playing a central role in the revolutionary technologies. Since the discovery of graphene, two-dimensional (2D) materials have emerged as important advanced materials due to their unique structures and fascinating properties. Phosphorene – few-layer black phosphorus (BP) – has been introduced as a new member to the family of elemental 2D layered materials. Phosphorene is attracting tremendous interest from the scientific community and has shown great promise in a diverse range of applications owing to its unique structure and excellent properties. One of the most promising applications for phosphorene and phosphorene based materials is photovoltaic (PV). However, the limited number of established experimental procedures to prepare phosphorene restricts its successful application in solar cells. Therefore simple production of high quality, stable and scalable 2D phosphorene sheets is extremely challenging. In this project, we demonstrated a facile, novel and efficient way to prepare solution processable phosphorene flakes in N-methyl-2-pyrrolidone (NMP) solvent using a microwave (MW)-assisted method in ambient conditions. The as-prepared phosphorene flakes were highly crystalline, atomically thin and exhibit low oxidation level in ambient condition. More importantly, this MW-assisted liquid-phase exfoliation method requires a very short processing time (~10 min) and does not involve the use of any surfactant or ultrasonication to obtain stable phosphorene dispersion. As a proof of concept, our MW-exfoliated phosphorene sheets were introduced into single-walled carbon nanotube-silicon (SWCNT-Si) heterojunction solar cells (HJSCs) for the first time. The NMP based phosphorene sheets remain stable after mixing with water based SWCNT dispersion for device fabrication. Because of their unique structure and p-type dominated conduction, the phosphorene sheets incorporated SWCNT-Si solar cells exhibited remarkably high power conversion efficiency (PCE) of 9.37%, whereas the control device fabricated without phosphorene showed a PCE of 7.52%. We carried out a wide range of experimental analysis, combined with theoretical density-functional theory (DFT) calculation, to provide a molecular level understanding of the influence of phosphorene sheets in SWCNT-Si solar cells. Overall, this Master’s project is extremely important in that it has the potential to facilitate future development of phosphorene research.

Keywords: Materials Science, Nanotechnology, 2D materials, Solar Cells, Phosphorene, Black Phosphorus, Microwave Chemistry, Liquid-Phase Exfoliation
Subject: Chemistry thesis, Physics thesis

Thesis type: Masters
Completed: 2017
School: School of Chemical and Physical Sciences
Supervisor: Joe Shapter