The interfacial chemistry and physics of transition metal chalcogenides and transition metal oxides

Authors: Rosemary Jones (University of Manchester)
Co-authored by industrial partner: No

Type: Thesis

State: Published (Approved)
Published: February 2021

Abstract: This thesis focuses on understanding the fundamental chemistry of metal oxide and chalcogenide interfaces with potential applications to novel photovoltaic devices. Both anatase and rutile TiO2 are commonly used in photovoltaic devices, water splitting devices and sun screen. However, due to their large band gaps, 3.0 eV and 3.2 eV respectively, they require sensitisation to allow absorption of the visible range of the solar spectrum. The chemistry of this interface between the electron transport layer and sensitiser, and how it may be enhanced by the addition of small organic molecules is particularly important in solar cell research as it can be an area of significant efficiency losses or gains. Two surface sensitive techniques have been employed to probe the surface structure and interactions, X-ray photoelectron spectroscopy and surface Xray diffraction. In this thesis it has been shown that the band alignment of 2D SnS with anatase and rutile TiO2 is a type II overlap. Resonant photoemission spectroscopy was also employed to further understand the interactions between the TiO2 surfaces and 2D SnS, and elucidate the chemical states contributing to the valence band of SnS. XPS has also been used to understand the surface reactivity of PbS when exposed to O2 and H2O. It has been shown that upon exposure of PbS to O2 and H2O that PbSO4 and Pb hydroxyl species are produced in significant amounts. The adsorption of dopamine onto the PbS surface pre-exposure significantly reduces the degradation of the PbS surface. Surface X-ray diffraction was then used to further define the arrangement of dopamine on anatase TiO2 (101) surface, which is a system that has attracted a lot of research interest both theoretical and experimental. This study uses current theoretical and experimental models of the dopamine/anatase TiO2 structure to compare with surface X-ray diffraction data recorded, allowing the geometry of dopamine on the anatase TiO2 surface to be defined.

Diamond Keywords: Photovoltaics

Subject Areas: Materials, Chemistry

Instruments: I07-Surface & interface diffraction

Added On: 12/05/2021 15:29

Discipline Tags:

Inorganic Chemistry Physical Chemistry Materials Science Energy Materials Physics Surfaces interfaces and thin films Chemistry

Technical Tags:

Diffraction Spectroscopy Surface X-ray Diffraction X-ray Photoelectron Spectroscopy (XPS)