Date of Award

2019-01-01

Degree Name

Doctor of Philosophy

Department

Computational Science

Advisor(s)

Rajendra R. Zope

Second Advisor

Tunna Baruah

Abstract

Methyl ammonium lead halide (MAPbX3) perovskite based solar cells have recently emerged as promising class of materials for photovoltaic applications with efficiencies reaching over 22%. Designing interfaces with strong binding is vital to developing efficient, high-performing solar cells. Fullerene-based materials are widely employed as efficient electron acceptors and can serve as electron transporting layer in perovskite based solar cells. We have studied interfaces of methyl ammonium lead iodide MAPbI3 with Sc3N@C80 fullerene and Sc3N@C80PCBM fullerene derivate within the density functional formalism. Different surface terminations and orientations of the methyl ammonium are examined for binding of the fullerene layer. Our calculated binding energies shows the possibility of adsorption of the fullerene and its derivative on the perovskite surface. The changes in the electronic structure of the perovskite surface due to the fullerene layer is studied.

We have also studied the structural, electronic, and magnetic behavior of Mn based olivines A2BX4 (A=Mn, B=Si, X=S, Se). The olivine chalcogenides are antiferromagnets and show linear trend in the transitional temperature with decrease of transition temperature from 86K for Mn2SiS4 to 66K for Mn2SiSe4. We studied Mn2SiS4-xSex for x = 0 to x = 4 through first principles calculations for the structural, electronic, and antiferromagnetic spin arrangements of the four different compositions of Mn2SiS4-xSex. Our spin magnetic moments, density of states, and bandgap are comparable to the available experimental data. We also find several spin structures can exist depending on the doping content.

Language

en

Provenance

Received from ProQuest

File Size

144 pages

File Format

application/pdf

Rights Holder

Bethuel Omutiti Khamala

Download

Share

COinS