Document Type

Dissertation - Open Access

Award Date

2016

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical Engineering and Computer Science

First Advisor

Qiquan Qiao

Keywords

charge transport, crystallization, grain boundary potential, humidity, perovskite solar cells

Abstract

The effect of temperature, humidity and water on the grain boundary potential and charge transport within the grains of pervoskite films prepared by sequential deposition technique. Grain boundary potential of perovskite films exhibited variation in electrical properties with humidity level, temperature and water concentration in methyl ammonium iodide solution. X-ray diffraction (XRD) indicates the formation of PbI2 phase in perovskite film with increasing temperature, humidity and adding larger quantity of water in methyl ammonium iodide solution. It is found that optimum amount of lead iodide helps for the passivation of perovskite film. Spatial mapping of surface potential in the perovskite film exhibits higher positive potential at grain boundaries compared to the surface of the grains. Back recombination barrier between TiO2- perovskite increases to 378 meV for perovskite film annealed at 100 ºC for 15 min. Grain boundary potential barrier were found to increase from ~35 meV to 80 meV for perovskite film exposed to 75% RH level compared to perovskite film kept inside glove box. Optimum amount of water which increases the solar cell performance by increasing the crystallinity of perovskite film was found to be 5% by volume of IPA. Results show strong correlation between temperature, humidity level, electronic grain boundary properties and device performance of perovskite solar cells.

Library of Congress Subject Headings

Solar cells -- Materials

Perovskite Nanotechnology

Nanostructured materials

Charge transfer

Description

Includes bibliographical references (pages 123-137)

Format

application/pdf

Number of Pages

153

Publisher

South Dakota State University

Rights

Copyright © 2016 Nirma Adhikari

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