Georgieva, Zheni N.
(2022)
Chiral Perovskites: Generating and Investigating Chiro-optical Response in Inorganic and Hybrid Perovskite Nanomaterials.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
This is the latest version of this item.
Abstract
The field of chiral nanomaterials, having only emerged over the last two decades, has generated immense interest and research efforts from a multidisciplinary community of physicists, chemists, and biologists. Motivated by the promise of applications in sensing, metamaterials, photovoltaics, quantum computing, and others, chirality has been imparted on many classes of nanomaterials, such as metal and semiconductor quantum dots. Chiral perovskites are one of the most recently established classes of chiral semiconductor nanomaterials. This work is dedicated to the development and examination of chiral imprinting methodologies for perovskite materials with different morphologies and compositions. Firstly, chirality was imprinted onto organic-inorganic perovskite nanoplatelets via a co-capping ligand shell consisting of a chiral and achiral ligand. The study was the first account of direct synthesis of colloidal chiral perovskites. In the second study of this dissertation, the chiral nanoplatelet methodology was expanded to multiple halide and ligand compositions and the relationship between ligand shell composition and chiroptical activity was studied experimentally and computationally as a function of concentration and temperature. It was determined that electronic imprinting on perovskites is highly dependent not only on the number, but also the arrangement and orientation of chiral ligands on the nanoplatelet surface. Next, a second methodology for imparting chirality was established, this time for all-inorganic cesium lead bromide nanocrystals via a post-synthetic ligand modification. The method was shown to produce high degrees of circular dichroism with multiple chiral amine ligands. This discovery was followed by a study of the size-dependence of chirality in cesium lead bromide nanoparticles, where three different size regimes of perovskite nanoparticles were endowed with chirality via post-synthetic ligand exchange and their chiroptical properties were studied as a function of nanoparticle size, as well as ligand shell composition. CD intensity was found to depend strongly on the nanoparticle size with smaller sizes showing higher degrees of chirality. Finally, the magneto-optic properties of 2D hybrid organic-inorganic perovskites were examined and the material was found to change the magnetization of an adjacent ferromagnetic substrate when irradiated with linearly polarized light, demonstrating the existence of interfacial magnetization states via the CISS effect in this material.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
10 October 2022 |
| Date Type: |
Publication |
| Defense Date: |
12 July 2022 |
| Approval Date: |
10 October 2022 |
| Submission Date: |
6 July 2022 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
213 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Chemistry |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
chiral perovskite |
| Date Deposited: |
10 Oct 2022 19:43 |
| Last Modified: |
10 Oct 2022 19:43 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/43305 |
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