Lee, Seongha
(2022)
Efficient and Stable Halide Perovskite Devices.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Photovoltaics (PVs), which convert absorbed solar energy into electricity, is one of the promising energy devices. They can reduce carbon footprint, providing sustainable energy resources to society. Recently, organo-lead-halide perovskite, APbX3 (A= CH3NH3+, CH2(NH2)2+, X=I-, Cl-, Br-) has attracted a huge amount of interest due to its excellent light absorption and carrier transport behavior. These unique properties provide new promises for the perovskite solar cells (PSCs) and resistive random-access memory (ReRAM) which is a key device in the area of renewable energy and neuromorphic computing, respectively. However, this material has a few obstacles such as large I-V hysteresis, interface carrier trapping, and long-term instabilities over humidity and UV light. This study addresses these fundamental problems through comprehensive research on the inorganic carrier transport layer and the passivation coating.
First, NiO is chosen as a hole transport layer to reduce a hysteresis problem of PSCs. Experimental and simulation results show that the reduction in the residual stress improves the electrical quality of the oxidized Ni film and improves the hole transport.
Second, the effect of the CH3NH3PbI3-TiO2 interface on the carrier transport and bipolar switching is studied. While the realignment of defects in the perovskite layer results in an undesired hysteresis issue in PSCs, this behavior can help to design the ReRAM device. The interface controls the conductive chain formation and causes the asymmetric bipolar resistive switching.
Third, polymer-oxide nanoparticle composites are studied to elongate the lifetime of the perovskite layer. Interpenetrating polymer networks (IPNs) exhibit better passivation behavior than individual polymer. In addition, the addition of oxide nanoparticles to the IPNs changes the surface wettability and makes a twisted path for permeating water molecules. As a result, the encapsulation dramatically suppresses the degradation process in a standardized damp heat aging condition (85/85 ℃/RH condition).
Last, the phosphors embedded anti-reflective coating (ARC) layer is explored to improve the stability of PSCs under UV light. This new ARC layer converts UV light to visible light, resulting in the better UV resistance and higher photocurrent generation rate of the PSCs.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
16 January 2022 |
| Date Type: |
Publication |
| Defense Date: |
28 October 2021 |
| Approval Date: |
16 January 2022 |
| Submission Date: |
2 November 2021 |
| Access Restriction: |
1 year -- Restrict access to University of Pittsburgh for a period of 1 year. |
| Number of Pages: |
138 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Perovskite solar cell, Resistive switching, Stability |
| Date Deposited: |
16 Jan 2022 18:19 |
| Last Modified: |
16 Jan 2023 06:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/41902 |
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