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Efficient and Stable Halide Perovskite Devices

Lee, Seongha (2022) Efficient and Stable Halide Perovskite Devices. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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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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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairLee,
Committee MemberLee,
Committee MemberHornbostel,
Committee MemberXiong,
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


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