Yu, Fangda
(2016)
Internal Polarization Effect in Perovskite Solar Cells.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Rapid development of perovskite solar cells (PSCs) in recent years has attracted a lot of attention in the photovoltaic research field. Two types of TiO2 nano-scaled morphologies, nanoparticle and nanowire, play an important role in PSCs as a scaffold for the photoactive component of the PSCs. These two different morphologies also result in different electron transporting behavior in PSC. In this thesis, PSC samples are fabricated using both types of morphologies and their photovoltaic behaviors are compared with each other. Single crystalline rutile TiO2 nanowire is fabricated on fluorine doped tin oxide (FTO) substrates by a microwave assisted hydrothermal method. This method is very sensitive to many parameters, which cause TiO2 nanowire samples with multiple lengths, densities and aspect ratios to be fabricated. TiO2 nanoparticle layer is fabricated by spin coating TiO2 mesoporous paste on an FTO substrate. The TiO2 nanowire based PSC has a power convert efficiency (PCE) of 14.5% and TiO2 nanoparticle based PSC’s has a PCE of 12.9%. Photovoltaic measurements are applied to explain the carrier transport behavior. I-V measurement shows that the hysteresis effect in TiO2 nanoparticle based PSC is large. IPCE measurement shows that the illumination frequency dependence of photocurrent in TiO2 nanowire based PSC is large. As the illumination frequency increases, the photocurrent of PSCs at the short circuit condition decreases. Electron lifetime measurement presents the electron diffusivity and lifetime are longer in the nanowire based PSCs. Space charge polarization phenomenon is introduced to explain the different photovoltaic performance of the nanowire and nanoparticle based PSCs.
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| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
25 January 2016 |
| Date Type: |
Publication |
| Defense Date: |
20 November 2015 |
| Approval Date: |
25 January 2016 |
| Submission Date: |
24 November 2015 |
| Access Restriction: |
2 year -- Restrict access to University of Pittsburgh for a period of 2 years. |
| Number of Pages: |
85 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Materials Science and Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Perovskite solar cell; space charge polarization; hysteresis; TiO2 morphology |
| Date Deposited: |
25 Jan 2016 17:02 |
| Last Modified: |
25 Jan 2018 06:15 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/26467 |
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