The effect of atmosphere on lead halide perovskites
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2019
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| Online Access: | https://hdl.handle.net/1721.1/121662 |
| _version_ | 1826196325391138816 |
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| author | Brenes, Roberto(Scientist in electrical engineering and computer science)Massachusetts Institute of Technology. |
| author2 | Vladimir Bulović. |
| author_facet | Vladimir Bulović. Brenes, Roberto(Scientist in electrical engineering and computer science)Massachusetts Institute of Technology. |
| author_sort | Brenes, Roberto(Scientist in electrical engineering and computer science)Massachusetts Institute of Technology. |
| collection | MIT |
| description | This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. |
| first_indexed | 2024-09-23T10:25:08Z |
| format | Thesis |
| id | mit-1721.1/121662 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T10:25:08Z |
| publishDate | 2019 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1216622023-05-30T13:26:11Z The effect of atmosphere on lead halide perovskites Brenes, Roberto(Scientist in electrical engineering and computer science)Massachusetts Institute of Technology. Vladimir Bulović. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science. Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Electrical Engineering and Computer Science. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019 Cataloged from student-submitted PDF version of thesis. Includes bibliographical references (pages 123-133). Metal halide perovskites are exciting materials for low-cost optoelectronic devices such as solar cells and LEDs. At present, perovskite materials still suffer from substantial non-radiative decay, particularly under solar illumination conditions, and are therefore yet to reach their full potential. In this thesis, we demonstrate the use of light and atmospheric treatments on polycrystalline perovskite films, resulting in minimal non-radiative losses and properties approaching those of perovskite single crystals and even the best crystalline semiconductors reported to date. We show that by combining light and atmospheric treatments, we can increase the internal luminescence quantum efficiencies of polycrystalline perovskite films from 1% to 89%, with carrier lifetimes of 32 [mu]s and diffusion lengths of 77 [mu]m, comparable with perovskite single crystals. Remarkably, the surface recombination velocity of holes in the treated films is 0.4 cm/s, approaching the values for passivated crystalline silicon, which has the lowest values for any semiconductor to date. The enhancements translate to solar cell power-conversion efficiencies of 19.2%, with a near-instant rise to stabilized power output, consistent with suppression of ion migration. Also, we use in-situ microphotoluminescence measurements to elucidate the impact of light-soaking individual methylammonium lead iodide grains while immersing them with different atmospheric environments. We show that emission from each grain depends sensitively on both the environment and the nature of the specific grain, i.e., whether it shows good (bright grain) or poor (dark grain) luminescence properties. We find that the dark grains show substantial rises in emission, while bright grain emission is steady when illuminated in the presence of oxygen and/or water molecules. We find that oxygen molecules bind particularly strongly to surface iodide vacancies which, in the presence of photoexcited electrons, lead to efficient passivation of the carrier trap states that arise from these vacancies. This thesis reveals a unique insight into the nature of nonradiative decay and the impact of atmospheric passivation on the macro- and micro-scale properties of perovskite films. by Roberto Brenes. M. Eng. M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science 2019-07-15T20:31:55Z 2019-07-15T20:31:55Z 2019 2019 Thesis https://hdl.handle.net/1721.1/121662 1102055527 eng MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 133 pages application/pdf Massachusetts Institute of Technology |
| spellingShingle | Electrical Engineering and Computer Science. Brenes, Roberto(Scientist in electrical engineering and computer science)Massachusetts Institute of Technology. The effect of atmosphere on lead halide perovskites |
| title | The effect of atmosphere on lead halide perovskites |
| title_full | The effect of atmosphere on lead halide perovskites |
| title_fullStr | The effect of atmosphere on lead halide perovskites |
| title_full_unstemmed | The effect of atmosphere on lead halide perovskites |
| title_short | The effect of atmosphere on lead halide perovskites |
| title_sort | effect of atmosphere on lead halide perovskites |
| topic | Electrical Engineering and Computer Science. |
| url | https://hdl.handle.net/1721.1/121662 |
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